Death-Watch 

and Spider Beetles 

of Wisconsin

Coleoptera: Ptinidae

Rachel A. Arango

Daniel K. Young

United States

Department of

Agriculture

Forest Service

Forest

Products

Laboratory

General

Technical

Report

FPL–GTR–209
June 2012

Arango, Rachel A.; Young, Daniel K. 2012. Death-watch and spider beetles 

of Wisconsin—Coleoptera: Ptinidae. General Technical Report 

FPL-GTR-209. Madison, WI: U.S. Department of Agriculture, Forest 

Service, Forest Products Laboratory. 158 p.

A limited number of free copies of this publication are available to the 

public from the Forest Products Laboratory, One Gifford Pinchot Drive, 

Madison, WI 53726–2398. This publication is also available online at 

www.fpl.fs.fed.us. Laboratory publications are sent to hundreds of libraries 

in the United States and elsewhere.

The Forest Products Laboratory is maintained in cooperation with the 

University of Wisconsin. 

The use of trade or firm names in this publication is for reader information 

and does not imply endorsement by the United States Department of 

Agriculture (USDA) of any product or service.

The USDA prohibits discrimination in all its programs and activities on the 

basis of race, color, national origin, age, disability, and where applicable, 

sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part 

of an individual’s income is derived from any public assistance program. 

(Not all prohibited bases apply to all programs.) Persons with disabilities 

who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET 

Center at (202) 720–2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence 

Avenue, S.W., Washington, D.C. 20250–9410, or call (800) 795–3272 

(voice) or (202) 720–6382 (TDD). USDA is an equal opportunity provider 

and employer.

Abstract

Critical insights relating to the distribution, natural history, 

and abundance of Ptinidae sensu lato, in Wisconsin and 

North America have been overlooked in many faunistic surveys and taxonomic studies, in part due to the relative difficulty in working with the contractile nature of many species 

and complexity of certain taxonomic characters. Work by 

H.C. Fall, R.E. White, and T.K. Philips significantly aided 

in the understanding of this family, although numerous 

genera are still in need of major revision. This study is the 

first state-wide survey of Wisconsin Ptinidae. It provides a 

comprehensive list of all ptinid species documented from 

Wisconsin, with taxonomic keys for their identification. 

Profiles for each species were compiled, including a taxonomic overview, capsule description, species diagnosis, and 

overview of their natural history. Specimens were collected 

using a variety of methods during two field seasons; Lindgren funnel traps and flight intercept traps were particularly 

significant. Trap samples from previous faunistic surveys of 

other taxa and mounted specimens from private and public 

research collections were also examined. Seventy-eight 

Wisconsin pest control companies and the University of 

Wisconsin insect diagnostic laboratory were consulted for 

information regarding indoor pest species of Ptinidae. During this survey, 28 genera and 64 species of Ptinidae were 

documented from the state from 2,063 specimens. Of these, 

14 genera and 46 species are considered new state records, a 

72% increase from the number of species known previously. 

Keywords: Ptininae, Eucradinae, Ernobiinae, Anobiinae, 

Ptilininae, Xyletininae, Dorcatominae, Mesocoelopodinae

Acknowledgments

This work would not have been possible without the support of countless individuals. We thank the Forest Products 

Laboratory for funding support (Arango), especially to 

Carol Clausen, Frederick Green III, and Michael Ritter. Special thanks to Dr. Ken Raffa and Dr. R. Chris Williamson for 

careful review of the project and manuscript. We acknowledge Tom Kuster for the scanning electron microscope 

images, Regis Miller and Mike Wiemann for wood identifications, Tivoli Gough for assistance in preparing figures, 

James Anderson for editing support, and Dan Lindner for 

fungal identifications. We are also indebted to colleagues 

in the “Young Lab”: Craig Brabant, Peter DeVries, John 

Dorshorst, Jeff Gruber, Kyle Johnson, Nadine Kriska, Dan 

Marschalek, Michele Price, and Andrew Williams.

Thanks to the Wisconsin Chapter of The Nature Conservancy and Wisconsin Department of Natural Resources for 

authorizing collecting permits and support for survey projects, as well as to the numerous pest control companies that 

were instrumental in obtaining information regarding stored 

product pests (especially Dan Keohane, Randy Kalk, and 

Mark Johll from Alternative Pest Solutions and Ted Snyder, 

from Batzner Pest Control). We gratefully acknowledge 

Phil Pellitteri whose extensive knowledge of stored product 

insects and uncanny ability to identify insect pieces sent in 

to the diagnostic lab greatly aided the project.

We thank Keith Philips for numerous taxonomic discussions 

with respect to Ptinidae and for providing initial specimen 

determinations to help us develop a reference collection. 

Tom Phillips graciously provided pheromone lures. We 

thank the curators who allowed access to collections under 

their care: Steve Krauth, University of Wisconsin Insect 

Research Collection, James Boone, Field Museum of Natural History, and Creighton Freeman, Charles A. Triplehorn 

collection at The Ohio State University. 
Contents

Abbreviations.................................................................... ii

Collection Codes............................................................... ii

Introduction....................................................................... 1

Family Ptinidae ................................................................. 2

 Distribution ................................................................... 2

 Anatomy........................................................................ 2

 Taxonomy...................................................................... 3

 Natural History.............................................................. 3

Materials and Methods...................................................... 4

 Material Examined........................................................ 4

 Field Collection Methods.............................................. 4

 Specimen Preparation and Curation.............................. 5

 Methods for Diagnoses................................................. 5

 Images and Illustrations................................................ 5

Family Ptinidae Latreille, 1802......................................... 6

Key to the Wisconsin Subfamilies of Adult 

Ptinidae ............................................................................. 6

Subfamily Ptininae............................................................ 6

 Key to the Wisconsin Genera of Adult Ptininae ........... 8

 Genus Gibbium Scopoli................................................ 8

 Gibbium aequinoctiale Boieldieu ............................. 8

 Genus Mezium Curtis.................................................... 9

 Mezium affine Boieldieu ........................................... 9

 Genus Pseudeurostus Heyden..................................... 10

 Pseudeurostus hilleri (Reitter)................................ 10

 Genus Ptinus Linnaeus ............................................... 11

 Key to the Wisconsin Species of Adult Ptinus........ 12

 Ptinus bimaculatus Melsheimer.............................. 12

 Ptinus clavipes Panzer ............................................ 12

 Ptinus concurrens Fall ............................................ 14

 Ptinus fur (Linnaeus) .............................................. 14

 Ptinus villiger (Reitter) ........................................... 16

Subfamily Eucradinae..................................................... 17

 Genus Eucrada LeConte............................................. 17

 Eucrada humeralis (Melsheimer)........................... 17

Subfamily Ernobiinae ..................................................... 18

 Key to the Wisconsin Genera of Adult Ernobiinae..... 19

 Genus Ernobius Thomson........................................... 19

 Key to the Wisconsin Species of Adult Ernobius... 20

 Ernobius filicornis LeConte.................................... 20

 Ernobius granulatus LeConte................................. 21

 Ernobius youngi Arango ......................................... 22

Subfamily Anobiinae ...................................................... 22

 Key to the Wisconsin Genera of Adult Anobiinae ...... 23

 Genus Hemicoelus LeConte........................................ 23

 Key to the Wisconsin Species of Adult 

 Hemicoelus.............................................................. 24

 Hemicoelus carinatus (Say).................................... 25

 Hemicoelus defectus (Fall)...................................... 26

 Hemicoelus pusillus (Fall) ...................................... 27

 Hemicoelus umbrosus (Fall) ................................... 27

 Genus Microbregma Seidlitz ...................................... 28

 Microbregma emarginatum emarginatum

 (Duftschmid)........................................................... 28

 Genus HadrobregmusThomson .................................. 29

 Hadrobregmus notatus (Say).................................. 29

 Genus Priobium Motschulsky..................................... 30

 Priobium sericeum (Say) ........................................ 31

 Genus Trichodesma LeConte...................................... 32

 Trichodesma gibbosa (Say)..................................... 32

 Genus Oligomerus Redtenbacher ............................... 33

 Key to the Wisconsin Species of Adult 

 Oligomerus.............................................................. 34

 Oligomerus alternans LeConte............................... 34

 Oligomerus brevipilis (Fall).................................... 34

 Oligomerus obtusus LeConte.................................. 35

 Oligomerus sericans (Melsheimer)......................... 36

 Genus Stegobium Motschulsky................................... 37

 Stegobium paniceum (Linnaeus)............................. 37

Subfamily Ptilininae........................................................ 39

 Genus Ptilinus Mueller ............................................... 39

 Key to the Wisconsin Species of Adult Ptilinus ..... 40 

 Ptilinus lobatus Casey............................................. 40

 Ptilinus ruficornis Say............................................. 41

Subfamily Xyletininae .................................................... 43

 Key to the Wisconsin Genera of Adult 

 Xyletininae.................................................................. 44

 Genus Euvrilletta Fall................................................. 44

 Key to the Wisconsin Species of Adult 

 Euvrilletta ............................................................... 45

 Euvrilletta brevis White .......................................... 45

 Euvrilletta harrisii (Fall)......................................... 46

 Euvrilletta peltata (Harris)...................................... 46

 Genus Vrilletta LeConte.............................................. 47

 Vrilletta laurentina Fall........................................... 48

 Genus Xyletinus Latreille............................................ 48

 Key to the Wisconsin Species of Adult Xyletinus... 49

 Xyletinus confusus White........................................ 50

 Xyletinus fucatus LeConte ...................................... 50

 Genus Lasioderma Stephens....................................... 51

 Key to the Wisconsin Species of Adult 

 Lasioderma ................................................................. 52

 Lasioderma serricorne (Fabricius) ......................... 52

Subfamily Dorcatominae ................................................ 53

 Key to the Wisconsin Genera of Adult 

 Dorcatominae.............................................................. 54

 Genus Calymmaderus Solier....................................... 55

 Key to the Wisconsin Species of Adult 

 Calymmaderus ........................................................ 55

 Calymmaderus nitidus (LeConte)........................... 55

 Calymmaderus obsoletus (Fall) .............................. 56

 Genus Byrrhodes LeConte.......................................... 57

 Key to the Wisconsin Species of Adult 

 Byrrhodes................................................................ 57

 Byrrhodes incomptus (LeConte)............................. 57

 Byrrhodes intermedius (LeConte)........................... 58

 Byrrhodes tristriatus (LeConte).............................. 59

 Genus Caenocara Thomson........................................ 60
 Key to the Wisconsin Species of Adult 

 Caenocara............................................................... 61

 Caenocara bicolor (Germar) .................................. 61

 Caenocara blanchardi Fall ..................................... 62

 Caenocara inepta Fall............................................. 63

 Caenocara oculata (Say)........................................ 64

 Caenocara tenuipalpa Fall ..................................... 64

 Genus Dorcatoma Herbst............................................ 65

 Key to the Wisconsin Species of Adult 

 Dorcatoma .............................................................. 66

 Dorcatoma falli White ............................................ 66

 Dorcatoma pallicornis LeConte ............................. 67

 Dorcatoma setulosa LeConte.................................. 68

 Genus Petalium LeConte ............................................ 68 

 Key to the Wisconsin Species of Adult Petalium ... 69

 Petalium alternatum Ford....................................... 70

 Petalium bistriatum (Say)....................................... 70

 Petalium debile Fall ................................................ 71

 Petalium incisum Ford ............................................ 71

 Petalium seriatum Fall............................................ 72

 Petalium whitei Ford............................................... 73

 Genus Protheca LeConte ............................................ 74

 Protheca hispida LeConte ...................................... 74

 Genus Sculptotheca Schilsky...................................... 74

 Sculptotheca puberula (LeConte)........................... 74

 Genus Stagetus Wollaston........................................... 75

 Stagetus profundus (LeConte) ................................ 76

 Genus Striatheca White .............................................. 76

 Striatheca lineata White ......................................... 77

Subfamily Mesocoelopodinae......................................... 77

 Genus Tricorynus Waterhouse .................................... 78

 Key to the Wisconsin Species of Tricorynus .......... 79

 Tricorynus borealis (LeConte)................................ 79

 Tricorynus castaneus (Hamilton)............................ 80

 Tricorynus confusus (Fall) ...................................... 81

 Tricorynus dichrous (Fall) ...................................... 81

 Tricorynus nigritulus (LeConte)............................. 82

 Tricorynus punctatus (LeConte) ............................. 82

 Tricorynus similis (LeConte) .................................. 83

Literature Cited ............................................................... 84

Appendix A—Checklist of Wisconsin Ptinidae.............. 91

Appendix B—Wisconsin Distribution Maps.................. 92

Figures..........................................................................108

Abbreviations

Co. County

GPS Global Positioning System

Hg Mercury

SEM Scanning Electron Microscope

SNA State Natural Area

SWA State Wildlife Area

s.l. sensu lato

TNC The Nature Conservancy

WDNR Wisconsin Department of Natural Resources

WI Wisconsin

Collection Codes

JJDC John J. Dorshorst Collection

RAAC Rachel A. Arango Collection

IRCW University of Wisconsin–Madison Insect Research 

 Collection

MPMC Milwaukee Public Museum Collection

FMNH Chicago Field Museum of Natural History 

 Collection

UWSP University of Wisconsin–Stevens Point Collection

UWOC University of Wisconsin–Oshkosh Collection

UWEC University of Wisconsin–Eau Claire Collection

OSUC Ohio State University Collection
Death-Watch and Spider Beetles 

of Wisconsin—Coleoptera: Ptinidae

Rachel A. Arango, Entomologist

Forest Products Laboratory, Madison, Wisconsin

Daniel K. Young, Professor of Entomology

University of Wisconsin, Department of Entomology, Madison, Wisconsin

Introduction

Members of Ptinidae are known commonly as “death 

watch” or “spider beetles,” the former common name referring to the mating behavior of one particular species, Xestobium rufovillosum (De Geer). Adult beetles produce a tapping or clicking noise by hitting their frons on the substrate 

within their wooden galleries (Birch and Keenlyside 1991), 

causing a sound similar to the ticking of a clock, which was 

interpreted as an omen that a loved one would soon pass on 

(Belmain et al. 2000). This tapping behavior, now known to 

be a form of communication used in finding mates (Birch 

and Keenlyside 1991, Goulson et al. 1994), evoked fear of 

impending death especially during times of plague and sickness. In fact, classic horror fiction writer Edgar Allan Poe 

alluded to these beetles in his 1843 short story, “The TellTale Heart,” in which, a murderer recounts the killing of 

an old man:

I had my head in, and was about to open 

the lantern, when my thumb slipped upon 

the tin fastening, and the old man sprang 

up in bed, crying out—“Who’s there?” 

I kept quite still and said nothing. For a 

whole hour I did not move a muscle, and 

in the meantime I did not hear him lie 

down. He was still sitting up in the bed 

listening; —just as I have done, night after 

night, hearkening to the death watches in 

the wall.

After the murder, the body is dismembered and the old 

man’s body parts are hidden beneath the wooden floorboards 

of his quarters. The killer, confident that he has foiled the 

authorities, then begins to hear the man’s heart beating from 

beneath the floor, causing him/her to confess to the crime. 

The sound of the man’s heart beat is likely in reference to 

the aforementioned “death watches.” 

At least two species of Ptinidae produce the tapping noise 

described above, even though numerous species are associated with wood products. More frequently these beetles are 

referred to as “powderpost beetles” because of their wood 

boring behavior, which causes numerous small holes in the 

infested wood upon emergence (Figs. 8 and 9). It is important to note that two families of beetles are referred to as 

powderpost beetles, with the Bostrichidae considered "true 

powderpost" beetles. Members of this family have substantially different nutritional food requirements than members 

of Ptinidae.

As it was in the mid-1800s, some ptinid species continue to 

be feared today, not as harbingers of death, but as a result of 

the economic cost associated with damage caused by their 

close association with stored food products and wooden 

materials. The economic significance of numerous ptinid 

species has been recognized for years by many sectors of 

the wood preservation industry, as well as by homeowners 

and pest control operators. Building project planners and 

developers discussing the preservation and renovation of 

historically significant structures, such as homes and wooden bridges, often cite problems with ptinids during their

renovations. Homeowners may also encounter these beetles 

in common outdoor wooden structures, such as fence posts 

and wood decking, and indoors, most commonly within 

crawl spaces or emerging from antique furniture. Some of 

the most frequently infested buildings (especially in the 

Midwest) are older barns, where moisture levels tend to be 

higher and unfinished wood relatively abundant. 

Although many ptinid species have some degree of economic significance, three are clearly the most well-known, 

cosmopolitan species. These include Stegobium paniceum

Linnaeus, the “drugstore beetle,” which obtained its name 

from its ability to develop in pharmaceutical drugs among 

many other larval food materials; Lasioderma serricorne

(Fabricius), the “cigarette beetle,” a well-known pest of 

tobacco and other stored products; and Anobium punctatum (DeGeer), the “furniture beetle,” a species that is often 

found emerging from in-home wood furnishings. These 

species have received a great deal of attention because they 

are nearly worldwide in distribution as a result of increased 

global commerce. Unfortunately, much of the past research 

focused exclusively on characteristics of these and other 

economically important species, with little attention given 

to the remainder of the family in terms of distribution and 

abundance. Significant differences undoubtedly exist between the species seen indoors and those that are most abundant in forested environments, but these differences are not 

well understood.
General Technical Report FPL–GTR–209

2

The aim of this study is to provide a means for recognizing all Wisconsin ptinid species regardless of economic 

significance and to offer needed figures and illustrations to 

aid in determinations, as these are typically lacking in previous publications. A comprehensive study of the diversity of 

this family will not only promote a better understanding of 

Wisconsin’s natural areas as they affect the distribution and 

range of many of these species, but also provide insight into 

the abundance of economically significant species in the 

state and their potential to become problematic in the future 

as a result of climate change and/or other environmental 

factors.

Family Ptinidae

Distribution

Ptinidae is a widely distributed group with approximately 

220 genera and more than 2,200 species known worldwide, 

with some 464 species occurring in Mexico, the United 

States, and Canada (Phillips 2002). The spider beetles 

(Ptininae) make up nearly 70 of the 220 genera known 

worldwide, with 69 of the 464 species occurring in Mexico, 

the United States, and Canada (Phillips 2002). White (1974) 

listed type species and general worldwide distributions of 

all ptinid genera, with the exception of Ptininae. Of the 

10 Ptinidae subfamilies currently recognized in North America (Lawrence and Newton 1995), eight have been found to 

occur in Wisconsin. During this survey, 28 genera and 64 

species were found from Wisconsin, a significant increase 

from the 16 genera and 18 species previously noted in literature to occur in the state. 

Anatomy

Identification of many ptinids is difficult not only due to 

their small size and compact body structure, but also because of the obscure nature of certain diagnostic characters 

(White 1971a). Understanding the evolution of body form 

in this family will undoubtedly aid in comprehension of 

many of these potentially diagnostic and phylogenetically 

important characters. White (1971a) explained in detail the 

transition from the more elongate and less contracted members of Ptininae and Eucradinae to the highly compacted 

body forms of Dorcatominae and Mesocoelopodinae. The 

ability to recognize the various morphological adaptations, 

which allow many of these species to contract their appendages into cuticular grooves, is essential for taxonomic work 

in this family.

For Wisconsin fauna, the overall body form, antennae, 

shape of the prothorax, proximity of the mandibles to the 

metathoracic ventrite when the body is contracted, shape of 

the anterior margin of the metathoracic ventrite, and shape 

of the metathoracic coxae are the most useful characters 

in subfamilial classification. Ptininae, hypothesized to be 

the most primitive of all ptinid subfamilies (Philips 2000), 

exhibits a range of body forms in the Wisconsin fauna, but 

it is easily recognized by the long, filiform antennae with 

the antennal insertions close together between the eyes and 

separated by a narrow, longitudinal ridge (Fig. 84), as well 

as the shape of the pronotum and lack of prothoracic lateral 

margins (Figs. 99–118). 

The closely related Eucradinae also lacks lateral prothoracic 

margins (Figs. 119–122) and has the metathoracic coxae not 

grooved to receive the metathoracic femora. Eucradines may 

be distinguished from Ptininae by the antennal insertions, 

which are further apart when viewed from the front, near the 

compound eyes. In Ernobiinae, prothoracic lateral margins 

are apparent (Figs. 124, 126, 128) and the prothoracic 

ventrite appears slightly inflated, causing the ventral 

surface to be convex to flat near the base of the head 

(Fig. 87). Members of Anobiinae, although not highly 

contractile, begin to show adaptations for reception of appendages into the ventral surface. The prothoracic ventrite 

is excavate ventrally, appearing concave and enclosing 

much of the head (Fig. 86). The prothoracic coxae are often 

separated by a prosternal process, allowing the antennae 

to lie between them when the body is contracted (Fig. 86). 

Another adaptation is the structure of the metathoracic ventrite, which may be deeply excavate anteriorly to receive the 

antennal club and prothoracic tarsi. Ptilininae is not significantly different from Anobiinae in body sculpture, except 

for the cylindrical body shape (Figs. 155–160), asperities on 

the pronotum (Figs. 92, 159, 160), and sexually dimorphic 

antennae (Figs. 36, 37, 156–160). 

Xyletininae, Dorcatominae, and Mesocoelopodinae begin 

to show a distinct reduction of the pro- and mesosternum, 

which allows for greater contraction of the head so that the 

mandibles reach, or nearly reach, the metathoracic ventrite 

when the body is retracted (Figs.172, 174, 184, 188, 190, 

196, 224, 228). Xyletininae may be distinguished from Dorcatominae and Mesocoelopodinae by the structure of the 

first abdominal ventrite, which is not grooved to receive the 

metathoracic legs (Fig. 164). Members of Dorcatominae are 

highly contractile, sometimes appearing seed-like, with the 

mandibles easily attaining the metathoracic ventrite during 

body retraction, and all appendages largely contained within 

excavations of the ventral surface (Fig. 188), including the 

first abdominal ventrite, which is grooved for reception of 

the metathoracic legs (Figs. 208, 218, 220). Mesocoelopodinae is similarly contractile except that the anterior margin of 

the metathoracic ventrite is not at all grooved for the mesothoracic tarsi but has the mesothoracic tarsi lying just above 

the metasternal process (Fig. 83).

Numerous ptinids are sexually dimorphic, especially in 

antennal formation (Figs. 21, 22, 24, 25), but also in body 

shape and size (Figs. 11–118), distance between and size of 

the compound eyes, vestiture, and shape of the last abdominal ventrite. In Ptininae, usually females but also males of 

some species are flightless, having the elytra fused. 
Death-Watch and Spider Beetles of Wisconsin

3

Taxonomy

Supraspecific taxonomy of Ptinidae has undergone numerous nomenclatural shifts over the course of its history. 

Potentially the most significant has been the inclusion of 

Ptininae (“spider beetles”) within the then Anobiidae by 

such authors as Melsheimer (1845), LeConte (1861, 1865), 

and Fall (1905). LeConte (1865) was first to organize genera 

based on the manner in which the body is contracted. Fall 

(1905) supported LeConte’s classification, “the arrangement 

of genera proposed by him at that time appears to me to 

be on the whole distinctly more natural than any other that 

has been advanced either by earlier or later authors.” Fall’s 

monographic revision incorporated the two subfamilies 

under Ptinidae, and included keys and descriptions for 

225 species, of which 132 species and 15 genera were described as new. Two genera, Hedobia and Eucrada, were 

transferred from Ptininae as intermediate forms between the 

two subfamilies into their own tribe, Hedobiini at the head 

of Anobiinae. Pic’s (1912a) catalog treated the two subfamilies as distinct families, a classification continued by Crowson (1955), although their strong relationship to members 

of Bostrichidae was also noted. In 1981, however, Crowson 

reverted back to a taxonomic scheme similar to that of 

Melsheimer, LeConte, and Fall, which was repeated by 

Lawrence and Newton (1995). Although higher taxonomy 

of this family has varied significantly, the general arrangement of the genera within the family has not changed drastically since LeConte’s (1865) and Fall’s (1905) treatments 

of the group. The taxonomic classification presented by 

Lawrence and Newton (1995) has been followed throughout 

this survey, although the family name Ptinidae is chosen as 

the correct name (Lawrence and Newton 1995): “Ptinidae 

Latreille (1802: 112) has priority over Anobiidae if the two 

families are combined as done here.” Ptinidae, including 

Ptininae, will be hereafter written as Ptinidae sensu lato

(s.l.), Ptinidae, or ptinids. Ptinidae, excluding Ptininae, will 

continue to be referred to as Anobiidae auctorum, Anobiidae, or anobiid.

Recent studies of the phylogenetic relationships of the group 

have proposed Anobiinae and Ptininae as subfamilies within 

the monophyletic Bostrichidae by Philips (2000), who found 

Anobiidae to be monophyletic without inclusion of Ptininae, 

also determined to be a monophyletic grouping. Bostrichidae was determined to be paraphyletic without the inclusion 

of both taxa (Philips 2000). Ivie (1985) studied the relationships within the Bostrichiformia as part of his dissertation 

and supported placement of Ptinidae s.l. within the Bostrichidae, but his classification was not adopted by Lawrence and 

Newton (1995).

Surprisingly few taxonomists have focused on Ptinidae, 

and as a result numerous genera are in need of major revision. LeConte (1865) was first to provide a comprehensive 

overview of the organization of this family. Fall’s 1905 publication represents the last, major, comprehensive review of 

this family in North America, drastically increasing understanding of the morphological attributes and distribution of 

this group. Fall’s revision also provided a small number of 

illustrations, a feature that was nearly entirely absent in the 

majority of previous publications. White (1971a) elaborated 

on Fall’s (1905) comprehensive key to genera (although 

excluding Ptininae) and described in detail the evolution of 

the various subfamilies by means of the manner in which 

the body is contracted. The generic taxonomic key including 

Ptininae, presented by Philips (2002), represents the most 

current treatment of this family as a whole.

Other significant publications and catalogues on North 

American Ptinidae include Melsheimer’s (1845) descriptions of new Coleoptera species in the United States; a 

description of mature anobiid larvae by Böving (1954); 

Simeone’s (1960) study of Hemicoelus carinatus (Say), 

with observations on other anobiid species; a survey of Ohio 

Anobiidae (White 1962a) and subsequent (White 1982) catalog of the Anobiidae of America north of Mexico; an overview of the beetles of the Pacific Northwest (Hatch 1961); 

and a study of Anobiidae associated with northern hardwood 

forests in central New York (Acciavatti 1972). Papp (1962) 

provided keys and descriptions for members of Ptininae. 

Pellitteri and Boush (1983) noted a number of new ptinines 

from Wisconsin during a survey of stored products insects 

in Wisconsin’s feed mills. Other ptinid researchers confined 

their focus to economically important species or taxa 

(e.g., Howe 1940, 1953, Hinton 1941, Halstead 1986, 

Spilman 1991). Additional useful catalogs or checklists 

to North American fauna include work by Hopkins (1893), 

Pic (1912a), Leng (1920), Arnett (1983), McNamara (1991), 

and Downie and Arnett (1996). 

Natural History

Ptinid larvae are typically found in well-seasoned lumber 

(10+ years old) with low starch content, as well as in dry, 

dead standing trees, where they develop in the sapwood, 

and less frequently heartwood, of hardwoods and softwoods 

(Fig. 12) (Smith and Whitman 1992, Kyhl and Seybold 

2002). The adult female lays eggs on or close to the surface 

of the wood, or other food material, in open cracks or pores 

(Smith and Whitman 1992). Once the larvae have eclosed, 

they burrow further into the wood to feed and eventually pupate; adult emergence usually occurs in the spring and summer months. Although old, dead trees and lumber are the 

most common preferred substrate for the group, larvae have 

also been shown to utilize bark, twigs, seeds, woody fruits, 

galls, fungi, and infrequently, the stems or shoots of young, 

growing trees (Phillips 2002). A wide variety of stored food 

products are also commonly infested, mostly by members of 

Ptininae, although this subfamily does include some woodboring species (Philips 2002). 

The development period for the life cycle of Ptinidae depends strongly on environmental conditions. According 
General Technical Report FPL–GTR–209

4

to some sources, development may take up to 10 years or 

more if environmental conditions are unfavorable (i.e., low 

humidity and poor nutritional content of the wood) (Fisher 

1940, Belmain et al. 2000). Some studies have indicated 

ptinid development occurs more rapidly outdoors, egg to 

pupa taking only 2–3 weeks, with complete development in 

1 year, whereas indoors, development is thought to be slower, taking 2–3 years to complete larval and pupal development (Ebeling 1978). However, there are exceptions to this 

trend. The indoor pest species L. serricorne has been found 

to have a life cycle ranging from 42 to 70 days and has been 

reared in just 47 days (Powell 1931). 

The success of this family developing within such a wide 

range of larval food materials is at least in part due to the 

endosymbiotic yeasts stored in mycetomes located at the anterior end of the larval mid-gut (although apparently lacking 

in Ptininae) (Crowson 1981). These symbionts have been 

shown to provide essential nutrients, especially steroids 

and vitamins in the B group, allowing larvae to develop not 

only in nutrient-poor food materials, but also at times in 

otherwise toxic substances (e.g., L. serricorne in tobacco) 

(Crowson 1981, Schwemmler 1989). In addition, because 

most ptinids are wood borers, they need cellulose-degrading 

enzymes, which may also be generated by these symbionts 

(Crowson 1981). 

The ability to withstand xeric conditions is particularly well 

developed in this family. As with other members of the 

Bostrichiformia, ptinids have a modified cryptonephridic 

excretory system in which the Malpighian tubules are fused 

to the hindgut and rectum, allowing for efficient resorption 

of water (Grimaldi and Engel 2005). The evolution of flightlessness in many ptinines, causing the elytra to be fused, has 

also been shown to act as a means of preserving water in dry 

conditions. Benoit et al. (2005) compared water loss rates of 

Mezium affine Boieldieu and Gibbium aequinoctiale Boieldieu to the closely related, winged lesser grain borer, Prostephanus truncatus (Horn) (Family: Bostrichidae), showing 

five times lower water loss rates in the former two species. 

This was hypothesized to be at least in part due to the fused 

elytra and ability to enter into quiescence. 

Materials and Methods

Material Examined

Specimens for this survey were obtained using a variety 

of collection techniques during two separate field seasons 

from April/May to August/September in 2006 and 2007. 

Trapping locations were chosen largely from site descriptions obtained from The Nature Conservancy (TNC) and 

the Wisconsin Department of Natural Resources (WDNR). 

Wooded areas with a variety of hardwoods, such as oaks 

and maples, were preferentially chosen, as well as areas 

of pine further north (Figs. 1–6, 15). Within the sites, and 

where possible, traps were set in areas of standing or leaning 

dead trees. Lindgren funnel and flight intercept traps were 

the primary sampling tools used because many Ptinidae are 

strong fliers and are therefore easily obtained using passive 

trapping techniques (personal communication, Tom Phillips 

and T. Keith Philips). Traps were maintained at 30 natural 

area sites across Wisconsin, 15 in central to southern Wisconsin in 2006, 14 in central to northern Wisconsin in 2007, 

and one both years. Traps were serviced every two to three 

weeks. Numerous additional sites were visited for hand 

collecting. Sorting through bulk trap samples obtained previously during related insect surveys or from other studies 

(e.g.,such as red pine pocket mortality) yielded a significant 

amount of material from additional locations. 

Collections from various museums were examined for Wisconsin material, including University of Wisconsin–Insect 

Research Collection (IRCW), Milwaukee Public Museum 

Collection (MPMC), Chicago Field Museum of Natural 

History Collection (FMNH), University of Wisconsin–

Stevens Point Collection (UWSP), University of Wisconsin–

Oshkosh Collection (UWOC), and University of Wisconsin–

Eau Claire Collection (UWEC). The Ohio State University 

C.A. Triplehorn Insect Museum (OSUC) was also visited 

for two days. Although the visit did not provide additional 

Wisconsin specimens, it was very useful in confirming identifications of species because two prominent ptinid workers, 

R.E. White and T.K. Philips, did much of their research 

and deposited many specimens in this location. In fact, the 

OSUC houses primary types for 28 ptinid species, many of 

which were described by R.E. White. IRCW specimens and 

loan material from OSUC and FMNH were heavily utilized 

for initial species determinations. 

Given that a number Ptinidae are indoor pests of woody 

materials or stored products, 78 pest control companies from 

across the state were contacted via written letter or by phone 

not only to obtain specimens but also to determine which 

species they most frequently encountered as pests within 

structures. Similarly, specimens sent to the Insect Research 

Diagnostic laboratory at the University of Wisconsin–Madison also provided evidence for which species are most prevalent as pests of stored products or building materials.

Field Collection Methods

Lindgren funnel traps consisted of a series of (8, 12, or 16) 

black funnels suspended from the branch of a tree, and terminating in a small collection cup filled half way with 

a 50% propylene glycol/50% distilled water solution 

(Fig. 13). Baits are frequently used with these types of traps, 

but because no baits have been reported to be significant 

related to ptinid sampling, baiting was experimented with 

only to a minor degree in this study. One Lindgren trap was 

baited with 95% alcohol by filling a small 60-mL, narrowmouth Nalgene bottle and inserting a cotton wick into the 

bottle so that the top was completely sealed by the cotton, 

reducing evaporation of the alcohol. The bottle was then 
Death-Watch and Spider Beetles of Wisconsin

5

tied to the side of the Lindgren trap with a small string. The 

synthetic pheromone, serricornin was also used in conjunction with a number of Lindgren funnel traps (formulated 

as developed by Dr. Tom Phillips using 5 mg of powder 

serricornin diluted in 50% hexane). Ten microliters of the 

solution was applied to small rubber stoppers, which have 

been shown to provide a slow release of the pheromone over 

a 1–2 week time span. These rubber stoppers were attached 

inside the center funnel using metal wire. 

Examination of bulk samples from previous Wisconsin 

beetle diversity studies provided some specimens from cantharidin-baited traps, or traps baited with either cantharidin, 

ipsdienol, or a combination, but no evidence suggests these 

chemicals are significant to attracting ptinids.

Flight intercept traps consisted of either a flat plastic garbage bag or a sheet of plexiglass (66 by 40.6 cm) secured 

between two trees so that the base of the bag ran along the 

midline of a colleting tray (Fig. 14). The 74.9- by 19.1-cm 

collecting tray with a filtered drain near the top was filled 

one quarter full with a 50% propylene glycol/50% distilled 

water solution.

Other collection techniques included Berlese funnel extraction, beating branches, use of a small, hanging flight intercept/ pane trap, rearing larvae, collecting at night using an 

ultraviolet (UV) or mercury vapor (Hg) lamp, and hand collecting specimens usually from dead trees or other woody 

materials. Infested wooden material and hard, woody fungi 

were placed in rearing chambers (Fig. 11) consisting of a 

20-L bucket with a clear glass bottle attached to two sides to 

collect phototropic adults. A number of ptinines were handcollected during site visits to various factories, food warehouses, and barns. 

Specimen Preparation and Curation

Field trap samples were processed as soon as possible by 

separating all ptinid specimens into 70% alcohol until they 

could be point mounted. Once mounted, specimens were labeled using 100% cotton paper with locality data including 

county, specific site, and global positioning system (GPS) 

coordinates, where possible. The collection date, collector, 

and method of collection were also included on specimen 

labels. A number of specimens required re-hydration to expose certain morphological characters, which was done by 

immersing the specimen in near-boiling (88 °C) water for 

3–5 min and using a minuten pin to extract the necessary 

structures. Characters needed for identification are noted in 

each individual subfamilial description. 

For certain genera, male genitalia had to be extracted and 

examined to confirm species identifications. Due to the 

small size and compact nature of many Ptinidae, the entire 

abdomen was generally removed after the specimen was 

re-hydrated. The abdomen was then placed in a small beaker 

with approximately 30 mL of near-boiling (88 °C) water 

and three pellets of either potassium hydroxide or sodium 

hydroxide and left covered for 20–30 min. Genitalia were 

then carefully extracted with a minuten and stored in a glass 

genitalia vial with 300 μL of glycerin, capped by a small 

rubber stopper, and pinned beneath the specimen identification label. The disarticulated abdomen was attached to a 

glue board and pinned directly below the specimen.

Label data for all specimens, including those from museum 

loans, were assigned a unique specimen code and entered 

into a database using BiotaTM software (Sinauer Associates, Inc., Sunderland, Massachusetts) (Colwell 1996). 

Specimens collected during this survey were deposited in 

the IRCW. Collection codes chosen for each specimen in 

BiotaTM correlate with the acronyms listed for each of the 

various insect collections.

Methods for Diagnoses

A relatively comprehensive list of synonyms is given for 

each species. The type species for each genus was generally 

that reported by White (1974 or 1982) for Anobiidae. Type 

species for ptinine genera were those reported in Borowski 

and Zahradník (2007). Capsule descriptions are based entirely on Wisconsin specimens and therefore may be less 

variable than if considered for the entire species range. 

Lengths and widths given represent an average of five, large 

and small specimens (where possible). Specimen length was 

measured along the meson from the anterior pronotal margin to the elytral apices. Specimen width was measured at 

the widest part of the elytra, usually along the apical quarter 

of the elytra for anobiids. Ptinines were usually measured 

near the middle of the elytral disk. All measurements were 

made using a micrometer installed in the lens of a dissecting 

microscope. Perhaps one of the most difficult characters to 

distinguish was the punctation and sculpturing of the body 

surface. The use of a small, hand-held fluorescent light 

greatly improved surface sculpture visibility, especially on 

genera such as Tricorynus. A description of the male genitalia is provided for species where necessary.

Methods of collection and larval associations are provided 

under the “Natural History” section for each species treatment. Adult phenology is given in terms of early, mid-, or 

late periods of the months collected as many were obtained 

from trap samples and therefore do not have a specific collection date. Distributions are presented as general overviews of the occurrence of each species in North America, 

north of Mexico, indicating whether the species is a new 

state record, and/or range extension from the previously 

known distribution of the species. Distribution of each 

Wisconsin species is annotated in Appendix B. 

Images and Illustrations

Line drawings were adapted from previous work (e.g., 

Fall 1905, White 1962a) or drawn from Wisconsin 
General Technical Report FPL–GTR–209

6

specimens using Adobe® Illustrator® CS3 (Adobe Systems, 

Inc., San Jose, California). Habitus images were digitally 

created using an extended depth of field microscope with 

Auto-Montage 3-D imaging software (SyncroscopyTM, 

Subfamily Ptininae

Ptininae was erected by Latreille (1802); its classification 

has varied considerably over its taxonomic history. Some 

of its species have previously been included as members of 

“Bruchidae” and Anobiidae (Papp 1962), or classified as 

Synoptics Inc., Frederick, Maryland) and edited in Adobe® 

Photoshop® CS3. All scale bars represent 1 mm where 

shown. Wisconsin county distribution maps were also 

created in Photoshop® CS3.

Family Ptinidae Latreille, 1802

Key to the Wisconsin Subfamilies of Adult Ptinidae

[Modified from White 1962a, 1971a, Philips 2002]

1 Antennal insertions close together between the eyes and separated by a ridge no wider than the 

 length of the scape (Fig. 84); abdominal ventrites 1–3 mostly fused; metathoracic coxal plates 

 absent ...........................................................................................................................................................Ptininae (p. 6)

1’ Antennal insertions far apart just in front of each eye and separated by >0.5X the total width of 

 the frons (Fig. 85); abdominal ventrites 1–2 mostly fused and metathoracic coxal plates nearly 

 always present................................................................................................................................................................... 2

2 (1’) Pronotum without lateral margins (Figs. 120, 122); metathoracic coxae not grooved for 

 reception of femora; frons without narrow ridge over bases of antennae......................................Eucradinae (p. 17)

2’ Pronotum with lateral margins (Fig. 130); metathoracic coxae grooved for reception of femora; 

 frons usually with narrow ridge over bases of antennae................................................................................................... 3

3 (2’) Outer margin of each prothoracic tibia prolonged apically into a horizontal tooth, margin 

 above finely toothed or rugose; pronotum asperate anteriorly (Figs. 92, 158–160).........................Ptilininae (p. 39)

3’ Outer margin of each prothoracic tibia not as above; pronotum never asperate anteriorly.............................................. 4

4 (3’) Head in repose very strongly deflexed and extended posteriorly; mandibles reaching or 

 nearly reaching metathoracic ventrite (Figs. 162, 188, 234) ...................................................................................... 5

4’ Head in repose deflexed but not extended posteriorly; mandibles never reaching metathoracic 

 ventrite (Figs. 124, 152).................................................................................................................................................... 7

5 (4) Metathoracic ventrite and abdomen not excavate for reception of mesothoracic and 

 metathoracic legs; head impressed or excavate beneath for reception of antennae........................Xyletininae (p. 43)

5’ Metathoracic ventrite and abdomen grooved for reception of mesothoracic and metathoracic 

 legs; head impressed beneath for reception of antenna or not impressed (Figs. 80–83) .................................................. 6

6 (5’) Metathoracic ventrite lacking tarsal grooves anteriorly (Fig. 83); hypomera never 

 visible in body retraction ...................................................................................................Mesocoelopodinae (p. 77)

6’ Metathoracic ventrite usually with tarsal grooves (note: the grooves are often most easily 

 visible on each side of the metasternal process) (Figs. 80–82); a portion of hypomera often

 visible in body retraction ................................................................................................................ Dorcatominae (p. 53)

7 (4’) Prothoracic ventrite excavated beneath, hypomera distinctly concave, more or less 

 enclosing head (Fig. 86); elytra striate (Figs. 129–154)..................................................................Anobiinae (p. 22)

7’ Prothoracic ventrite not excavated beneath, hypomera flat or convex, head free (Fig. 87); 

 elytra never striate (Figs. 123–128) ..................................................................................................... Ernobiinae (p. 18)

an independent family, Ptinidae (such as Pic 1912a, Bellés 

1994, Downie and Arnett 1996), as a subfamily within 

Anobiidae (such as Crowson 1981, Lawrence and Newton 

1995, Philips 2002, Majka 2007a), as a tribe within the 

Bostrichidae (e.g., Ivie 1985), or as the family Ptinidae s.l.
Death-Watch and Spider Beetles of Wisconsin

7

(e.g., Fall 1905, Borowski and Zahradník 2007). Authors 

who have considered Ptininae to be a valid family, without 

the inclusion of the other anobiid subfamilies, typically divided its members into the subfamilies Gibbiinae and Ptininae, the latter being something of a catch-all for species not 

included in Gibbiinae (Philips 2000). 

Recently, Philips (2000) conducted a phylogenetic analysis 

of New World Ptininae not only to determine its relationship 

to related subfamilies, but also to ascertain the placement of 

Ptinidae s.l. in higher classification, specifically as related to 

Bostrichidae. His analysis recovered Anobiidae and ptinines 

as sister taxa, suggesting both groups might be classified 

at the same hierarchical level. The Bostrichidae alone was 

found to be paraphyletic without the inclusion of Ptinidae 

s.l. Therefore, Philips (2000) suggested both Anobiidae auctorum and Ptininae might better be considered as subfamilies of Bostrichidae to maintain a monophyletic relationship, 

as had been previously suggested by Ivie (1985). Classification used in this work, however, follows that of Crowson 

(1981), Lawrence and Newton (1995), and Philips (2002), 

all of which retain Ptinidae s.l. as a valid family until further 

phylogenetic studies are completed.

Ptinines, also referred to as spider beetles, are so named 

because of their long legs, long filiform antennae, appearing 

as a fourth set of legs, and round or oval body shape causing 

the head to be hidden when viewed dorsally, giving the 

appearance of only two tagmata like spiders (Figs. 99–118). 

This subfamily, however, contains a wide variety of morphologies, including a number of myrmecophiles, such 

as Coleoaethes Philips and Gnostus Westwood, both considered to be basal within ptinine classification (Philips 

2000). Numerous species are flightless in females only or 

in both sexes, a character thought to have evolved at least 

three times within the Ptininae (Philips 2000). Body forms 

of flightless individuals tend to be short and globular (e.g., 

Gibbium Scopoli and Mezium Curtis) (Figs. 99–102) as opposed to elongate and parallel sided (e.g., males of Ptinus

Linnaeus) (Figs. 111, 112) (Philips 2000). 

Elytral fusion is hypothesized to play an important role in 

water conservation in many flightless species (Benoit et al. 

2005). Mezium affine Boieldieu and Gibbium aequinoctiale

Boieldieu are said to show significant desiccation resistance, 

with M. affine surviving nearly 3 months with no food or 

free water and laboratory cultures of G. aequinoctiale persisting 7 years without water (Ark et al. 2005, Benoit et 

al. 2005). The ability to tolerate such xeric conditions and 

survive for long periods of time without food or water sets 

spider beetles apart from many other stored products insects 

(Benoit et al. 2005).

Ptinines are mainly scavengers on dry plant or animal matter, although some are known to be ant associates and one 

species is hypothesized to be a termitophile (Zayas 1988). 

Larvae may also be found as bird or mammal nest inquilines, as well as in nests of solitary bees, where they have 

been found to feed on pollen (Linsley and MacSwain 1942). 

Within structures, they tend to breed in damp areas such as 

crevices where food product has built up (VanRyckeghem 

2004). In nature, ptinines may be found in caves, rotten 

wood, animal nests, or in damp or dry organic matter (Rees 

2004). Other known food materials include grains or grainbased products, old rodent bait, animal feces, dead insects, 

feathers, bones, animal skin, almonds, cayenne pepper, 

beans, dried fruits, raisins, fish meal, and stored hops (VanRyckeghem 2004). As a result, this subfamily contains a 

number of economically important species in North America 

as well as worldwide, such as Mezium americanum (Castelnau), M. affine, Gibbium psylloides (Czenpinski), G. aequinoctiale, Niptus hololeucus (Faldermann), Tipnus unicolor

(Piller & Mitterpacher), Trigonogenius globulus Solier, 

Ptinus clavipes Panzer, Ptinus fur (Linnaeus), Ptinus 

villiger (Reitter), Pseudeurostus hilleri (Reitter), and 

Sphaericus gibboides Boieldieu (Hinton 1941, Pellitteri 

1977, Halstead 1986, Philips 2000), of which M. affine, 

G. aequinoctiale, N. hololeucus, T. unicolor, P. hilleri, and 

S. gibboides are thought to have been incidentally introduced into the New World (Philips 2000). Many ptinines 

are also known to be resistant to cold temperatures, allowing 

them to become problematic even in colder climates 

of northern North America (VanRyckeghem 2004). 

Locating spider beetle infestations is sometimes difficult 

because many species are nocturnal (Rees 2004). Indoors, 

sticky traps may be used to monitor beetle populations 

(VanRyckeghem 2004), and traps made of cardboard or 

sacking materials in corners or crevices may also be used to 

locate spider beetles within structures (Rees 2004). Control 

efforts generally focus on removal of infested materials and 

thorough cleaning, which may involve locating and discarding old bags of feed and even rodent or other animal nests 

(VanRyckeghem 2004). Fumigation is used very rarely, and 

only in situations where the infestation is severe and cannot 

be controlled in any other manner (VanRyckeghem 2004).

Species recognition of many Ptininae has been obscured in 

the past in literature as well as in collections particularly 

with respect to species of Mezium and Gibbium, as well 

as various species of Ptinus (e.g., Ptinus latro Fabricius, 

P. villiger, P. clavipes, and P. fur). Species characterization is likely to be a problem for many species distributed 

through commerce (although also a problem with some native North American Ptinus) as isolated populations form, 

which may appear as the originating species, but begin to 

show variation as a result of genetic bottleneck, causing 

them to be considered two separate species (personal 

communication T.K. Philips). Some of these difficulties 

are discussed in the following generic diagnoses. 

Ptininae contains 11 genera and 59 species in North 

America, north of Mexico (Philips 2002). Four genera 

and eight species are known from Wisconsin. Ptinines are 

easily distinguished from all other North American Ptinidae 
General Technical Report FPL–GTR–209

8

by having the antennal insertions close together between the 

eyes, separated by a ridge less than or equal to the length of 

the antennal scape (Fig. 84) (extracted in part from Philips 

2002). Special preparation of most Ptininae is unnecessary 

Genus Gibbium Scopoli 

[Synonymy modified from Papp 1962] 

Type Species: Ptinus scotias Fabricius 1781: 74.

Gibbium Scopoli 1777: 505.

Scotias Czenpinski 1778: 51.

Worldwide, three species of Gibbium are known to be associated with stored products: G. aequinoctiale Boeildieu, 

Gibbium psylloides (Czenpinski) and Gibbium boieldieui

Levrat (Bellés and Halstead 1985). The former two species have frequently been confused in literature because the 

morphological characters separating them are obscure and 

difficult to interpret. Therefore, many publications and studies in North America regarding G. aequinoctiale are likely 

misidentified as G. psylloides. Bellés and Halstead (1985) 

clarified separation of these two species by examination of 

the male genitalia and concluded G. psylloides is largely 

Palaearctic, whereas G. aequinoctiale has the more cosmopolitan distribution, occurring mostly in warmer parts of the 

globe. Gibbium aequinoctiale is the only species likely to 

be found in North America, although G. psylloides is said to 

occur extremely rarely (Philips 2002). 

Gibbium aequinoctiale Boieldieu

(Figs. 99, 100; Map 1)

[Synonymy modified from Borowski and Zahradník 2007] 

Gibbium aequinoctiale Boieldieu 1854: 1xxxiv.

Gibbium chevrolatii Boieldieu 1854: 1xxxv.

Gibbium aegyptiacum Pic 1894: 203.

Gibbium einsteini Bellés 1980: 845.

before mounting, although in certain cases, genitalia 

may need to be extracted and examined for positive 

identification. 

Key to the Wisconsin Genera of Adult Ptininae

[Modified from Spilman 1991 and Philips 2002]

1 Elytra with appressed scales and/or rows of setae (Figs. 103–118); abdominal ventrites not 

 significantly narrower than elytra when viewed ventrally (Fig. 71)................................................................................ 2

1’ Elytra smooth and shining with none to a few scattered erect setae (Figs. 99–102); abdominal 

 ventrites 0.3–0.5X width of elytra when viewed ventrally (Fig. 72).............................................................................. 3

2 (1) Each metathoracic trochanter long, its apex reaching the elytral margin when projected 

 perpendicular to the length of the body (Fig. 70) .....................................................................Pseudeurostus (p. 10)

2’ Each metathoracic trochanter short, its apex not reaching the elytral margin (Fig. 71).............................Ptinus (p. 11)

3 (1’) Head and pronotum glabrous (Figs. 99, 100); abdomen with 4 ventrites...........................................Gibbium (p. 8)

3’ Head and pronotum densely setose (Figs. 101, 102); abdomen with 5 ventrites....................................... Mezium (p. 9)

Capsule Description (Figs. 23, 99, 100)—Length: 2.1–

2.7 mm. Width: 1.4–1.8 mm. Integument Color: dorsal 

surface orangish to dark reddish, shining; maxillary and 

labial palpi yellowish-orange; head darker orange, reddish 

or appearing blackish; anterior pronotal margin similarly 

darker, posterior area of margin lined with darkly pigmented 

circular marks. Body Form: globular, spider-like, 1.5X longer than wide. Vestiture: antennae, legs, and ventral surface 

densely clothed in coarse, golden-yellowish pubescence 

obscuring surface sculpture; pronotal and elytral disks glabrous; head with sparse yellow setae above antennal insertions, longer and denser below. Head: terminal segment of 

each maxillary palpus elongate, apically pointed; antennae 

11-segmented, nearly as long as body, filiform, separated on 

frons by a narrow, longitudinal ridge, terminal antennomere 

elongate, pointed; eyes very small, oval, flat, located just 

above antennal insertions; cranial surface striate laterally, 

smooth and sparsely punctate medially, between eyes. Pronotum: narrow; surface mostly glabrous, shining. Elytra:

fused, concealing scutellum; disk globose, widely enclosing 

body, reducing size of ventral surface; surface glabrous, 

shining. Metathoracic Ventrite: not excavate for reception 

of mesothoracic legs. Legs: not received in ventral excavations; metathoracic coxae short; metathoracic trochanters 

very long, 0.6X length of the femora. Abdomen: with 

4 ventrites (mostly obscured by pubescence); much narrower than elytra when viewed ventrally.

Diagnosis—Gibbium aequinoctiale is easily separated from 

all other North American Ptininae by the following combination of characters: antennal insertions close together 

between eyes; head, pronotum and elytra glabrous (Figs. 99, 
Death-Watch and Spider Beetles of Wisconsin

9

100); abdomen with four ventrites; abdominal ventrites only 

about a third as wide as the elytra when viewed ventrally 

(Fig. 72) (extracted in part from Philips 2002). As previously mentioned, G. aequinoctiale is commonly confused 

with G. psylloides because the character historically used for 

their separation refers to the ambiguous prominence of the 

ridges beneath the eyes. The form of the median lobe of the 

male genitalia, as described by Bellés and Halstead (1985), 

is the most accurate means in separating these two species. 

Natural History—Gibbium species are known to be detritivores, feeding on a variety of stored products (Ngamo et 

al. 2007). VanRyckeghem (2004) lists stored seeds, wheat, 

bran, stale bread, decaying animal and vegetable refuse, rat 

droppings, stored wheat, baby food, dog biscuits, cereals, 

woolens, towels, leather, paste, and tallow and opium cake 

as food material for G. psylloides from houses, hotels, warehouses, mills, granaries, bakeries, and latrines, although the 

species to which he is referring is likely G. aequinoctiale. 

All Wisconsin specimens were collected from within structures, with none found outside an urban environment. Three 

individuals were taken by a pest control company from a 

milk drying plant, where they were found crawling on the 

floor in some food debris. A few were discovered in stored 

food in the University of Wisconsin (UW) Entomology 

Department. Another large infestation was found at a pet 

food warehouse, where the beetles were developing within 

a 100+-year-old brick wall in the center of the factory. The 

company had all other walls replaced, but could not remove 

the center, load-bearing wall. Pet food debris, flour, and 

powder had built up within the cracks of the wall, which is 

where the infestation is thought to have originated. Numerous spot treatments and monitoring using sticky traps for 

several years could not resolve the problem. Heat treatments 

and/or sealing the cracks in the old center wall were recommended as other potential remediation options. 

From the latter infestation, approximately 15 live adults of 

G. aequinoctiale were collected on 26 April 2007 and maintained in a large fish tank with chicken feed (mostly grains) 

as a food source. As of January 2009, a few hundred individuals have emerged. No water source was ever provided, 

which did not appear to influence development, but did 

seem to affect behavior. Gibbium aequinoctiale adults are 

able to aestivate. This period of physical inactivity was also 

reported by Benoit et al. (2005), who suggested this behavior occurs as a result of water stress and fasting. The fused 

elytra and ability to aestivate significantly enhances survival 

in stored, old, dried materials (Benoit et al. 2005). Rees 

(2004) reported breeding conditions of G. aequinoctiale to 

be at 20–35 °C (68–95 °F) and 40–70% relative humidity, 

with the shortest development period occurring in 45 days 

at 33 °C (91.4 °F). 

Phenology—Adult specimens of G. aequinoctiale were 

recorded from within structures in Wisconsin during midNovember, late December, mid-March, and late April.

Distribution—Because G. aequinoctiale is cosmopolitan, 

it may be found in stored products across North America 

(Bellés and Halstead 1985). Pellitteri and Boush (1983) 

recorded G. psylloides from Wisconsin, although these 

specimens were actually G. aequinoctiale. In this study, 

specimens were examined from four southern Wisconsin 

counties. 

Wisconsin Records (Map 1)—The 40 specimens of G. aequinoctiale examined during this study were recorded from 

the following localities: Crawford Co. (3): Boscobel Milk 

Drying Plant; Dane Co. (3): UW Entomology Department; 

Jefferson Co. (33): Pet Food Warehouse; Milwaukee Co. 

(1): No other locality data.

Genus Mezium Curtis

[Synonymy modified from Borowski and Zahradník 2007] 

Type Species: Ptinus sulcatus Fabricius 1781: 73.

Mezium Curtis 1828: 232.

Two species of Mezium occur in North America, north of 

Mexico: M. affine and M. americanum, the former being 

more commonly encountered (Philips 2002). Both species 

are, however, considered largely cosmopolitan (Papp 1962); 

they are generally found in stored food products. Mezium

closely resembles Gibbium species, from which it is easily 

separated by the densely pubescent head and pronotum. The 

female, at least for M. affine, is similar in morphology to 

the male (Hinton 1941) and is therefore difficult to separate 

externally.

Mezium affine Boieldieu

(Figs. 101, 102; Map 2)

[Synonymy modified from Borowski and Zahradník 2007] 

Mezium affine Boieldieu 1856: 674.

Mezium hirtipenne Reiche 1864: 241.

Capsule Description (Figs. 101, 102)—Length: 2.5–

3.4 mm. Width: 1.4–1.8 mm. Integument Color: maxillary 

and labial palpi light yellowish to reddish-orange; antennae 

and appendages reddish-orange (note: only visible if setae is 

partially removed); elytra yellowish-orange to dark reddish 

or reddish-black. Body Form: globular, spider-like, 1.8X 

longer than wide. Vestiture: antennae, head, pronotum, legs, 

and ventral surface densely clothed in coarse, golden-yellowish scales and thick setae, obscuring surface sculpture; 

pronotum with two parallel tomentose rows of suberect to 

erect setae; elytra with a narrow tomentose basal collar, partially interrupted medially; long, erect setae sparsely distributed medially, posterial elytral collar; surface of metathoracic ventrite and abdomen completely concealed by yellowish 

scales and sparse erect setae. Head: terminal segment of 

each maxillary palpus elongate, apically pointed; antennae 

11-segmented, nearly as long as body, filiform, narrowly 

separated on frons; terminal antennomere distinctly pointed 

apically; eyes small, convex, round, located above and lateral of antennal insertions; surface sculpture obscured by 
General Technical Report FPL–GTR–209

10

pubescence. Pronotum: broad, nearly parallel-sided when 

viewed dorsally; disk dorsally and laterally adjacent to elytral disk; surface sculpture obscured by pubescence. Elytra:

fused, concealing scutellum; disk globose, widely enclosing 

body, reducing size of ventral surface; surface glabrous, 

shining, except pubescent basal margin of disk. Metathoracic Ventrite: not excavate for reception of mesothoracic 

legs. Legs: not received in ventral excavations; metathoracic 

trochanter 0.3X length of the metathoracic femora. Abdomen: with 5 ventrites (difficult to count because of pubescence); much narrower than elytra when viewed ventrally.

Diagnosis—Mezium affine may be distinguished from all 

other North American Ptininae by a combination of the 

following characters: antennal insertions close together 

between eyes; head and pronotum densely setose; pronotum with basal collar entire on each side, only interrupted 

medially; pronotum with tomentum parallel on disk, not 

appearing convergent apically; abdomen with 5 ventrites; 

abdominal ventrites only about a third as wide as the elytra 

when viewed ventrally (e.g., Fig. 72) (extracted in part from 

Philips 2002). The form of the basal pronotal tomentose collar and shape of the pronotal disk will readily separate this 

species from the cosmopolitan Mezium americanum (Castelnau) (Spilman 1991). 

Natural History—As with G. aequinoctiale, M. affine

(known commonly as the shiny spider beetle or Northern 

spider beetle) is also known to survive extended periods 

without water (Benoit et al. 2005) and are therefore able to 

infest a variety of dry food products. Rees (2004) reported 

breeding conditions of M. affine to be at 20–33 °C (68–

91.4 °F) and 30–70% relative humidity, with the shortest 

development period occurring in 62 days at 29–33 °C (84.2–

91.4 °F). Howe (1953) found this species to be capable of a 

tenfold increase in population in three months. In Wisconsin, specimens were collected from inside the Milwaukee 

Public Museum library, “in store room,” from “paper birch 

infested by Agrilus anxius,” from a lab culture, and from 

inside a light fixture inside a home. It is likely that all records were from indoor collections, including the specimen 

recorded from paper birch, as it was collected during winter 

on 01 January 1941. 

Phenology—Adults of M. affine were recorded from within 

Wisconsin structures nearly all months of the year.

Distribution—Mezium affine has a relatively cosmopolitan 

distribution and has been found from Europe, North Africa, 

southeastern Canada, and northeastern United States 

(Papp 1962).

In this study, specimens were examined from three Wisconsin counties; they constitute a NEW STATE RECORD. 

Wisconsin Records (Map 2)—The 32 specimens of 

M. affine examined during this study were recorded from 

the following localities: Crawford Co. (10): Prairie Du 

Chien; Dane Co. (19): Madison; Madison Lab Culture; no 

other locality data; Milwaukee Co. (3): Milwaukee Public 

Museum Building.

Genus Pseudeurostus Heyden

[Synonymy modified from Borowski and Zahradník 2007] 

Type Species: Ptinus frigidus Boieldieu 1854: 1xxxii.

Eurostus Mulsant & Rey 1868: 49 (not Dallas 1851 or 

Dumeril 1853).

Pseudeurostus Heyden 1906: 424.

Niptomimus Pic 1950: 10.

Niptinus Yang 1980: 26.

Aalbu and Andrews (1992), in agreement with Spilman 

(1975), suggested species of Pseudeurostus should be 

included under the genus Niptus because both species of 

Pseudeurostus, and all species of Niptus with the exception 

of N. hololeucus, have a strongly reduced fourth abdominal 

ventrite, which they considered a clear synapomorphy: “if 

Pseudeurostus is to be generically separated from Niptus, 

then N. hololeucus, the type species of Niptus, needs also 

to be separated from both groups, making it necessary for 

a new generic name for the eight ‘wild’ species of Niptus.” 

In a more recent phylogenetic analysis (Philips 2000), Niptus + Pseudeurostus was recovered as a polyphyletic taxon 

containing three distinct monophyletic lineages, supporting 

the use of Pseudeurostus as a valid genus and “creation of a 

new genus for North and possibly South American Niptus.” 

Two species of Pseudeurostus occur in North America, 

Pseudeurostus kelleri Brown recorded from Utah to Montana, and Pseudeurostus hilleri (Reitter), from various locations across southern Canada (Brown 1959, Papp 1962, 

Philips 2002). The holotype and eight paratypes of P. kelleri

were recorded “60 feet inside the entrance of Logan Cave” 

in Utah, while P. hilleri has been taken infrequently from 

inside warehouses (Brown 1959). To date, only P. hilleri has 

been found in Wisconsin. 

Members of Pseudeurostus may be distinguished from all 

other Wisconsin Ptinidae by the following combination of 

characters: antennal insertions close together between the 

eyes; metathoracic trochanters long, exceeding the elytral 

margin when projected perpendicular to the body (Fig. 70); 

abdominal ventrites not significantly narrower than the elytra when viewed ventrally (extracted in part from Philips 

2002).

Pseudeurostus hilleri (Reitter)

(Figs. 19, 70, 103, 104; Map 3)

[Synonymy modified from Brown 1959, Borowski and 

Zahradník 2007] 

Niptus hilleri Reitter 1877: 378.

Eurostus sahoroensis Ohta 1930: 106.

Eurostus yezoensis Ohta 1930: 107.

Eurostus hilleri (Reitter); Howe 1940: 73.
Death-Watch and Spider Beetles of Wisconsin

11

Eurostus alienus Brown 1940: 116.

Niptus subelongatus Pic 1950: 10.

Pseudeurostus hilleri (Reitter); Philips 2000.

Capsule Description (Figs. 19, 70, 103, 104)—Length: 

2.5–2.7 mm. Width: 1.3–1.6 mm. Integument Color:

uniformly dark reddish-brown; maxillary and labial palpi 

yellowish-brown. Body Form: oval, 1.8X longer than wide.

Vestiture: pubescence yellowish; head with fine, moderately dense, recumbent setae; pronotum with mostly bristling, 

suberect to decumbent, moderately sparse setae; elytral intervals with long, erect to recumbent setae; elytral strial setae reclinate to recumbent; ventral surface with vestiture of 

fine, moderately dense, recumbent setae. Head: eyes small, 

almond-shaped, widely separated on front; antennal insertions close together between eyes, separated by a narrow, 

longitudinal carina; antennae 11-segmented, filiform; frons 

medially with a short, longitudinal sulcus; surface densely 

granulate, punctate. Pronotum: widest diameter of pronotum 1.8X shorter than widest diameter of elytra; disk similar 

in shape to the elytra, constricted basally; lateral margins 

absent; surface densely granulate with large, shallow punctures. Elytra: fused, discal striae not to weakly impressed, 

surface shining, punctate, strial punctures deep, regularly 

spaced, separated by about 2X the diameter of a puncture; 

membranous metathoracic wings absent. Metathoracic 

Ventrite: narrow, not excavate for reception of mesothoracic legs; surface with large, crater-like punctures laterally 

and along entire anterior margin, granulate laterally, 

smooth and shining medially, between metathoracic coxae. 

Legs: not received in ventral excavations; prothoracic coxae 

narrowly separated by a prosternal process; mesothoracic 

coxae widely separated by a broad, quadrate mesosternal 

process; metathoracic coxae separated by 5X the separation 

of the mesothoracic coxae; metathoracic trochanters long, 

exceeding the elytral margin when projected perpendicular 

to the body. Abdomen: with 5 ventrites; 4th ventrite narrow, 

about 0.4X the width of 3rd ventrite; surface of ventrites 

1–3 with large, crater-like punctures and smaller punctures; 

surface of ventrites 4–5 with smaller punctures only; abdomen with brush of long, erect setae arising from two, closely 

adjacent, large, shallow punctures on the apical region of the 

5th ventrite (♀♀) or long, erect setae absent (♂♂).

Diagnosis—Pseudeurostus hilleri may be readily distinguished from the similar Ptinus species by having metathoracic trochanters long and exceeding the elytral margin 

when projected perpendicular to the body (Fig. 70). Males 

and females are easily separated by the long, erect setae on 

the fifth abdominal ventrite (Hinton 1941). 

Natural History—Pseudeurostus hilleri is thought to have 

been introduced to both Canada and England (Papp 1962). 

Hinton (1941) reported this species from within warehouses 

and granaries, where it can become a pest of stored products, such as large quantities of cereals (Hatch 1961). This 

species has been reared on whole wheat flour and brewer’s 

yeast and is said to feed on rat and mouse feces in England 

(Hatch 1961). Rees (2004) reported breeding conditions of 

P. hilleri to be at temperatures below 28 °C (82.4 °F) and 

40–70% relative humidity, with the shortest development 

period from egg to adult to be 53 days at 20 °C (68 °F). The 

two Wisconsin specimens were collected from an animal 

food processing plant in a food trap set during a 1976 survey 

of stored products pests in southern Wisconsin feed mills 

(personal communication, Phil Pellitteri).

Phenology—Adults of P. hilleri were recorded in Wisconsin 

on August 9 and 17 of 1976.

Distribution—Pseudeurostus hilleri, described from Japan 

by Reitter (1877), was first recorded in North America from 

New England by Johnson (1921) (Papp 1962) and from inside warehouses in Canada in 1936 (Brown 1959). Within 

Canada, it is known from Quebec, New Brunswick, Ontario, Alberta, and British Columbia (Brown 1959, Philips 

2002). This species is also said to be widely distributed in 

Scotland, where it is considered a pest of stored products, as 

well as from Great Britain (Hinton 1941). Pellitteri (1977) 

and Pellitteri and Boush (1983) encountered this species in 

Wisconsin during a survey of stored product insects found 

in southern Wisconsin feed mills, which provided the only 

specimens examined from the state.

Wisconsin Records (Map 3)—The two specimens of 

P. hilleri examined during this study were recorded from the 

following locality: Dane Co. (2): Madison.

Genus Ptinus Linnaeus

Type Species: Cerambyx fur

Linnaeus 1758: 393. 

Ptinus Linnaeus 1767: 537. 

Six subgenera are considered valid in Ptinus worldwide: 

Bruchoptinus Reitter, Cyphoderes Mulsant & Rey, Gynopterus Mulsant & Rey, Pseudoptinus Reitter, Ptinus

Linnaeus, Tectoptinus Iablokoff-Khnzorian & Karapetyan 

(personal communication, T.K. Philips). Thirty-eight species of Ptinus are known to occur in North America, north 

of Mexico, as listed by Papp (1962), although the status 

of two nearly cosmopolitan species, P. clavipes and Ptinus 

latro Fabricius, is uncertain. In the catalogue of Palaearctic 

Coleoptera, Borowski and Zahradník (2007) considered 

P. clavipes to be a junior synonym of P. latro. Philips also 

questioned the validity of P. latro. However, the types of 

both species should be examined to determine their validity 

(personal communication Dr. T. Keith Philips).

Ptinus species are not commonly encountered except in 

stored products within an indoor environment. Outdoors, 

this species may be found in association with mammal and 

bird nests. Berlese samples of nests, especially old, abandon 

nests, and use of pitfall traps are often the most effective 

way to collect Ptinus specimens outside an urban setting.

Members of Ptinus can be distinguished from other North 

American Ptininae by having the metathoracic trochanters 
General Technical Report FPL–GTR–209

12

short, with their apices not reaching the elytral margins, 

and the abdominal ventrites being subequal in width to the 

elytra when viewed ventrally (Fig. 71). Relative lengths and 

widths of both males and females of certain Ptinus species 

Ptinus bimaculatus Melsheimer

(Figs. 20, 105, 106; Map 4)

[Synonymy modified from Fall 1905, Papp 1962] 

Ptinus bimaculatus Melsheimer 1845: 308.

Ptinus frontalis Melsheimer 1845: 308.

Ptinus bimaculatus rubroapicatus Pic 1903: 183.

Ptinus bimacalatus Melsheimer; Papp 1962: 396 (lapsus 

calami).

Fall (1905) considered Melsheimer’s (1845) description of 

P. frontalis to be the male of P. bimaculatus. Similarly, Pic’s 

(1903) variation rubroapicatus was found by Papp (1962) to 

be the female of this species.

are provided where possible, as body size is strongly 

sexually dimorphic in a number of species. Other methods 

of separating males from females are also given for individual species if known.

Key to the Wisconsin Species of the Adult Ptinus

[Modified from Papp 1962 and Spilman 1991]

1 Elytra sub-parallel in males, oval in females, without black coloration; female 

 apterous; 4th abdominal ventrite distinctly shorter than 5th (Fig. 71) ............................................................................. 2

1’ Elytra elongate in both sexes, largely black in areas (Figs. 105, 109); both sexes

 winged; 4th abdominal ventrite longer, subequal to slightly shorter than the 5th .......................................................... 3

2 (1) Elytral interspaces with long, erect setae (Figs. 84, 115–118); longest erect elytral 

 setae as long as or longer than last segment of metathoracic tarsus; elytra with 

 many to at least a few recumbent scales................................................................... Ptinus villiger (Reitter) (p. 16)

2’ Elytral interspaces and striae with setae equal or subequal in length; elytral setae 

 usually shorter than last segment of metathoracic tarsus; recumbent elytral scales 

 present or completely absent........................................................................................................................................... 3

3 (2’) Pronotum usually with 2 dense rows of suberect yellowish setae, often joined 

 posteriorly, forming a U or V (Figs. 111, 113); elytral intervals with erect setae 

 subequal in length and usually uniformly angled to setae of strial punctures; 

 subbasal and subapical patches of pale, whitish scales conspicuous, especially 

 in female (Figs. 111–114) ...........................................................................................Ptinus fur (Linnaeus) (p. 14)

3’ Pronotum with erect or suberect, golden setae on either side of midline, at most

 forming 2 indistinct to moderately distinct rows, not forming a U or V; elytral

 intervals of erect setae usually more erect and slightly longer than those of strial

 punctures; subbasal and subapical spots of recumbent, whitish scales completely 

 absent, represented in female by coarse, appressed, yellowish humeral setae 

 (Figs. 107, 108)............................................................................................................... Ptinus clavipes Panzer (p. 13)

4 (1’) Each elytron with a broad, black area medially, widely interrupted at

 suture (Fig. 109)........................................................................................................ Ptinus concurrens Fall (p. 14)

4’ Broad, black area of the elytra, contiguous, not interrupted at suture 

 (Fig. 105)..........................................................................................................Ptinus bimaculatus Melsheimer (p. 12)

Capsule Description (Figs. 20, 105, 106)—Length: 2.1–

2.5 mm. Width: 0.9–1.2 mm. Integument Color: maxillary 

and labial palpi light yellowish-brown; antennae and legs 

yellowish-brown to reddish-brown; head dark reddish-black; 

pronotum black, apical margin reddish-brown to black; 

elytra mostly black, humeri and apical 0.3 of elytral disk 

orange-brown to reddish-brown; ventral surface orangebrown, reddish-brown, or black. Body Form: elongate, 

length 2.2X width. Vestiture: yellowish pubescence of head 

and pronotum moderately sparse, erect to suberect; head 

usually with 2 small patches of white, recumbent, scale-like 

setae basally (note: may be hidden by pronotum); pronotal 

setae long, with few small patches of recumbent to decumbent white, scale-like setae; scutellum densely clothed 
Death-Watch and Spider Beetles of Wisconsin

13

in white, scale-like setae; erect to suberect pubescence of 

elytra moderately sparse, yellowish to more or less blackish over the darker parts of elytral disk; each elytron with 

white, recumbent scale-like setae present in a large patch 

below humerus, partially extending into central, black area, 

forming a small round patch towards apical section of black 

elytral area; white scale-like setae forming a transverse band 

just below black elytral margin; ventral surface densely 

clothed in recumbent, yellowish to whitish setae. Head: terminal segment of each maxillary and labial palpus elongate, 

slightly rounded on lateral margins, apically pointed; antennae 11-segmented, filiform; antennae separated on frons 

by a narrow, longitudinal carina; surface densely granulate. 

Pronotum: disk rounded, distinctly constricted to form a 

basal collar; lateral margins absent; surface granulate-punctate, strongly tuberculate. Elytra: roughly parallel sided; 

humeri prominent; disk shallowly striate, with rows of punctures. Metathoracic Ventrite: not excavate for reception of 

mesothoracic legs; posteriorly with a parallel sided, moderately shallow, longitudinal sulcus; surface punctate, with 

both large and small punctures. Legs: not received in ventral 

excavations; metathoracic coxae short; prothoracic, mesothoracic and metathoracic femora club shaped, distinctly 

wider in apical half with inner margins partially grooved to 

receive the tibiae. Abdomen: with 5 ventrites; 4th ventrite 

subequal in length to the 5th.

Diagnosis—The black elytra, not interrupted at the elytral 

suture (Fig. 105), and the fourth abdominal ventrite subequal to the fifth will readily distinguish P. bimaculatus

from all other Wisconsin Ptinus species. 

Natural History—Ptinus bimaculatus is thought to breed 

in dry tree holes with accumulated dung material (personal 

communication T.K. Philips). In Wisconsin, all specimens 

of P. bimaculatus were collected in Lindgren funnel traps.

Phenology—Adult specimens of P. bimaculatus were recorded in Wisconsin from late May to mid-September.

Distribution—Ptinus bimaculatus is known from New 

York, Pennsylvania, Michigan, Mississippi, Missouri, Kansas, south into Florida, and west into Texas (Papp 1962). 

According to Fall (1905), this species is relatively rare in 

the northern States, although large numbers had been seen 

from Texas. In this study, specimens were examined from 

two Wisconsin counties; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 4)—The six specimens of P. bimaculatus examined during this study were recorded from 

the following localities: Adams Co. (3): Quincy Bluff TNC; 

Sauk Co. (3): Hemlock Draw TNC.

Ptinus clavipes Panzer

(Figs. 107, 108; Map 5)

[Synonymy modified from Papp 1962, Borowski and 

Zahradník 2007] 

Ptinus clavipes Panzer 1792: pls 24.

Ptinus testaceus Olivier 1790: 9 nec Thunberg 1784.

Ptinus brunneus Duftschmid 1825: 65.

Ptinus hirtellus Sturm 1837: 80.

Ptinus rufus Lucas 1846: 207.

Ptinus advena Wollaston 1854: 261.

Ptinus lucasii Boieldieu 1856: 636.

Ptinus testaceus Olivier is a junior primary homonym of 

Ptinus testaceus Thunberg, now considered a synonym of 

Stegobium paniceum Linnaeus, and is thus unavailable.

Capsule Description (Figs. 107, 108)—Length: 3.0–

3.7 mm. Width: 1.4–1.7 mm (♂♂ and ♀♀). Integument 

Color: head, dorsal and ventral surfaces, antennae, and legs 

uniformly light yellowish-brown to dark reddish-brown; 

maxillary and labial palpi yellowish-brown. Body Form:

elongate, subparallel, wider toward elytral apex (♂♂); 

ob-ovate (♀♀); average 2.1X longer than wide. Vestiture: pubescence yellowish; head, scutellum, and ventral 

surface with pale yellowish, moderately dense and mostly 

recumbent setae; head and ventral surface with few erect 

to suberect setae; pronotum with suberect to inclined setae 

usually forming 2 moderately distinct to indistinct longitudinal rows, each side of pronotal disk with circular patch of 

erect setae; suberect to decumbent setae of elytral intervals 

slightly longer than the mostly recumbent setae of strial 

punctures; elytral disk entirely without whitish, recumbent 

scales, humeral region with a dense to sparse patch of appressed, yellowish hairs to appressed hairs absent. Head:

terminal segment of each maxillary and labial palpus elongate, slightly rounded on lateral margins, apically pointed; 

antennae 11-segmented, filiform; antennae separated on 

frons by a narrow, longitudinal carina; vertex with a fine, 

longitudinal sulcus medially; surface obscured by pubescence. Pronotum: disk mostly rounded, distinctly constricted to form a basal collar; lateral margins absent; surface 

strongly granulate-punctate, with raised tubercles. Elytra:

humeri moderately distinct; disk shallowly striate, with 

rows of punctures. Metathoracic Ventrite: not excavate for 

reception of mesothoracic legs; short, median longitudinal 

sulcus posteriorly on disk; surface with numerous large, 

elongate punctures. Legs: not received in ventral excavations; metathoracic coxae short; prothoracic, mesothoracic, 

and metathoracic femora clavate, distinctly wider in apical 

half with inner apical margins partially grooved to receive 

the tibiae. Abdomen: with 5 ventrites; 4th ventrite short, 

distinctly shorter than 5th.

Diagnosis—Ptinus clavipes may be separated from all other 

Wisconsin Ptinus by a combination of the following characters: pronotum with erect or anteriorly-directed, golden 

setae on either side of midline, at most forming indistinct 

rows, not forming a U or V; subbasal and subapical spots 

of whitish, recumbent scales completely absent; coarse, 
General Technical Report FPL–GTR–209

14

appressed, yellowish setae present only in the humeral region or completely absent (Figs. 107, 108). Ptinus clavipes

is most likely to be confused with the similar P. fur; both 

species have similar habits, appearance and microhabitats 

(VanRyckeghem 2004).

Natural History—Ptinus clavipes, also known as the brown 

spider beetle, is thought to be omnivorous and has been 

found to feed on books, skin, feathers, dried mushrooms, excrement of rats and other animals, powdered leaves of drugs 

such as senna and jaborandi, dried fruit, grains, and sugar 

(VanRyckeghem 2004). This species is said to require six to 

nine months to complete its life cycle, although larvae can 

remain in diapause for more than 10 months depending on 

conditions (Ebeling 1978). Wisconsin specimens of P. clavipes examined during this study had no additional bionomics 

data.

Phenology—Those adult specimens of P. clavipes with label 

data were recorded in Wisconsin during late March.

Distribution—Ptinus clavipes is described as nearly cosmopolitan, occurring in North America from New York, 

New Jersey, District of Columbia, North Carolina, Georgia, 

Ohio, Wisconsin, Indiana, Illinois, Missouri, Iowa, Kansas, 

New Mexico, Arizona, and California (Papp 1962). Pellitteri 

(1977) and Pellitteri and Boush (1983) reported this species 

in Wisconsin during surveys of stored product insects in 

southern Wisconsin feed mills. During this study, specimens 

were recorded from two Wisconsin counties.

Wisconsin Records (Map 5)—The 10 specimens of 

P. clavipes examined during this study were recorded from 

the following localities: State only (2); Milwaukee Co. 

(4): Milwaukee; Rock Co. (4): Janesville. 

Ptinus concurrens Fall

(Figs. 109, 110; Map 6)

Ptinus concurrens Fall 1905: 125.

Capsule Description (Figs. 109, 110)—Length: 1.9–

2.7 mm. Width: 0.9–1.3 mm. Integument Color: maxillary 

and labial palpi light yellowish-brown; antennae and legs 

yellowish-brown to reddish-brown; head dark reddish-black; 

pronotum black; elytra mostly reddish-brown; middle of 

elytral disk to lateral margin black, broadly interrupted at 

elytral suture; apical region of elytra reddish to blackish; 

ventral surface reddish-black to black. Body Form: elongate, length 2.1X width. Vestiture: yellowish to brownish 

pubescence of head and pronotum long, thick, moderately 

dense, erect to suberect; head usually with 2 small patches 

of white to whitish-yellow, recumbent setae basally (note: 

may be hidden by pronotum); pronotal setae long, clumped 

in part, with few small patches of recumbent white, scalelike setae; scutellum and most of the reddish areas of elytra 

densely clothed in white setae, some patches extending into 

black areas of elytra; erect to suberect elytral pubescence 

moderately sparse, yellowish to whitish-yellow over reddish areas of elytral disk, mostly black over blackish areas 

of elytral disk; ventral surface densely clothed in recumbent, yellowish to whitish setae, partially obscuring surface 

sculpture. Head: terminal segment of each maxillary and 

labial palpus elongate slightly rounded on lateral margins, 

distinctly pointed apically; antennae 11-segmented, filiform; 

antennae separated on frons by a narrow, longitudinal carina; surface tuberculate. Pronotum: disk rounded, distinctly 

constricted to form a basal collar; lateral margins absent; 

surface strongly tuberculate. Elytra: roughly parallel sided; 

humeri prominent; disk shallowly striate, with rows of punctures. Metathoracic Ventrite: not excavate for reception of 

mesothoracic legs; posteriorly with a long, parallel sided, 

moderately shallow, longitudinal sulcus; surface punctate, 

with both large and small punctures. Legs: not received in 

ventral excavations; metathoracic coxae short; prothoracic, 

mesothoracic and metathoracic femora clavate, distinctly 

wider in apical half with inner margins partially grooved to 

receive the tibiae. Abdomen: with 5 ventrites; 4th ventrite 

subequal to slightly shorter than the 5th.

Diagnosis—The black elytral patches, broadly interrupted at 

the elytral suture (Fig. 109), and the fourth abdominal ventrite subequal to or slightly shorter than the fifth will readily 

separate P. concurrens from all other Wisconsin Ptinus. 

Natural History—In Wisconsin, two specimens were collected at flight intercept traps in sandy oak barrens, one in a 

Lindgren funnel trap, and one in an unbaited Townes–

Malaise trap in a dry lime prairie. 

Phenology—Adult specimens of P. concurrens were recorded in Wisconsin from early May to early June and late 

September, early October.

Distribution—Ptinus concurrens was described by Fall 

(1905) from specimens collected in northern Illinois and 

Arkansas. In this study, specimens were examined from four 

Wisconsin counties; they constitute a NEW STATE RECORD and new northern range extension as Papp (1962) 

considered this species to be restricted to the above 

localities. 

Wisconsin Records (Map 6)—The four specimens of 

P. concurrens examined during this study were recorded 

from the following localities: Adams Co. (1): Quincy Bluff 

TNC; Grant Co. (1): Dewey Heights Prairie SNA–Nelson 

Dewey State Park; Monroe Co. (1): Fort McCoy SNA; 

Sauk Co. (1): Spring Green Preserve SNA.

Ptinus fur (Linnaeus)

(Figs. 21, 22, 71, 111–114; Map 7)

[Synonymy modified from Borowski and Zahradník 2007] 

Cerambyx fur Linnaeus 1758: 393.

Ptinus rapax DeGeer 1774: 231.

Bruchus furunculus Müller 1776: 57.
Death-Watch and Spider Beetles of Wisconsin

15

Ptinus pulex Goeze 1776: 90.

Ptinus germanus Goeze 1777: 159.

Ptinus striatus Fabricius 1787: 40.

Ptinus longipes Rossi 1792: 20.

Ptinus humeralis Say 1835: 165.

Ptinus fur (Linnaeus); Linnaeus 1767: 566.

Capsule Description (Figs. 21, 22, 71, 111–114)—Length: 

2.1–3.4 (♂♂); 2.7–4.0 (♀♀) mm. Width: 0.9–1.4 (♂♂); 

1.2–1.8 (♀♀) mm. Integument Color: head, dorsal and 

ventral surfaces uniformly light yellowish-brown, reddishbrown, or reddish-black; maxillary and labial palpi yellowish-brown; antennae and legs similar in color to dorsal 

surface. Body Form: elongate, subparallel, wider toward 

elytral apex, 2.4X longer than wide (♂♂); ovate-oblong, 

2.2X longer than wide (♀♀). Vestiture: pubescence yellowish; head, scutellum, and ventral surface with pale yellowish, moderately dense and mostly recumbent setae; head and 

ventral surface with few erect to suberect setae; pronotum 

with suberect to inclined setae usually posteriorly joined, 

forming a U or V, each side of pronotal disk with circular 

patch of erect setae; suberect to decumbent setae of elytral 

intervals subequal in length to mostly decumbent setae of 

strial punctures; appressed, scale-like, white setae moderately sparse to moderately dense, especially on female, 

forming two interrupted bands on basal and apical half of 

the elytra; 5th abdominal ventrite with moderately sparse, 

inclined setae. Head: terminal segment of each maxillary 

and labial palpus elongate, slightly rounded on lateral margins, apically pointed; antennae 11-segmented, filiform, 3rd 

antennomere nearly 2X longer than 2nd (♂♂) or 3rd antennomere slightly longer than or subequal to 2nd antennomere 

(♀♀); antennae separated on frons by a narrow, longitudinal 

carina; vertex with a fine, longitudinal sulcus medially; 

surface rugose-granulate. Pronotum: disk mostly rounded, 

distinctly constricted to form a basal collar; lateral margins 

absent; surface strongly granulate-punctate, with raised tubercles. Elytra: humeri distinct; disk shallowly striate, with 

rows of punctures. Metathoracic Ventrite: not excavate for 

reception of mesothoracic legs; short, median longitudinal 

sulcus posteriorly on disk, slightly less obvious in females; 

surface with numerous large, elongate punctures. Legs: not 

received in ventral excavations; metathoracic coxae short; 

prothoracic, mesothoracic, and metathoracic femora clavate, 

distinctly wider in apical half with inner apical margins partially grooved to receive the tibiae. Abdomen: with 5 ventrites; 4th ventrite short, distinctly shorter than 5th.

Diagnosis—Ptinus fur may be separated from all other Wisconsin Ptinus by a combination of the following characters: 

dense, suberect to recumbent setae of pronotum generally 

forming a U or V (Figs. 111, 113); length of elytral interval 

setae subequal to those of strial punctures; appressed, white, 

elytral scales present; fourth abdominal ventrite shorter than 

the fifth (Fig. 71). Many specimens of P. fur possess the 

characteristic U or V shape on the pronotum, formed by two 

dense rows of setation, however, this character alone is not 

reliable for species determinations as it does not appear to 

be consistent. Ptinus fur is separated from the similar 

P. clavipes by the presence of at least some appressed, 

white scales on the elytra (Figs. 111–114), which are 

completely lacking in the latter species.

Natural History—Hatch (1961) stated P. fur, also known as 

the white-marked spider beetle, was introduced and common, found in houses, grain elevators, warehouses, sacked 

grain, and in cones of conifers. This species has also been 

reported as a pest in warehouses, granaries, museums, and 

libraries, feeding on feathers, animal skins, stuffed birds, 

herbarium specimens, stored seeds, ginger, cacao, dates, paprika, rye bread, flour, stored cereals, cottonseed in jute bags 

and insect specimens (VanRyckeghem 2004).

The majority of P. fur specimens from Wisconsin were hand 

collected (64%), with a large number of specimens collected 

crawling around in an old, unused barn, two were from a 

“jar of dead insects,” one from a “dog’s food dish,” and six 

from a dog’s water dish, near food, one from “in home,” and 

one from a cement basement of a malt house that had grain 

dust present. Specimens were also collected from Lindgren 

funnel traps, one of which was baited with ethanol and alpha 

pinene, as well as one specimen collected in a “sand pit.” An 

abandon bird’s nest on an old, unheated building covered in 

spider webs and dead insects (Berlese sample) in Dane Co. 

also provided numerous specimens (17%).

Phenology—Adults of P. fur may be found during many 

months of the year, with the majority of Wisconsin specimens collected from January to June. A large number of 

adult specimens were also collected on the outside of the 

non-heated structure mentioned previously during mid- to 

late November and a few at this location during early January. A similar observation was noted by VanRyckeghem 

(2004), who stated that adults may be found on the walls of 

cellars and unheated structures during mid-winter months. 

Distribution—The distribution of P. fur is simply described 

as cosmopolitan, commonly found infesting homes, granaries, warehouses, and museums (Papp 1962). Fall (1905) 

examined this species mostly from northeastern North 

America from Ontario, south into Massachusetts, Pennsylvania, and west into Illinois and Ohio as well as from California and Alaska. Pellitteri (1977) and Pellitteri and Boush 

(1983) encountered this species in Wisconsin during surveys 

of stored product insects in southern Wisconsin feed mills. 

During this study, specimens were recorded from 13 counties throughout Wisconsin.

Wisconsin Records (Map 7)—The 64 specimens of P. fur

examined during this study were recorded from the following localities: State only (2); Dane Co. (42): Private Property–Town of Blue Mounds; Sun Prairie; UW Lakeshore 

Nature Preserve–Picnic Point; Dodge Co. (1): Beaver Dam; 

Door Co. (2): No other locality data; Jefferson Co. 
General Technical Report FPL–GTR–209

16

(1): Waterloo; Manitowoc Co. (6): Cleveland; Marinette 

Co. (1): Middle Inlet: E Hwy 141–E Trellis Lane; Milwaukee Co. (2): Milwaukee; Portage Co. (1): Stevens Point; 

Sauk Co. (1): Hemlock Draw TNC; Shawano Co. 

(1): 5 mi. S Bonduel; Walworth Co. (1): 1 mi. S Darien; 

Waupaca Co. (1): Waupaca; Winnebago Co. (2): Oshkosh.

Ptinus villiger (Reitter)

(Figs. 84, 115–118; Map 8)

[Synonymy modified from Borowski and Zahradník 2007] 

Bruchus villiger Reitter 1884: 311.

Ptinus villiger (Reitter); Seidl 1891: 545.

Ptinus balticus Iablokoff-Khnzorian and Karapetyan 1991: 

48.

Capsule Description (Figs. 84, 115–118)—Length: 2.2–

3.1 (♂♂); 2.8–3.6 (♀♀) mm. Width: 1.0–1.2 (♂♂); 1.3–

1.7 (♀♀) mm. Integument Color: head, dorsal and ventral 

surfaces uniformly light yellowish-brown, reddish-brown, 

or reddish-black; pronotum and elytral apex sometimes 

darker than remainder of dorsal surface; maxillary and labial 

palpi yellowish-brown; antennae and legs yellowish-brown 

to reddish-brown. Body Form: elongate, subparallel, 2.4X 

longer than wide (♂♂); ovate-oblong, 2.2X longer than 

wide (♀♀). Vestiture: pubescence yellowish; head, scutellum, and ventral surface with pale yellowish, moderately 

dense and mostly recumbent setae; pronotum with erect to 

inclinate setae forming indistinct parallel rows on either side 

of midline, each side of pronotal disk with circular patch of 

erect setae basally; long, erect hairs of elytral intervals alternating with decumbent to recumbent setae of strial punctures; appressed, scale-like, white setae sparse to moderately 

dense, forming two strongly interrupted bands on basal and 

apical halfs of the elytra; 5th abdominal ventrite with sparse, 

inclinate setae. Head: terminal maxillary palpomeres elongate, slightly rounded on lateral margins, apically pointed, 

terminal segment of each labial palpus similar; antennae 

11-segmented, filiform, 3rd antennomere nearly 2X longer 

than 2nd (♂♂), or 2nd and 3rd antennomeres subequal in 

length (♀♀); antennae separated on frons by a narrow, longitudinal carina; surface granulate-punctate. Pronotum:

disk rounded, distinctly constricted to form a collar basally; 

lateral margins absent; surface strongly granulate-punctate, 

with raised tubercles. Elytra: humeri distinct; disk shallowly striate, with rows of punctures. Metathoracic Ventrite: not excavate for reception of mesothoracic legs; short, 

median longitudinal sulcus posteriorly on disk; surface with 

numerous large, elongate punctures. Legs: not received in 

ventral excavations; metathoracic coxae short; prothoracic, 

mesothoracic, and metathoracic femora clavate, distinctly 

wider on apical half with inner margins partially grooved to 

receive the tibiae. Abdomen: with 5 ventrites; 4th ventrite 

short, distinctly shorter than 5th.

Diagnosis—Ptinus villiger may be separated from other 

members of Wisconsin Ptinus by a combination of the 

following characters: long, erect setae of elytral intervals 

as long as or longer than the terminal segment of the metathoracic tarsus (Fig. 84); elytra with appressed, white scales 

present on the elytra (Figs. 115–118); fourth abdominal 

ventrite distinctly shorter than the fifth. The erect elytral 

setae will readily separate this species from both males and 

females of P. fur. Elytral setation of P. villiger may resemble 

that of P. clavipes, from which it may be distinguished by 

the presence of at least a few, but sometimes many appressed, white elytral scales.

Natural History—Ptinus villiger, also known as the hairy 

spider beetle (VanRyckeghem 2004), has been considered a 

serious pest of cereal products in Canada since 1915 (Hatch 

1961) and has been known to infest flour, farina, corn meal, 

and wheat (VanRyckeghem 2004). Adults emerge in the 

spring, after which females lay eggs on or in food debris, 

with larvae pupating within three months (VanRyckeghem 

2004). Control of P. villiger in warehouses may involve application of insecticides to floors and walls to kill insects 

before they are able to reach stored food products (VanRyckeghem 2004). Radinovsky (1957) examined the development of P. villiger given different larval food materials 

and maintained at various temperatures and relative humidity levels, and found temperature to have the most significant 

effect on development followed by food materials.

In Wisconsin, 38% of specimens were hand collected, the 

other 62% had no other collection data. Hand-collected 

specimens were from bags of old feed stored in a bin in an 

old, unused barn, on the window of the barn, or crawling 

on the barn wall. Four specimens were found in a “food 

packet,” and one from inside a house. 

Phenology—Adult specimens of P. villiger were recorded 

in Wisconsin from within heated/unheated structures during mid-April to early June. Other records, which do not 

specify if the specimen was found indoors or outdoors, were 

recorded from mid-March, mid- to late April, late June, late 

July, early September, and early November.

Distribution—In North America P. villiger is found in the 

northern parts of the United States and the southern parts 

of Canada, from Newfoundland to British Columbia (Papp 

1962), south into Washington, Nebraska, and Pennsylvania 

(Fall 1905). This species is also thought to be common in 

Europe, east into Asia (Papp 1962). Fall (1905) recorded 

this species from Bayfield, Wisconsin, while Pellitteri 

(1977) and Pellitteri and Boush (1983) encountered it in 

Wisconsin during a survey of stored product insects in 

southern Wisconsin feed mills. During this study, specimens 

were recorded from seven Wisconsin counties.

Wisconsin Records (Map 8)—The 45 specimens of P. villiger examined during this study were recorded from the 

following localities: State only (4); Dane Co. (13): Oregon; 

Private Property–town of Blue Mounds; Dodge Co. 

(13): Beaver Dam; Eau Claire Co. (4): Katt Rd– Fall 
Death-Watch and Spider Beetles of Wisconsin

17

Creek; Milwaukee Co. (1): Milwaukee; Shawano Co. 

(1): 8 mi. SW Shawano; Walworth Co. (4): Waits Rest. 

(Restaurant?); Winnebago Co. (5): 1 mi. W Oshkosh; 

2 mi. NW Oshkosh; 2 mi. W Oshkosh; 3 mi. N Oshkosh; 

Oshkosh.

Subfamily Eucradinae

Eucradinae has undergone numerous nomenclatural modifications since its inception. LeConte (1861) is credited with 

the subfamily name for placing the genus Eucrada in the 

tribe Eucradini under the subfamily Ptininae. LeConte and 

Horn had both included Hedobia and Eucrada as members 

of the Ptininae in their classification based on the proximate insertion of the antennae on the head (Fall 1905). Fall 

(1905) recognized that Hedobia and Eucrada deviated from 

typical ptinine morphology based on the palpal formation, 

apically bidentate mandibles, absence of a prosternal process separating the prothoracic coxae, non-clavate femora, 

stout tarsi with broadly triangular terminal tarsomere, metatarsus with with divaricate claws, and subequal abdominal 

segments. Therefore, he removed these genera from Ptininae and placed them in Anobiinae (Fall 1905). Subsequent 

authors included the members of this subfamily in the 

Hedobiinae, until this name was synonomyzed as a junior 

synonym of Eucradinae, which has priority if the genus Eucrada is included (Lawrence and Newton 1995). Currently, 

North American Eucradinae north of Mexico includes three 

genera and six species (Philips 2002). Eucrada humeralis

(Melsheimer) is the only species found in Wisconsin as well 

as the sole representative of the subfamily for the state.

Eucradines closely approach the anatomy of certain Ptininae 

and are therefore thought to have evolved from a common 

ancestor (Crowson 1967, White 1971a). This is supported 

by the position of the antennal insertion between the eyes, 

the absence of prothoracic lateral margins (Figs. 120–122), 

and the elongate-cylindrical body form (White 1971a). The 

filiform antennae in both sexes in Hedobia also support 

this hypothesis (Fall 1905). In a recent study examining the 

phylogenetic relationships in Ptinidae s.l., Philips (2000) 

evaluated the relationship between Ptininae and Eucradinae, 

proposing the Ptininae to be a sister taxon either to members 

of Eucradinae or to all other Ptinidae auctorum. His study 

also supports the possibility of Eucradinae as a sister group 

to the remaining Ptinidae s.l. subfamilies (Philips 2000). 

Genera within Eucradinae are wood borers, with larvae 

known to tunnel between the bark and wood of mainly dead 

hardwood trees (Rozen 1957, White 1962a, 1982). Quercus

species are most commonly listed as larval food (White 

1982).

Species of Eucradinae can be distinguished from all other 

Ptinidae by a combination of the following characters: front 

of head without narrow ridge over base of antennae; pronotum laterally rounded, without even a partial margin 

(Figs. 120–122); metathoracic coxae not distinctly grooved 

for reception of femora (extracted in part from Philips 

2002). Preparation of members of this subfamily for identification is rather straightforward, as they are not contractile 

and generally die with the necessary structures exposed. 

Genus Eucrada LeConte

[Synonymy modified from Pic 1912a, White 1974, 1982]

Type Species: Hedobia humeralis Melsheimer 1845: 

310 (by monotypy). 

Eucrada LeConte 1861: 202.

Crichtonia Abdullah 1967: 26 (a fossil genus). 

In North America, north of Mexico, Eucrada is comprised 

of two species: Eucrada humeralis (Melsheimer) and Eucrada robusta Van Dyke. Eucrada humeralis is widely distributed throughout much of the Eastern United States and is 

the only species found in Wisconsin.

Males and females of Eucrada may be easily separated 

based on their sexually dimorphic antennae. The males have 

pectinate antennae (Figs. 24, 119, 120), whereas the females 

have rather strongly serrate antennae (Figs. 25, 121, 122).

Eucrada humeralis (Melsheimer)

(Figs. 24, 25, 119–122; Map 9)

[Synonymy modified from White 1982]

Hedobia humeralis Melsheimer 1845: 310.

Eucrada humeralis (Melsheimer); LeConte 1861: 452.

This species was first described as Hedobia humeralis, but 

was later moved to Eucrada based on the sexually dimorphic antennal forms, which are not seen in Hedobia 

(LeConte 1861, Fall 1905). 

Capsule Description (Figs. 24, 25, 119–122)—Length:

3.9–5.5 mm. Width: 1.5–2.2 mm. Integument Color:

mostly dull black; mouthparts reddish-brown; antennae 

mainly dull black; head reddish-black; disk of pronotum 

orange except basal and apical margins; elytra dull black 

with elytral humeri orange; legs reddish-black; abdomen 

dull black. Body Form: robust, moderately elongate, 

2.5X longer than wide. Vestiture: head with dense, more or 

less recumbent, light grey pubescence; pronotum densely 

covered with orange pubescence which becomes lighter laterally; elytra with strial margins conspicuously pubescent, 

humeral interval a little more conspicuously cinereously pubescent, appearing as a narrow longitudinal stripe; scutellum 

and abdomen densely clothed with a light grey pubescence. 

Head: antennae 11-segmented, pectinate (♂♂), strongly 

serrate (♀♀); eyes small, separated by nearly 3X their vertical diameter, highly convex, prominent, visible dorsally. 

Pronotum: laterally rounded, without even a partial margin 

at base; disk obtusely elevated; surface granulate. Elytra:

rough; rows of punctures coarse and somewhat irregular, 

especially toward the suture; intervals narrow, feebly convex. Metathoracic Ventrite: not excavate for reception of 

mesothoracic legs; with a narrow and shallow longitudinal 

sulcus posteriorly. Legs: metathoracic coxae not grooved 
General Technical Report FPL–GTR–209

18

for reception of the femora; tibiae terminating in two spurs, 

those of the female comparable in size, in the male, the inner spur is enlarged and the smaller outer spur is in close 

approximation. Abdomen: with 5 ventrites.

Diagnosis—Eucrada humeralis may be separated from all 

other Wisconsin Ptinidae by the sexually dimorphic serrate 

(female) (Figs. 25, 121, 122) or pectinate (male) (Figs. 24, 

119, 120) antennae, the pronotum and humeral region with 

orange coloration, and the dull black elytra (Figs. 119–122). 

The absence of lateral pronotal margins (Figs. 120–122) is 

also diagnostic for the genus and species in Wisconsin. 

Natural History—Larvae bore in the bark or between bark 

and wood of dead or dying oak and beech trees (Champlain and Knull 1922, White 1962a, White 1982). Adults 

can also be found on the trunks or branches of these trees 

(White 1962a). Rozen (1957) published detailed biological 

notes on the life history of E. humeralis, in which he commented on the coexistence of pupae and mature and early 

stage larvae in one tree, suggesting that there may not be a 

definitive adult emergence period. Larval burrows averaged 

about four inches in length divided between the bark and the 

wood (Rozen 1957). Because the larvae were not found to 

burrow deeper into the wood, Rozen (1957) concluded this 

species would most likely not be of economic importance. 

The pupal casing differs from that of most other Ptinidae in 

that it is constructed of “threadlike strands of silk, presumably from anal secretions,” rather than mainly from debris 

and fecal material (Rozen 1957). This is similar to the silken 

cocoon constructed by members of the subfamily Ptininae; 

however, debris and particles of food generally adhere to the 

outer surface of the casing (Ebeling 1978). A complete larval description is provided by Böving (1954).

During this survey larvae of E. humeralis were collected 

from beneath the bark of a dead standing Quercus rubra tree 

at the LWRSGA Avoca Unit in Iowa County, Wisconsin, on 

30 April 2007. The tree maintained only half its bark, which 

was the only side shown to contain the beetles. Larvae were 

collected and kept in a small petri dish packed tightly with 

pieces of bark from the originating tree. Adult emergence 

was noted on the 14 May 2007. In Wisconsin, adults of E. 

humeralis were most frequently recovered from Lindgren 

funnel traps and flight intercept traps. One specimen was 

collected crawling on the trunk of a live tree in an area of 

both hardwoods and softwoods. 

Phenology—Adult specimens of E. humeralis were recorded in Wisconsin from mid-May to late June.

Distribution—Eucrada humeralis has been recorded from 

much of the eastern United States from South Carolina, 

north into Kentucky, Ohio, Pennsylvania, Michigan and into 

Canada (Fall 1905, White 1982). In this study, specimens 

were examined from seven Wisconsin counties; they constitute a NEW STATE RECORD and new northwestern 

range extension of the known distribution for the species.

Wisconsin Records (Map 9)—The 36 specimens of 

E. humeralis examined during this study were recorded 

from the following localities: Adams Co. (22): Quincy 

Bluff TNC; Columbia Co. (4): Rocky Run SNA; Iowa Co.

(1): LWRSGA Avoca Unit; Jackson Co. (2): Black River 

State Forest–Castle Mound Pine Forest; Menominee Co. 

(1): Private Property–Legend Lake–Spirit Island Road; 

Monroe Co. (5): Fort McCoy SNA; Wood Co. (1): Wood 

County State Wildlife Area. 

Subfamily Ernobiinae

Pic (1912a) erected Ernobiinae for genera previously included in Fall’s (1905) Dryophilini with the exception of 

Paralobium Fall. White (1962a, 1971a) maintained Fall’s 

classification, elevating the tribe to subfamilial status. Later, 

White (1974) adopted a classification more closely resembling that of Pic (1912a), with 14 genera included in Ernobiinae, including all those assigned by Pic (1912a). 

Larvae of Ernobiinae bore beneath bark or into the wood of 

dead or dying softwoods and hardwoods, and therefore may 

damage woodwork or structural wood in buildings (White 

1982). Some species bore into cones of conifers (Ruckes 

1957). Ernobius bicolor White was found to feed on old 

cones that remained on black spruce trees (Picea mariana

(Miller)), thereby interfering with the tree’s ability to reestablish especially after harvest or fire (White 1983a). Other 

larval food materials include weed stems, galls, dried flowers, and twigs of avocado (White 1982).

North American Ernobiinae north of Mexico contains eight 

genera and 50 species (Philips 2002), including Ernobius 

youngi Arango described in 2009 from the results of this 

study. Xestobium Motschulsky, Utobium Fall, and Ernobius

Thomson may occur in Wisconsin, although during the 

course of this study only members of Ernobius were collected from the state. Xestobium rufovillosum (De Geer), 

known as the true “Deathwatch beetle,” has been recorded 

from Illinois, and is therefore included in the key to genera 

due to its relatively cosmopolitan distribution. Likewise, 

Utobium elegans (Horn) may also be found in Wisconsin as 

it is generally distributed throughout much of the northern 

United States. The key presented below closely resembles 

that of Philips (2002) as adult specimens of Xestobium and 

Utobium were not obtained for examination during this 

survey.

Species of Ernobiinae are distinguished from all other 

Wisconsin Ptinidae by a combination of the following characters: elongate body shape; prothoracic ventrite inflated, 

causing the ventral surface to appear convex or flat 

(Fig. 87); legs not received in thoracic cavities (Fall 1905, 

White 1971a, Philips 2002). Curation of specimens of Ernobiinae prior to identification is generally unnecessary; however, the antennae should be brought out so as to be able to 

compare the lengths of the various antennal segments, and 

the prothoracic legs should be pulled away from the body, 

exposing the prothoracic coxae. 
Death-Watch and Spider Beetles of Wisconsin

19

Key to the Wisconsin Genera of Adult Ernobiinae

[Modified from Philips 2002]

1 Prothoracic coxae, prominent, touching to narrowly separate......................................................................................... 2

1’ Prothoracic coxae, less prominent, separated by a prosternal process ........................................................................... 3

2 (1) Prothoracic ventrite anterad coxae about 0.6X coxal diameter, prothoracic coxae very 

 narrowly separated......................................................................................................................Xestobium (in part)

2’ Prothoracic ventrite anterad coxae 0.3–0.5X coxal diameter, prothoracic coxae touching...................Ernobius (p. 19)

3 (1’) Antennal segments 4–8 subequal in length; pubescence of dorsal surface predominantly 

 golden, dull yellowish or whitish...............................................................................................Xestobium (in part)

3’ Antennal segments 4–8 unequal, segments 5 and 7 broader and distinctly longer than others;

 pubescence white, brown, black, and (frequently) orange..................................................................................Utobium

Genus Ernobius Thomson

[Synonymy modified from White 1962a, 1974, 1982, 

Philips 2002]

Type Species: Dermestes mollis Linnaeus 1758: 355.

Ernobius Thomson 1859: 88.

Conophoribium Chevrolat 1861: 391.

Philoxylon LeConte 1861: 205. 

Dryophilus LeConte 1861: 205.

Liozoum Mulsant and Rey 1863: 30, 31, 92.

Conopheribium Chevrolat; Chevrolat 1864: xvii 

(lapsus calami).

Liozum Mulsant and Rey; Mulsant and Rey 1864: 145 

(lapsus calami).

Conoploribium Chevrolat; Pic 1912a: 80 (lapsus calami).

Liozuom Mulsant and Rey; Gardiner 1953: 3 (lapsus 

calami).

Fall (1905) listed 22 species in his key to Ernobius, 12 of 

which were newly described in his revision. Included in 

Ernobius were members of Episernus, a genus Fall synonomyzed as “doubtfully distinct from Ernobius.” White 

(1969c) re-established Episernus based on the following 

characters: antennae 10-segmented, pronotum with distinct 

lateral margins only basally, prothoracic ventrite anterad 

the coxae 0.5–0.75X coxal diameter, and first tarsomere 

of metathoracic legs as long as the following three segments combined. Episernus contains two mostly western 

North American species, Episernus champlaini (Fisher) and 

Episernus trapzoideus (Fall), both of which were described 

in Ernobius. 

Currently, 31 species of Ernobius are known from North 

America as listed by White (1982), with the exception of 

Ernobius bicolor White, which was described later from 

specimens collected throughout the island of Newfoundland 

(White 1983a, Philips 2002) and E. youngi described as a 

result of the present survey (Arango 2009). Three species of 

Ernobius have been collected in Wisconsin to date, although 

six species may occur and are therefore included in the key. 

Specimens of Ernobius are uncommon in collections, and 

when found they are generally collected under bark or 

in conifer cones or at UV light (White 1982). Relatively 

few species of Ernobius in North America are considered 

economically significant on pine materials, although a few 

have been shown to be problematic. As mentioned above,

E. bicolor affects the ability of P. mariana to re-establish 

(Schooley 1983, White 1983a). Ernobius mollis, also known 

as the “pine bark anobiid” or “pine knot borer,” is a common European species thought to have been introduced into 

the eastern United States (Fall 1905, White 1962a). This 

species, although not considered a serious pest, can damage 

cut or fallen pine trees with their bark intact, thereby reducing the quality of lumber produced (Craighead 1950). In the 

United States, E. mollis has occasionally been found to damage pine and spruce flooring (Craighead 1950). Ernobius 

punctulatus (LeConte), known from western North America, 

has been found to destroy or weaken shoots of young pines 

(Ebeling 1978).

Ernobius species can be distinguished from all other Wisconsin Ptinidae by the following combination of characters: 

antennae 11-segmented with an elongate, three-segmented 

club (Fig. 26), lateral margins of pronotum complete, prothoracic ventrite convex to flat, not excavate (Fig. 87), 

prothoracic coxae contiguous and elytra without striae 

(Fig. 123–128) (extracted in part from Philips 2002). The 

antennal club and structure of the sixth abdominal ventrite 

are sexually dimorphic in Ernobius. On average, males have 

the last three antennal segments slightly more elongate than 

females, in addition to having the last abdominal ventrite 

emarginate, although this is not true for all Ernobius species 

(Fall 1905).

This genus is in need of major revision as no comprehensive key to North American species exists. Recent work on 

Ernobius includes a revision of the Iberian species (Español 

1992) and a revision of the Palearctic species (Johnson 

1975, Novoa and Baselga 2000). Fall’s (1905) revision 
General Technical Report FPL–GTR–209

20

represents the last major publication on North American 

Ernobius and is not without problems. Most couplets refer 

only to the comparative lengths of male antennal segments 

with no indication of how to determine female specimens, 

although certain species, such as Ernobius opicus Fall, 

were described from only females. In addition, dorsal surface sculpture and integument color are frequently used to 

separate species, both of which are difficult to distinguish if 

representative specimens are not available for comparison. 

Future work should involve genitalic dissections of males 

and comprehensive descriptions of both males and females. 

Key to the Wisconsin Species of Adult Ernobius

[Modified from Fall 1905 and White 1962a]

1 Ninth antennomere shorter than three preceding antennomeres combined.............................................. mollis Linnaeus

1’ Ninth antennomere longer than three preceding antennomeres combined (Figs. 26, 123, 124, 126) .............................. 2

2 (1’) Each elytron with a distinct, longitudinal carina running nearly 0.75X the length 

 of the disk (Figs 127, 128)....................................................................................................... youngi Arango (p. 22)

2’ Elytra without longitudinal carina .................................................................................................................................... 3

3 (2’) Pronotum and elytra nearly uniformly brownish-yellow (Figs. 125, 126); pronotum 

 usually with a fine, narrowlongitudinal line devoid of setae ...........................................granulatus LeConte (p. 21)

3’ Pronotum mostly dark brown or blackish, without narrow longitudinal line; elytral color 

 variable.............................................................................................................................................................................. 4

4 (3’) Elytra and pronotum nearly uniformly dark brown to blackish; length 4.8–5.5 mm ..............................lacustris Fall

4’ Elytra lighter, usually brownish-yellow; <4 mm in length ............................................................................................... 5

5 (4’) Eyes small, separated by 2.0–2.75X the vertical diameter of the eye when viewed from 

 the front....................................................................................................................................... luteipennis LeConte

5’ Eyes large, separated by 1.2–1.7X the vertical diameter of the eye when viewed from the 

 front...........................................................................................................................................filicornis LeConte (p. 20)

Because members of this genus are uncommonly encountered, the following key includes three species that have 

not yet been found in Wisconsin but may occur in the State. 

Ernobius mollis was said to be relatively common from the 

coastal region of Maine to Virginia (White 1962a) and has 

been found as far northwest as Ontario, Canada (Fall 1905, 

White 1982). Ernobius lacustris Fall may occur in Wisconsin as it has been collected from Cook County, Minnesota, 

as well as from Marquette and Ann Arbor, Michigan. Ernobius luteipennis LeConte is also included in the key because 

it has been widely collected across much of the eastern 

United States.

Ernobius filicornis LeConte

(Figs. 26, 123, 124; Map 10)

Ernobius filicornis LeConte 1879: 517.

Capsule Description (Figs. 26, 123, 124)—Length: 2.1–

2.7 mm. Width: 0.8–1.0 mm. Integument Color: maxillary and labial palpi yellowish to reddish-yellow; antennae yellowish to brownish; head, pronotum, metathoracic 

ventrite, and abdomen dark reddish-brown to blackish; legs 

yellowish to reddish-yellow; elytra yellowish to dark reddish-brown. Body Form: elongate, 2.6X longer than wide.

Vestiture: pubescence yellowish, fine, completely recumbent. Head: terminal segment of maxillary palpi elongate, 

nearly parallel-sided; eyes large, separated by 1.2–1.7X the 

vertical diameter of the eye when viewed from the front; 

antennae 11-segmented, clubbed, 9th antennomere longer 

than 3 preceding segments combined (♂♂ & ♀♀), about 

as long as 6 preceding segments combined (♂♂); surface 

finely granulate-rugose. Pronotum: moderately rounded 

dorsally; hypomera mostly flat to slightly convex ventrally, 

not at all excavate; lateral pronotal margins complete; dorsal 

surface finely granulate-rugose. Elytra: slightly wider than 

width of pronotum; surface irregularly punctate, not at all 

striate. Metathoracic Ventrite: not excavate for reception 

of mesothoracic legs; medially with a nearly parallel-sided, 

moderately shallow sulcus, 0.5–0.75X length of disk, terminating before anterior margin. Legs: not received in ventral 

excavations; prothoracic coxae contiguous; 1st tarsomere 

of all legs elongate; metathoracic coxae grooved to receive 

metathoracic legs. Abdomen: with 6 ventrites; 1st ventrite 

not at all grooved for metathoracic legs; 6th ventrite smaller.

Diagnosis—Ernobius filicornis may be distinguished from 

all known and potential species of Wisconsin Ernobius

by the following combination of characters: eyes large, 
Death-Watch and Spider Beetles of Wisconsin

21

separated on the front by slightly more than their vertical 

diameter, to slightly more than 1.5X their vertical diameter; 

ninth antennal segment of the male equal to the six preceding segments combined (Figs. 26, 123); head and pronotum 

generally darker when compared with the elytra (Fig. 123, 

124); small, 2–3 mm size. 

Ernobius filicornis is most likely to be confused with specimens of E. luteipennis, partially because both Fall (1905) 

and White (1962a) used integument color for species separation in their taxonomic keys. More specifically, specimens 

of E. filicornis and E. lacustris were separated from E. 

granulatus and E. luteipennis by the elytra being black or 

dark brown. Fall (1905) described E. filicornis as “piceous,” 

E. granulatus as “rufotestaceous,” and E. luteipennis as 

having the “head and prothorax black or piceous, the elytra 

testaceous in the male; head and prothorax usually a little 

darker than but sometimes con-colorous with the elytra in 

the female.” However, specimens I examined from the Ohio 

State Insect Collection, likely determined by White, seem to 

be more variable in color than accounted for in both Fall’s 

(1905) and White’s (1962a) work. This may lead to misidentifications if teneral specimens are collected, or if there is no 

way to compare them with similar species. The distance between the compound eyes compared to their vertical diameter when viewed from the front proved useful in separating 

E. filicornis from E. luteipennis and was discovered to be 

the main character for their separation in this work.

Natural History—Little has been published on the biology 

of E. filicornis. In Wisconsin, four specimens were obtained 

from material collected during a study examining red pine 

pocket mortality. One specimen came from a Lindgren funnel and two from flight intercept traps. An additional specimen was collected at Hg/UV at night. 

Phenology—Adults of Wisconsin E. filicornis were 

recorded from mid-June to late July.

Distribution—In North America, E. filicornis has been 

recorded from Massachusetts, Virginia, and Ohio (White 

1982) as well as from the Maritime Provinces of Canada 

(Majka 2007b). During this study, specimens were examined from four Wisconsin counties; they constitute a NEW 

STATE RECORD and new northwestern range extension 

for the known distribution of this species. 

Wisconsin Records (Map 10)—The five specimens of E. 

filicornis examined during this study were recorded from 

the following localities: Jackson Co. (1): Black River Falls; 

LaCrosse Co. (1): West Salem; Vilas Co. (1): Northern 

Highland American Legion State Forest; Waupaca Co. 

(2): B. Schellpfeffer Property; J. Baker Property.

Ernobius granulatus LeConte

(Figs. 125, 126; Map 11)

Ernobius granulatus LeConte 1865: 225.

Capsule Description (Figs. 125, 126)—Length: 2.7 mm. 

Width: 1.0 mm. Integument Color: brownish-yellow, 

shining throughout; maxillary and labial palpi, antennae, 

and legs light yellowish to yellowish-brown; ventral 

surface somewhat darker brown. Body Form: elongate, 

2.6X longer than wide. Vestiture: pubescence yellowish, 

fine, completely recumbent. Head: terminal segment of 

maxillary palpus elongate; eyes large, separated by 1.6X the 

vertical diameter of the eye when viewed from the front; 

antennae 11-segmented, clubbed, 9th antennomere longer 

than 3 preceding segments combined (♂♂ & ♀♀); surface 

finely granulate-rugose. Pronotum: with a fine, narrow, longitudinal line devoid of setae medially; moderately rounded 

dorsally; hypomera mostly flat to slightly convex ventrally, 

not at all excavate; lateral pronotal margins complete; dorsal surface finely granulate-rugose. Elytra: equal in width 

to that of pronotum; surface irregularly punctate, not at all 

striate. Metathoracic Ventrite: not excavate for reception 

of mesothoracic legs; medially with a shallow sulcus 0.5X 

length of the disk. Legs: not received in ventral excavations; 

prothoracic coxae contiguous; metathoracic coxae grooved 

to receive metathoracic legs. Abdomen: with 6 ventrites; 

1st ventrite not at all grooved for metathoracic legs; 6th ventrite smaller, slightly emarginate.

Diagnosis—Ernobius granulatus may be distinguished from 

all other Wisconsin Ernobius species by the ninth antennomere being longer than the combined length of antennomeres 6–8 and by the uniformly yellowish-brown to light 

reddish-brown color (Fig. 125, 126). Teneral specimens of 

other Ernobius species may accidentally be mistaken for 

E. granulatus because this species closely resembles other 

species in this genus and is only distinguished from them by 

integument color. 

Natural History—Larvae were described by Böving (1954) 

for specimens determined as “probably E. granulatus” 

collected from Pinus caribeae and “in dying tip of Pinus 

palustris.” It has also been recorded in conifer cones (White 

1982) and infesting stored pine cones (Craighead 1950). 

Frost (1975) collected specimens of E. granulatus during a 

survey of insects taken at light traps from the Archbold Biological Station in Florida. Davis and Leng (1912) reported 

several specimens from a study of insects occurring on a 

recently felled long leaf pine tree (P. palustris Miller). In 

Wisconsin, the single specimen of E. granulatus collected 

had no natural history data.

Phenology—The adult specimen of E. granulatus was recorded in Wisconsin during late August.

Distribution—Ernobius granulatus is widely distributed 

in the eastern United States; northeast from Massachusetts, 

New York, and Pennsylvania, southeast into Florida and 

Georgia, and as far southwest as Texas (White 1982). This 

species has also been recorded from the Maritime Provinces 

of Canada (Majka 2007b). In this study, the single specimen 

collected constitutes a NEW STATE RECORD and new 

northwestern range extension for the known distribution of 

this species.
General Technical Report FPL–GTR–209

22

Wisconsin Records (Map 11)—The only specimen of 

E. granulatus examined during this study was recorded 

from the following locality: Waushara Co. (1): Plainfield.

Ernobius youngi Arango

(Figs. 127, 128; Map 12)

Ernobius youngi Arango 2009: 353.

Ernobius youngi was described from a single female specimen in honor of Dr. Daniel K. Young, who has inspired 

many in the study of Coleoptera.

Capsule Description (Figs. 127, 128)—Length: 3.3 mm. 

Width: 1.4 mm. Integument Color: light yellowish-brown 

to orange-brown throughout; maxillary and labial palpi yellowish; abdomen slightly darker; dorsal surface shining. 

Body Form: elongate; 2.3X longer than wide. Vestiture:

pubescence yellowish, moderately dense, completely recumbent. Head: terminal segment of maxillary palpi elongate, 

2.6X longer than wide; eyes small, separated by 2.0X the 

vertical diameter of the eye when viewed from the front; 

antennae 11-segmented, clubbed, 9th antennomere equal 

in length to 5 preceding antennomeres combined; surface 

punctate, margin of punctures raised. Pronotum: disk moderately rounded, 1.7X wider than long at widest diameter; 

lateral margins smooth, expanded and broadly reflexed; 

surface punctate with margins of punctures raised, partially 

incomplete posteriorly towards center of disk. Elytra:

slightly narrower than pronotum at base; surface punctate, 

margin of punctures raised, not at all striate. Metathoracic 

Ventrite: not excavate for reception of mesothoracic legs; 

medially with a shallow, longitudinal and darkly pigmented 

sulcus extending less than 0.5X length of disk from posterior margin; surface mostly rugose, smoother medially along 

posterior margin. Legs: not received in ventral excavations;

prothoracic coxae contiguous; metathoracic coxae shallowly 

grooved to receive metathoracic legs. Abdomen: with 

6 ventrites; 1st ventrite not at all grooved for metathoracic 

legs; 6th ventrite smaller and weakly emarginated apically.

Diagnosis—Ernobius youngi is easily distinguished from 

all other Ernobius species by the elytron each with a distinct 

longitudinal carina running nearly 0.75X the length of the 

disk.

Natural History—Collection methods for this specimen 

were not noted. 

Phenology—The single adult specimen of E. youngi was 

recorded in Wisconsin on 25 July 1947.

Distribution—During this study, specimens were recorded 

from a single Wisconsin county.

Wisconsin Records (Map 12)—The single specimen of 

E. youngi examined during this study was recorded from the 

following locality: Wood Co. (1): Griffith State Nursery.

Subfamily Anobiinae

Anobiinae was erected by Fleming (1821) as Anobiumedæ 

for those genera differing from Ptininae (written Ptinusidæ) by having the antennae much shorter than the length 

of the body and the metathorax nearly equal in width to 

the abdomen. Subsequent works, such as LeConte (1861) 

and Fall (1905), maintained division of Ptinidae into two 

subfamilies: Ptininae and Anobiinae. In these publications, 

the Anobiinae was further divided into tribes, which would 

later be elevated to subfamilial status in Pic’s (1912a) catalog. The genera included in Anobiinae have changed little 

since Fall’s (1905) classification, with the exception of three 

genera: Platybregmus Fisher, Falsogastrallus Pic, and Desmatogaster Knutson, which were subsequently described 

within Anobiinae. Classification used in this work follows 

such recent publications as Lawrence and Newton’s (1995) 

review of the higher taxonomy of Ptinidae as well as works 

by White (1982) and Philips (2002). 

Anobiinae contains some of the most economically important ptinid species in North America including Trichodesma 

gibbosa (Say), Nicobium castaneum (Olivier), Anobium

punctatum (De Geer), Hemicoelus carinatus (Say), Hemicoelus gibbicollis (LeConte), Hemicoelus umbrosus (Fall), 

Hadrobregmus quadrulus (LeConte), Priobium punctatum

(LeConte), Priobium sericeum (Say), as well the stored 

product pest, Stegobium paniceum (Linnaeus). Hemicoelus 

gibbicollis was reported by Furniss (1939) as potentially 

the most destructive native powder-post beetle found in the 

Pacific Coast States (Simeone 1960). Linsley (1943) also 

reported H. gibbicollis as “the most serious pest among the 

powderpost beetles in the broad sense of the term” (Ebeling 

1978). Although H. gibbicollis does not occur in Wisconsin, 

another species in the same genus, H. carinatus, is found 

frequently throughout the state and is considered the most 

common wood-damaging ptinid in eastern North America 

(White 1982). Böving (1954) described in detail the larvae 

of some of the more commonly encountered species within 

Anobiinae.

North American Anobiinae contains 19 genera and 68 species north of Mexico (White 1982, Philips 2002). Seven 

genera and 13 species are known from Wisconsin. Although 

unlikely to occur in Wisconsin, Anobium has been included 

in the generic key because it contains the cosmopolitan 

species A. punctatum, which may potentially become introduced. 

Wisconsin Anobiinae may be distinguished by a combination of the following characters: head in repose with mandibles distant from metathoracic ventrite (Figs. 129–154); 

prothoracic ventrite concave ventrally (Fig. 86), with 

complete to partially interrupted lateral margins (Figs. 130, 

132); elytra striate; pubescence distinct; and body elongatecylindrical (extracted in part from Philips 2002). Although 

members of this subfamily are not highly contractile, certain 
Death-Watch and Spider Beetles of Wisconsin

23

genera are adapted to receive either the antennae or the legs 

into grooves of the ventral surface. An important advantage 

to having the prothoracic coxae separated by a prosternal 

process is to allow the antennae to lie between them in tight 

spaces (e.g., Hadrobregmus, Hemicoelus, Oligomerus sericans (Melsheimer), Priobium). Another adaptation is in the 

structure of the metathoracic ventrite, which may be deeply 

Genus Hemicoelus LeConte

[Synonymy modified from White 1962a, 1982] 

Type Species: Anobium gibbicollis LeConte 1859: 284 

(designated by Knutson 1963: 187). 

Hemicoelus LeConte 1861: 204.

Cacotemnus LeConte 1861: 204.

Hadrobregmus (of authors, not Thomson).

Hemicoelum LeConte; Español 1971: 22 (lapsus calami).

excavate anteriorly to receive the antennal club and prothoracic tarsi (e.g., Hadrobregmus and Priobium). Proper curation of Anobiinae prior to identification involves pulling the 

antennae or the prothoracic legs away from these structures 

so that the prosternal intercoxal process and the prothoracic 

coxae are visible; the mesothoracic coxae should also be 

exposed. 

Key to the Wisconsin Genera of Adult Anobiinae

[Modified from White 1971a and Philips 2002]

1 Prothoracic coxae touching or very narrowly separated; combined length of last 3 antennal 

 segments nearly as long as, to much longer than all preceding segments combined 

 (Fig. 27)................................................................................................................................Oligomerus (in part) (p. 33)

1’ Prothoracic coxae distinctly to widely separated; length of last 3 antennal segments variable ..................................... 2

2 (1’) Combined length of last 3 antennal segments not longer than combined length of 

 preceding 5 segments (Fig. 28)........................................................................................................Priobium (p. 30)

2’ Combined length of last 3 antennal segments much longer than combined length of 

 preceding 5 segments..................................................................................................................................................... 3

3 (2’) Prosternal intercoxal process with sides converging posteriorly, more or less V-shaped; 

 punctures of elytral striae obscure, elongate, and longitudinally closed spaces............................Stegobium (p. 37)

3’ Prosternal intercoxal process parallel-sided (Fig. 86), apex truncate; punctures of elytral 

 striae not as above........................................................................................................................................................... 4

4 (3’) Tarsal claws each with a broad, basal tooth (Fig. 68)................................................................Trichodesma (p. 32)

4’ Tarsal claws simple (Fig. 69).......................................................................................................................................... 5

5 (4’) Abdominal ventrites 2, 3, and 4 with sutures distinct laterally, weak to nearly absent 

 medially (Fig. 79)................................................................................................................... Hadrobregmus (p. 29)

5' Abdominal ventrites 2, 3, and 4 with sutures distinct throughout................................................................................... 6

6 (5’) Metathoracic ventrite deeply excavate anteriorly........................................................................................Anobium

6’ Metathoracic ventrite not deeply excavate anteriorly..................................................................................................... 7

7 (6’) Abdominal ventrite 3, 1.5X length of ventrite 4 (Fig. 138); pronotum concave medially, 

 produced laterally near base (Fig. 137).....................................................................................Microbregma (p. 28)

7' Abdominal ventrite 3 sub-equal in length to ventrite 4; pronotum convex to flat medially ........................................... 8

8 (7’) Prothoracic coxae separated by 0.5X coxal diameter or less; elytral strial punctures 

 without distinct margins or fine lines; pronotum stouter (Fig. 145–152) .....................Oligomerus (in part) (p. 33)

8’ Prothoracic coxae separated by 0.5–1.0X coxal diameter; elytral strial punctures with 

 more or less distinct margins; pronotum less stout (Fig. 129–136)...................................................Hemicoelus (p. 23)

Knutson (1963) synonymized Hadrobregmus Thomson with 

Coelostethus LeConte. The North American species formerly placed in Hadrobregmus were assigned to Hemicoelus

and Cacotemnus (both previously considered synonyms of 

Hadrobregmus). White (1965) noted the differences given 

for separation of Hemicoelus and Cacotemnus, specifically 

the slight gibbosity of the prothorax, the wing venation, and 

the structure of the lateral lobe in the male genitalia, are 

unreliable, thereby proposing Cacotemnus as a synonym of 

Hemicoelus.
General Technical Report FPL–GTR–209

24

Hemicoelus includes some of the most economically significant species in North America. Hemicoelus gibbicollis

(LeConte), also known as the California deathwatch beetle, 

is a serious pest species in the Pacific coastal region (Ebeling 1978), and may be the most economically significant 

species of Hemicoelus for North America. This species has 

been found to cause extensive damage to well-seasoned 

flooring, joists, and supporting timbers of structures (Ebeling 1978). Suomi and Akre (1992) reported Pseudotsuga 

menziesii (Mirbel) Franco, Thuja plicata Donn ex D. Don, 

and Tsuga heterophylla (Rafinesque) Sargent as the most 

commonly infested building materials in structures in the 

Pacific Northwest. Seybold (2001) provided a complete list 

of wood material records utilized by H. gibbicollis. Hemicoelus carinatus is also of economic significance and is discussed further in the species description that follows. 

Controlling infestations of Hemicoelus has often focused on 

removal of infested wood material in addition to lowering 

the moisture content of the wood by increasing ventilation 

to the area where the beetles occur (Simeone 1960). If possible, stains or paints are applied to the wood surface to 

prevent oviposition by females. Less frequently, borates or 

other insecticides may be applied, which will aide in preventing future infestation but will not kill insects already 

developing in the wood. 

Species of Hemicoelus have been recorded in a variety of 

hardwood as well as softwood species, including Acer, 

Carya, Fraxinus, Fagus, Tilia, Quercus, Ulmus, Betula, Tsuga, Picea, and Pinus (White 1962a, Ebeling 1978). A more 

comprehensive list of larval food material for Wisconsin 

specimens is given for individual species below.

In North America, Hemicoelus includes seven species north 

of Mexico, four of which occur in Wisconsin (White 1982). 

Specimens of Hemicoelus have been collected at light, or 

in Lindgren, Townes–Malaise, and flight intercept traps, 

as well as by rearing infested wood material. Inspection 

of historic structures (e.g., churches and covered bridges), 

barns, and crawl spaces of older homes almost always yields 

specimens.

Members of Hemicoelus may be separated from all other 

Wisconsin Anobiinae by a combination of the following 

characters: antennae distinctly clubbed with the last three 

segments much longer than the preceding five (Figs. 33–35); 

prothoracic coxae distinctly separated by a parallel-sided 

intercoxal process (Fig. 86); pronotum not concave at center 

dorsally; elytral punctures with distinct margins (Fig. 76); 

elytral pubescence uniform in color; metathoracic ventrite 

without anterior excavation; abdominal ventrite sutures 

distinct throughout with third and fourth ventrites subequal 

in length (Figs. 73, 74) (extracted in part from Philips 2002). 

Males and females of this genus may be separated based 

on their sexually dimorphic antennae in which the antennal 

club of males is more elongate and about one half longer 

than that of females (Figs. 33, 34). Females also tend to 

be larger than males, although this character is unreliable 

(Simeone 1960). 

As has been noted for some species of Oligomerus, the 

number of antennal segments in species of Hemicoelus varies to some degree (Fall 1905, White 1962a). For example, 

H. linearis, a species synonomized with H. carinatus, has 

been shown to have either 9- or 10-segmented antennae 

(Fall 1905). Two Hemicoelus species, H. carinatus and 

H. umbrosus, are separated exclusively with respect to the 

number of antennal segments, although they are otherwise 

difficult to distinguish (see diagnosis for H. umbrosus). 

Acciavatti (1972) thought that phenology could help distinguish these two species because H. umbrosus occurs from 

early to late June and H. carinatus from late June to late 

July. In my opinion, however, the differences in seasonal 

occurrence are not separated enough to be useful. In this 

survey, H. carinatus and H. umbrosus are treated as separate 

species; genetic analysis, however, might provide further 

insight into their relationship.

Key to the Wisconsin Species of Adult Hemicoelus

[Modified in part from White 1962a and 1976b]

1 Lateral pronotal margin at least partially obliterated to weakly indicated by produced, 

 discrete granules (Fig. 132).............................................................................................................. defectus (Fall) (p. 26)

1’ Lateral pronotal margin distinct and complete throughout (Figs. 130, 134, 136) ............................................................ 2

2 (1’) Smaller, length 2.1–2.8 mm; second abdominal segment a little longer than fifth; first 

 ventral suture broadly arcuate posteriorly at middle (Fig. 74)................................................... pusillus (Fall) (p. 27)

2’ Larger, length 3.1–5.8 mm; abdomen not as above .......................................................................................................... 3

3 (2’) Antennae 10-segmented; abdomen near middle finely punctate and shiny, with little to no 

 indication of granules...............................................................................................................carinatus (Say) (p. 25)

3’ Antennae 11-segmented; abdomen near middle finely punctate and nearly always with distinct, 

 fine granulation, less shiny............................................................................................................umbrosus (Fall) (p. 27)
Death-Watch and Spider Beetles of Wisconsin

25

Hemicoelus carinatus (Say)

(Figs. 33, 34, 73, 129, 130; Map 13)

[Synonymy modified from Simeone 1960, Knutson 1963, 

White 1965, 1982] 

Anobium carinatus Say 1823: 187.

Anobium errans Melsheimer 1846: 309.

Hadrobregmus linearis LeConte 1865: 232.

Hadrobregmus carinatus (Say); LeConte 1865: 232.

Cacotemnus carinatus (Say); Knutson 1963: 178.

Hemicoelus carinatus (Say); White 1965: 113. 

Capsule Description (Figs. 33, 34, 73, 129, 130)—Length: 

3.4–6 mm. Width: 1.2–1.9 mm. Integument Color: light 

reddish-brown or orange-brown to dark reddish-brown; 

maxillary and labial palpi, and antennae generally lighter. 

Body Form: elongate, parallel, 2.9X longer than wide. 

Vestiture: pubescence yellowish, short, entirely recumbent 

on elytra and pronotum, slightly to moderately bristling on 

head. Head: antennae 10-segmented, clubbed, last 3 antennal segments longer than preceding segments combined; 

surface densely granulate. Pronotum: base subequal in 

width to the elytra; slightly gibbous; laterally rounded; lateral margins complete; moderately convergent toward apex; 

surface densely granulate. Elytra: parallel sided, converging apically; punctures moderately impressed; strongly and 

rather closely punctate striate. Metathoracic Ventrite: not 

excavate for reception of mesothoracic legs; with a moderately impressed, longitudinal sulcus posteriorly; surface 

granulate, densely punctate. Legs: not received in ventral 

excavations. Abdomen: with 5 ventrites; first ventrite suture 

straight; ventrite 2 subequal in length to 5.

Diagnosis—Hemicoelus carinatus may be separated from 

all other Wisconsin Hemicoelus by its larger size, 10-segmented antennae (Figs. 33, 34), the presence of a complete 

pronotal lateral margins, and abdominal ventrite two nearly 

equal in length to ventrite five (Fig. 73). This species closely 

resembles Hemicoelus umbrosus with the exception of the 

number of antennal segments. The relationship between the 

two species is discussed further in the diagnosis for H. umbrosus.

Natural History—Hemicoelus carinatus, the eastern deathwatch beetle, is a serious economic pest throughout eastern 

North America (Ebeling 1978). An extensive study of the 

ecology, life history, abundance, distribution, and control 

of H. carinatus was done by Simeone (1960) during his 

Ph.D. work. This species has been recorded from Fraxinus, Tilia, Acer, Fagus, and Ulmus (White 1962a, Ebeling 

1978). Simeone (1960) listed 12 hardwoods and softwoods 

as larval food for H. carinatus, stating that hardwoods are 

preferred, but softwoods may be utilized in areas of higher 

humidity. He determined the life cycle of this species to be 

completed in about one year, which is relatively rapid compared with other Anobiidae. The success and relative abundance of this species is attributed in part to their shorter life 

cycle, the wide range of acceptable larval food material, and 

their ability to develop in both hardwoods and softwoods 

(Simeone 1960). Additionally, Smith and Whitman (1992) 

noted H. carinatus will attack old as well as newly cut 

wood, which suggests a range in tolerance to various starch 

contents in wood.

Larvae of H. carinatus were described, with some uncertainty, by Böving (1954) from decaying roots of a live Tsuga

sp. Larvae of this species can cause significant damage, 

possibly resembling that caused by Lyctus spp. (Bostrichidae), to wood flooring as well as in sills, joists, and beams 

of buildings (Ebeling 1978). In Wisconsin, many old barns 

are likely to be infested, or have been infested, with this 

species, at times causing severe structural damage. Simeone 

(1960) inspected 720 farm and non-farm structures in New 

York State and reported at least 31% had at least some anobiid damage, which was likely from H. carinatus, although 

positive identification was not possible in all cases. The 

higher humidity and lack of adequate ventilation in many of 

these structures was thought to aide in the development of 

this species (Simeone 1960). Several control methods have 

been proposed to protect wooden structures from H. carinatus, the first of which involves constructing buildings so 

the wood remains ventilated and dry without accumulation 

of excessive humidity (<13% moisture content) (Simeone 

1960). It is also thought that immature stages of H. carinatus require a period of cold for development, which is why 

they are not commonly seen in heated structural lumber 

(Simeone 1960). Therefore, the use of a space heater or 

other type of centralized heating system may also aide in the 

control of this species in normally unheated areas (Simeone 

1960). The effectiveness of various parasitoids has also been 

investigated. Simeone (1960) and Cabrera et al. (2002) both 

recorded Heterospilus flavicollis (Ashmead), a braconid 

wasp, as a parasitoid of H. carinatus, although the effect of 

H. flavicollis in controlling large populations of H. carinatus

is not well documented. Various chemical insecticides and 

fumigants are sometimes used (e.g.,borates); however, many 

of these products are not able to penetrate deeply enough 

into the wood to effect the most destructive larval stage 

of H. carinatus (Simeone 1960). Painting or staining the 

exposed wooden surface is also commonly known to deter 

oviposition by H. carinatus adult females. 

Hemicoelus carinatus is perhaps the most frequently encountered wood-boring ptinid in Wisconsin structures. 

During this survey, five indoor infestations were visited in 

south-central Wisconsin. Three of the five occurred in old, 

unheated barns being used for storage, in which at least 

some of the structural wood was partially decayed. Live and 

dead adults were generally collected on or near the barns’ 

window sills. In one particular barn in Sun Prairie, the infestation had been left unchecked for so long that H. carinatus

was able to cause structural damage to some of the barn’s 

main support beams. One specimen was collected hanging 
General Technical Report FPL–GTR–209

26

from a blade of grass near a recently cut boxelder tree in 

the vicinity of one of the infested barns (Fig. 10). Another 

infestation occurred in a residence in which the homeowner 

cut down a dead hickory tree from his yard for firewood and 

stored the wood inside a porch closet. Adult beetles emerged 

nearly concurrently, filling the room with ptinids. A large 

fungal fruiting body was collected from the hickory stump 

and identified as Phellinus gilvus (Schwein.). The last infestation was inside a 115-year-old, one-room school house in 

Monticello (Fig. 7), in which the maple flooring was severely damaged by H. carinatus (Fig. 8). The floor also showed 

damage from decay fungi and excessive moisture. 

Other Wisconsin specimens were obtained at Lindgren, 

flight intercept, Townes–Malaise, and light traps, as well as 

on sticky traps and using a mercury vapor lamp. The majority of specimens were hand collected from the various infestations or sent in from indoor infestations or from cut logs/

lumber. A large series of H. carinatus, which had emerged 

from a birch tree cut one year earlier, were sent to the University Insect Diagnostic Laboratory for identification in 

early May. A number of IRCW specimens are labeled as 

follows: from “flooring,” “from sawed lumber,” “from Acer 

saccharum,” “collected on air near” and “on apple tree,” 

“under bark of large, recently fallen Quercus sp. tree limb,” 

and “in basement of home.” 

Phenology—Adult specimens of H. carinatus were recorded outdoors in Wisconsin from early May to late July, 

appearing to be most prevalent during the month of June. 

This seasonality resembles closely the emergence periods 

reported from New York State by Simeone (1960). Records 

of indoor emergences in Wisconsin have been documented 

during March, June, August, and one from December, although the label of the last record does not directly specify 

that the specimen was collected indoors. 

Distribution—Hemicoelus carinatus is widely distributed 

throughout eastern North America (Ebeling 1978), its range 

extending into the Midwestern states including Wisconsin (Simeone 1960). This species has been recorded as far 

northwest as Manitoba and Saskkatchewan and as far south 

as North Carolina (White 1982). Simeone (1960) reported 

examining museum specimens of H. carinatus from Oregon, 

Alaska, and Florida, although he stated that these records 

were most likely the result of transportation of infested 

materials. In this study, specimens were examined from 

27 counties throughout Wisconsin.

Wisconsin Records (Map 13)—The 189 specimens of H. 

carinatus examined during this study were recorded from 

the following localities: State only (2); Adams Co. (3):

Quincy Bluff TNC; Barron Co. (3): Rice Lake; Buffalo 

Co. (2): Engel Farm Property; Burnett Co. (1): Crex Meadows SWA; Clark Co. (2): Schmidt Maple Woods SNA; 

Columbia Co. (1): Rocky Run SNA; Dane Co. (80): DeForest; Madison; Nakoma Golf Course; Private Property–

Town of Blue Mounds; Private Property–Deerfield; Private 

Property–Sun Prairie–Corner Town Hall & Bailey Rd; Private Property–Sun Prairie –Woodsend Ct; Swamp Lover’s 

Inc.; No additional locality data; Dodge Co. (6): Beaver 

Dam; Door Co. (1): Sturgeon Bay; Douglas Co. (1): Brule 

River State Forest; Eau Claire Co. (1): Eau Claire County 

Forest; Florence Co. (4): Morgan Lake; Private Property; 

No additional data; Fond du Lac Co. (1): No other locality data; Green Co. (7): Monticello–Exetor Crossing Rd; 

Ward/Swartz Decatur Woods SNA; Jackson Co. (3): Black 

River State Forest–Castle Mound Pine Forest SNA; No 

other locality data; Juneau Co. (1): Lemonweir Bottomland 

Hardwood Forest SNA; Lafayette Co. (4): Wedel Property– 

~3 mi. north of Argyle; Lincoln Co. (16): Council Grounds 

State Park–Kruger Pines SNA; Merrill; Marinette Co. 

(1): Marinette County Beech Forest SNA; Oconto Co. 

(8): 4 mi. W. Soring; Rock Co. (1): Janesville; Sauk Co. 

(17): Hemlock Draw TNC; Sheboygan Co. (6): Kettle 

Moraine Red Oaks SNA; Sheboygan; Vernon Co. (8): Mt. 

Pisgah Hemlock–Hardwoods SNA; Walworth Co. (7): No 

other label data; Waupaca Co. (1): Waupaca; Wood Co. 

(1): Powers Bluff SNA.

Hemicoelus defectus (Fall)

(Figs. 131, 132; Map 14)

[Synonymy modified from White 1965, 1982] 

Hadrobregmus defectus Fall 1905: 182.

Cacotemnus defectus (Fall); Knutson 1963: 178.

Hemicoelus defectus (Fall); White 1965: 113. 

Hemicoelus defectus was described by Fall (1905) from a 

single female specimen.

Capsule Description (Figs. 131, 132) —Length: 4.5 mm. 

Width: 1.7 mm. Integument Color: Dark brown to blackish; maxillary and labial palpi, antennae, and legs reddishyellow to yellowish. Body Form: elongate, parallel, 2.7X 

longer than wide. Vestiture: pubescence yellowish, short, 

entirely recumbent. Head: antennae 10-segmented, clubbed; 

last 3 antennal segments much longer than preceding segments combined; surface granulate. Pronotum: base distinctly narrower than the elytra; compressed inward laterally 

toward apex; lateral margins incomplete, appearing partially 

granulate. Elytra: strongly and rather closely punctate-striate; punctures moderately impressed. Metathoracic Ventrite: not excavate for reception of mesothoracic legs; with 

narrow longitudinal sulcus posteriorly. Legs: not received in 

ventral excavations. Abdomen: with 5 ventrites.

Diagnosis—Hemicoelus defectus is easily separated from 

all other Wisconsin Hemicoelus by having the lateral pronotal margins partially incomplete, appearing granulate 

(Fig. 132). 

Natural History—Little is known of the natural history of 

this species. The specimen from which the original description was made is said to have been collected “on an oak 

stump in the woods” (Fall 1905). Knutson (1963) recorded 

Pinus ponderosa Lawson as a larval food for H. defectus. Of 
Death-Watch and Spider Beetles of Wisconsin

27

the two male Wisconsin specimens collected, one specimen 

was recorded “from bread like fungus,” while the other was 

obtained at UV light.

Phenology—Adult specimens of H. defectus were recorded 

in Wisconsin from mid- to late June.

Distribution—Scattered records of this species occur 

throughout the northern range of North America into 

Canada. In this study, specimens were examined from a 

single Wisconsin county; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 14)—The two specimens of 

H. defectus examined during this study were recorded from 

the following localities: Dane Co. (2): DNR Goose Lake; 

Madison School Forest.

Hemicoelus pusillus (Fall)

(Figs. 35, 74, 133, 134; Map 15)

[Synonymy modified from Knutson 1963, White 1982] 

Hadrobregmus pusillus Fall 1905: 183.

Hemicoelus pusillus (Fall); Knutson 1963: 178.

Capsule Description (Figs. 35, 74, 133, 134)—Length: 

2.1–2.8 mm. Width: 0.9–1.2 mm. Integument Color:

orange-brown to reddish-brown; maxillary and labial palpi, 

and antennae generally lighter. Body Form: elongate, cylindrical, 2.5X longer than wide. Vestiture: pubescence 

yellowish, short, entirely recumbent. Head: antennae 

10-segmented, clubbed, last 3 antennal segments longer than 

preceding segments combined; surface densely granulate.

Pronotum: strongly crested posteriorly, sinuate laterally; 

lateral margins complete; surface densely granulate. Elytra:

parallel sided, converging apically; closely punctate-striate; 

punctures rather weakly impressed. Metathoracic Ventrite:

not excavate for reception of mesothoracic legs; with narrow longitudinal sulcus posteriorly. Legs: not received in 

ventral excavations. Abdomen: with 5 ventrites; second 

abdominal segment longer than the fifth; first ventral suture 

feebly arcuate at middle.

Diagnosis—Hemicoelus pusillus may be distinguished from 

all other members of Hemicoelus by its small size as well 

and by the second abdominal ventrite being longer than the 

fifth (Fig. 74). 

Natural History—This species is uncommonly collected 

as was noted by White (1962a). Much of its natural history, 

including larval food material, remains unknown. Wisconsin 

specimens were collected using both flight intercept and 

Lindgren funnel traps. 

Phenology—Adult specimens of H. pusillus were recorded 

in Wisconsin from mid-June to early August.

Distribution—Fall (1905) had a specimen of H. pusillus

from Dane County, Wisconsin, in his possession at the time 

of its description. In North America, this species occurs 

mainly in the northeastern United States (White 1982). 

It has been recorded as far south as Tennessee and North 

Carolina, and as far west as Wisconsin and Ontario (White 

1982). During this study, specimens were recorded from 

four Wisconsin counties.

Wisconsin Records (Map 15)—The four specimens of 

H. pusillus examined during this study were recorded from 

the following localities: Eau Claire Co. (1): Eau Claire 

County Forest; Fond du Lac Co. (1): Waupun Park Maple 

Forest SNA; Menominee Co. (1): Menominee Tribal Enterprises; Milwaukee Co. (1): Cudahy Woods SNA.

Hemicoelus umbrosus (Fall)

(Figs. 135, 136; Map 16)

[Synonymy modified from White 1965, 1982] 

Hadrobregmus umbrosus Fall 1905: 184.

Cacotemnus umbrosus (Fall); Knutson 1963: 179.

Hemicoelus umbrosus (Fall); White 1965: 113. 

Capsule Description (Figs. 135, 136)—Length: 4.3–

5.5 mm. Width: 1.4–2.0 mm. Integument Color: orangishbrown to dark reddish-brown; maxillary and labial palpi and 

antennae generally lighter. Body Form: elongate, parallel, 

2.9X longer than wide. Vestiture: pubescence yellowish, 

short, entirely recumbent. Head: antennae 11-segmented, 

clubbed, last 3 antennal segments longer than preceding 

segments combined; surface densely granulate. Pronotum:

base subequal in width to the elytra; slightly gibbous; laterally rounded; moderately convergent toward apex; lateral 

margins complete; surface densely granulate. Elytra: parallel sided, converging apically; punctures moderately impressed; strongly and rather closely punctate striate. Metathoracic Ventrite: not excavate for reception of mesothoracic legs; with a moderately impressed, longitudinal sulcus 

posteriorly; surface granulate punctate. Legs: not received 

in ventral excavations. Abdomen: with 5 ventrites.

Diagnosis—Hemicoelus umbrosus was described by Fall 

(1905) with some hesitation for a large, blackish form of 

H. carinatus, with 11-segmented antennae. In the description, Fall stated, “It is possible that in a large series the number of joints will be found to vary as in Oligomerus obtusus, 

and that umbrosus is only an extreme form of carinatus.” 

White (1962a) examined a specimen in which the antennae 

had the fourth and fifth segments nearly fused, appearing 

as an intermediate form between 10 and 11 segments. From 

this he reiterated the statement made by Fall about this species possibly being a member of the variable H. carinatus, 

but maintained it as a separate species. In his revision of 

Hadrobregmus, Knutson (1963) included specimens having 

either 10- or 11-segmented antennae as H. umbrosus. Separation of H. carinatus from H. umbrosus was said to rely on 

color as well as on the structure of the male genitalia. Hemicoelus umbrosus was said to have the posterior part of the 

median lobe spatulate as opposed to straight in H. carinatus. 
General Technical Report FPL–GTR–209

28

Wisconsin H. umbrosus are distinguished rather tentatively 

from H. carinatus based exclusively on having at least one 

11-segmented antenna. Two of the H. umbrosus specimens 

examined in fact had one 11-segmented antenna and one 

10-segmented antenna. The additional segment appears to 

arise from a constriction between the fourth and fifth segments. As in Oligomerus, it is possible that members of 

the same species demonstrate variation in the number of 

antennal segments, thereby giving further support for the 

potential synonymy of these two species. Combinations of 

10–11 and 11–12 antennal segmentation were also observed 

by Knutson (1963), although he maintained separation of 

these two species based on the shape of the distal end of 

the median lobe. Since dissection of all H. carinatus and 

H. umbrosus males was not practical, four male specimens 

were selected for comparison: one H. umbrosus specimen 

with 10–11-segmented antennae, one dark brown specimen 

of H. carinatus, and two light reddish-brown specimen of 

H. carinatus. Examination of the distal end of the median 

lobe did not appear to be significantly different among the 

selected specimens, although it is difficult to assess without 

comparing the group to specimens identified by Knutson 

himself. It is possible that all Wisconsin H. umbrosus are 

actually variations of H. carinatus, and that once a “true” 

specimen of the former is seen, differences in the median 

lobe will become apparent. Additionally, none of the Wisconsin specimens of H. carinatus or H. umbrosus collected 

could be described as “blackish” in color, although a series 

of H. carinatus did show a wide range in color from lighter 

orange-brown to dark reddish-brown. All Wisconsin specimens determined as H. umbrosus were similar in color to 

H. carinatus, supporting the idea they may be the same 

species. 

Natural History—Hemicoelus umbrosus is rather uncommon in North America as well as Wisconsin. This species 

is reported to use Abies balsamea (L.), Betula occidentalis (Hook), and Fagus sp. as larval food (Knutson 1963). 

Hemicoelus umbrosus is also known to be attracted to light 

(Knutson 1963). In Wisconsin, specimens were collected 

from Lindgren funnel and flight intercept traps; one specimen came to UV light.

Phenology—Adult specimens of H. umbrosus were recorded in Wisconsin from late May to late June.

Distribution—Scattered records of H. umbrosus have been 

found distributed throughout the United States, occurring 

from New York, New Hampshire, Michigan, and Ohio, 

south from Arkansas, and west from Nevada and California 

(White 1982). In this study, specimens were examined from 

five Wisconsin counties; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 16)—The five specimens of H. 

umbrosus examined during this study were recorded from 

the following localities: Dane Co. (1): DNR Goose Lake; 

Green Co. (1): Abraham’s Woods SNA; Jackson Co. 

(1): Black River State Forest; Lafayette Co. (1): Wedel 

Property– ~3 mi. north of Argyle; Wood Co. (1): Power’s 

Bluff SNA.

Genus Microbregma Seidlitz

[Synonymy modified from White 1982, Philips 2002] 

Type Species: Anobium emarginatum Duftschmid 1825: 

54 (by monotypy). 

Microbregma Seidlitz 1889: 501. 

Microbregmum Seidlitz; Böving 1954: 21 (lapsus calami).

Microbregma was erected by Seidlitz (1889) as a subgenus 

of Anobium for the European species Anobium emarginatum

Duftschmid, which was later found to be conspecific with 

the North American Anobium foveatum Kirby (Fall 1905). 

Fall (1905) elevated Microbregma to generic status to include Microbregma emarginatum (Duftschmid) and Microbregma emarginatum granicollis Fall.

Only a single species and two subspecies belong to this 

genus worldwide. In North America, Microbregma e. granicolle occurs in the west, and has been documented from 

Washington and California (White 1982). The distribution 

of M. e. emarginatum is noted below. 

Microbregma emarginatum emarginatum (Duftschmid)

(Figs. 32, 137, 138; Map 17)

[Synonymy modified from White 1962a, 1982] 

Anobium emarginatum Duftschmid 1825: 54.

Anobium foveatum Kirby 1837: 190.

Hadrobregmus foveatus (Kirby); LeConte 1865: 233.

Microbregma emarginatum (Duftschmid); Seidlitz 1889: 

501.

Microbregma emarginatum emarginatum (Duftschmid); 

White 1962a: 13.

Capsule Description (Figs. 32, 137, 138)—Length: 

4.0 mm. Width: 1.5 mm. Integument Color: reddishbrown to dark reddish-brown throughout; maxillary and 

labial palpi yellowish. Body Form: elongate, 2.6X longer 

than wide. Vestiture: pubescence yellowish, completely 

recumbent. Head: antennae 11-segmented, clubbed, last 

3 antennal segments longer than all preceding combined; 

surface granulate. Pronotum: lateral margins straight and 

nearly parallel, expanded laterally; disk prominently raised 

medially on either side surrounding a broad, concave depression. Elytra: striate-punctate. Metathoracic Ventrite:

not excavate for reception of mesothoracic legs. Legs: not 

received in ventral excavations. Abdomen: with 5 ventrites; 

3rd ventrite nearly 0.5X longer than ventrite 4; 5th ventrite 

with surface granulate.

Diagnosis—Microbregma emarginatum may be separated 

from all other Wisconsin Anobiinae by a combination of the 

following characters: combined length of last three antennal segments much longer than the preceding five segments 

(Fig. 32); prothoracic coxae separated by a parallel-sided 
Death-Watch and Spider Beetles of Wisconsin

29

intercoxal process; pronotal disk depressed medially 

(Figs. 137, 138); metathoracic ventrite not deeply excavate 

anteriorly; tarsal claws without a broad basal tooth; abdominal sutures distinct at center; third abdominal ventrite one 

half longer than the fourth ventrite (extracted in part from 

Philips 2002).

Morphologically, this species most closely resembles members of Hemicoelus but may be easily separated by the 

straight pronotal lateral margins, the pronotum being prominently raised on either side, surrounding a broad, concave 

depression; the third abdominal ventrite being about one 

half longer than ventrite four (Fig. 138), and the first and 

second abdominal sutures curved anteriorly.

Natural History—Specimens of M. emarginatum have been 

collected in both hardwood- and softwood-dominated forests (Jacobs et al. 2007). Lindhe et al. (2005) reported collecting numerous specimens of M. emarginatum using “netenclosure trapping” on a spruce tree stump, while Birch, 

Aspen, and Oak yielded no specimens using this method. 

Larvae purportedly feed in the outer bark of pine and hemlock as well as hickory (White 1962a, 1982). A paper by 

Jacobs et al. (2007) reported nearly 32% of M. emarginatum

were collected from girdled aspen trees. The larvae were described by Böving (1954) from specimens collected within 

bark of Picea species. 

Phenology—A single adult specimen of Microbregma

emarginatum was recorded in Wisconsin during early April.

Distribution—Microbregma emarginatum is rather sporadically distributed in North America. It has been recorded 

from British Columbia, Colorado, Minnesota, Michigan, 

New Hampshire, and Massachusetts (White 1982). During 

this study, a single specimen was recorded in Wisconsin, 

representing a NEW STATE RECORD.

Wisconsin Records (Map 17)—One Wisconsin specimen 

was examined during this study from the following location: 

Wood Co. (1): Nekoosa.

Genus Hadrobregmus Thomson

[Synonymy modified from White 1974, 1982, Philips 2002] 

Type Species: Anobium denticollis Creutzer in Panzer 1796: 

8 (by original description and monotypy). 

Hadrobregmus Thomson 1859: 89.

Coelostethus LeConte 1861: 204.

Dendrobium Mulsant and Rey 1864: 65 (as subgenus of 

Anobium).

Habrobregmus Thomson; De Leon 1952: 79 (lapsus 

calami).

Hadrobrogmus Thomson; Simeone 1962: 328 (lapsus 

calami).

Hadrobresmus Thomson; Simeone 1962: 330 (lapsus 

calami).

Hadrobegmus Thomson; Español 1970: 53 (lapsus calami).

Allobregmus Español 1970: 55 (as subgenus).

Megabregmus Español 1970: 56 (as subgenus).

Hadrobregmus was erected by Thomson (1859) for a single 

species, Anobium denticollis Creutzer. Around the same 

time, Coelostethus was proposed by LeConte (1861) for two 

species, Anobium notatum Say and Anobium quadrulum

LeConte, with the connate abdominal ventrites being the 

most notable character uniting these species (Fall 1905). 

Fall’s (1905) revision included seven species in Hadrobregmus, four of which were newly described at that time. 

In keeping with LeConte’s classification, these species all 

lacked connate abdominal ventrites. Those with this character were assigned by Fall (1905) to Coelostethus. Later, two 

other species were described in the genus: Hadrobregmus 

subconnatus Fall and Hadrobregmus destructor Fisher. 

Knutson (1963) determined the nine North American species contained within Hadrobregmus of Fall and LeConte 

did not agree in morphology with the type species, most 

notably in regard to the connate abdominal segments, and 

proposed they be split into three separate genera: Hadrobregmus, Hemicoelus, and Cacotemnus, although the latter 

of the three was soon synonymized with Hemicoelus (White 

1965). According to Knutson, Hadrobregmus should contain 

those species previously included in Coelostethus, making 

Coelostethus a junior synonym of Hadrobregmus. Desmatogaster was proposed for H. subconnatus Fall while Hemicoelus was revalidated by Knutson to include two species: 

Hemicoelus gibbicollis (LeConte) and Hemicoelus pusillus

(Fall). The remaining species under Hadrobregmus were 

placed under Cacotemnus (Knutson 1963) until White’s 

synonymy in 1965.

In North America, Hadrobregmus is composed of five species north of Mexico, with only a single species known to 

occur in Wisconsin (White 1982). Four species in this genus are known mainly from western North America, while 

Hadrobregmus notatus (Say) is found throughout eastern 

North America (White 1982). Specimens of Hadrobregmus

have been recorded from both hardwoods and softwoods 

(White 1982). In Europe, members of Hadrobregmus are 

destructive pests of old wooden structures that are infested 

by decay fungi (Viitanen 2007), although their economic 

significance within the United States appears to be far less. 

Members of this genus may be separated from all other 

Wisconsin Ptinidae by the combined length of last three antennal segments being much longer than the preceding five 

segments and the abdominal sutures distinct laterally and 

weak or absent medially. 

Hadrobregmus notatus (Say)

(Figs. 31, 79, 139, 140; Map 18)

[Synonymy modified from White 1962a, 1982] 

Anobium notatum Say 1825: 172.

Coelostethus notatus (Say); LeConte 1861: 204.

Hadrobregmus notatus (Say); Knutson 1963: 178.
General Technical Report FPL–GTR–209

30

Capsule Description (Figs. 31, 79, 139, 140)—Length: 

3.3–4.3 mm. Width: 1.4–1.9 mm. Integument Color:

reddish-brown to nearly blackish; maxillary and labial 

palpi, antennae, and legs somewhat lighter. Body Form:

moderately elongate, subcylindrical, 2.4X longer than wide.

Vestiture: pubescence dark brown to golden, patterned with 

yellowish to whitish pubescence as follows (or nearly so): 

dense at base of pronotum, sometimes extending laterally 

toward apex, present on humeri and scutellum, on elytra: 

longitudinally following suture nearly to center, medially 

with 4 short, longitudinal stripes, laterally with a spherical 

patch, lower half of elytra with distinct transverse band, 

divided at suture. Head: antennae 11-segmented, clubbed, 

combined length of last 3 antennal segments longer than all 

preceding combined; surface granulate. Pronotum: deeply 

excavate for reception of the head; base as wide as the elytra; longitudinally indented at center, with raised areas on 

either side of indentation; posterior angles deeply depressed; 

lateral margins curving upward, forming a wide U-shape; 

surface granulate. Elytra: punctate-striate; punctures deeply 

impressed, quadrate. Metathoracic Ventrite: not excavate 

for reception of mesothoracic legs; posteriorly with a rather 

deep longitudinal sulcus terminating below a deep U-shaped 

excavation anteriorly, extending into mesothoracic ventrite. 

Legs: not received in ventral excavations. Abdomen: with 

5 ventrites; sutures strongly impressed laterally, obscure to 

indistinct at center.

Diagnosis—Hadrobregmus notatus may be easily distinguished from all other Ptinidae by the variegated patterning of the dorsal pubescence (Fig. 139) and by having the 

abdominal sutures strongly impressed laterally but obscure 

to indistinct medially (Fig. 79). A few individuals examined 

during this study exhibit a reduction in the amount of patterned, dorsal pubescence. One particular specimen from 

Eau Claire Co. was almost entirely black, with the yellowish 

pubescence confined to the base of the pronotum and uppermost surface of the elytra (Fig. 140). Although this specimen is obviously aberrant from the typical H. notatus, it 

resembles this species in all other characters and is therefore 

most likely an uncommon variation of this species.

Natural History—In the United States, H. notatus does not 

appear to be of significant economic importance as there is 

little mention of it in pest control books and articles. In Wisconsin, it has not been encountered inhabiting urban structures but has been relatively abundant in forested environments. It is possible that the presence of decay fungi in the 

larval food material is required to facilitate development of 

this species, similar to what is thought to be true for members of Priobium. This then may restrict the ability of 

H. notatus to cause damage in the majority of urban 

structures. 

Larvae of H. notatus were described by Böving (1954) from 

specimens collected in “rotten oak,” “dry rotten pine,” “ash, 

chestnut and oak,” and “in pine-boards in cellar partitions.” 

The majority of Wisconsin specimens were recovered from 

Lindgren funnel traps and flight intercept traps. One specimen was taken at UV light and one in a sweep net in border 

of a hardwood forest. 

Phenology—Adult specimens of H. notatus were recorded 

in Wisconsin from early May to late September. 

Distribution—Hadrobregmus notatus is known from eastern North America, south to Mississippi and North Carolina, 

northwest into Michigan, Ohio, and Ontario, northeast into 

Massachusetts and Maine (Simeone 1960, White 1982). In 

this study, specimens were examined from 17 Wisconsin 

counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 18)—The 74 specimens of 

H. notatus examined during this study were recorded from 

the following localities: State only (1); Buffalo Co. 

(1): Engel Farm Property; Clark Co. (3): Schmidt Maple 

Woods SNA; Dane Co. (1): Swamp Lover’s Inc.; Dodge 

Co. (1): Private Property–Waterloo; Eau Claire Co.

(3): Augusta State Wildlife Area; Florence Co. (2): Morgan 

Lake; Grant Co. (4): Blue River Bluffs SNA; Wyalusing 

State Park; No other label data; Iowa Co. (1): Tower Hill 

State Park; Jackson Co. (4): Black River State Forest–

Castle Mound Pine Forest SNA; No other label data; La 

Crosse Co. (1): West Salem PC; Lincoln Co. (1): Council 

Grounds State Park–Kruger Pines SNA; Marinette Co. 

(4): Bloch Oxbow SNA; Dunbar Barrens SNA; Marquette 

Co. (1): Mecan River Public Fishing Area; Menominee Co. 

(2): Menominee Tribal Enterprises; Sauk Co. (22): Hemlock Draw TNC; Mirror Lake State Park–Echo Rock Trail; 

Shawano Co. (17): 1.3 mi. NE Wittenberg; Jung HemlockBeech Forest SNA; Trempealeau Co. (1): Perrot State 

Park; Vernon Co. (4): Mt. Pisgah Hemlock-Hardwoods 

SNA.

Genus Priobium Motschulsky

[Synonymy modified from White 1971a, 1974, 1982]

Type Species: Anobium carpini Herbst 1793: 58 

(designated by I.C.Z.N., 1976: 31).

Priobium Motschulsky 1845: 35.

Trypopitys Redtenbacher 1849: 346.

Trypopithys Redtenbacher; Baudi di Selve 1873: 

333 (lapsus calami).

Tripopitys Redtenbacher; Horn 1894: 389 (lapsus calami).

Tripopithys Pic 1931: 6 (lapsus calami).

Typopitys Redtenbacher; Brimley 1938: 196 (lapsus 

calami).

Prioblum Motschulsky; Zaitsev 1956: 72 (lapsus calami).

Priobium is a relatively small genus, represented by four 

species in North America, north of Mexico. Priobium mexicanum White, originally known only from Mexico, was first 

recorded in the United States by White in 1976 from Arizona (White 1982). The European Priobium carpini Herbst, 

was determined to be established in Maryland by Ford 

(1984); the likely source of entry was the Baltimore City 

harbor. Of the remaining two species, Priobium 
Death-Watch and Spider Beetles of Wisconsin

31

punctatum (LeConte) is known from the western United 

States, while Priobium sericeum (Say) is widely distributed, 

mainly across eastern North America (White 1982). 

Specimens of Priobium have been collected using a variety 

of techniques: rearing from infested wooden material, beating branches in wooded areas, from passive traps, and at 

UV light traps (Ford 1984). Members of this genus have 

been recorded from both hardwoods and softwoods, including oak and maple woodwork, as well as Monterey cypress, 

pine, and fir (Hatch 1961, Ford 1984). Larvae have been 

recorded from timber decayed by fungi (Böving 1954). 

Simeone (1960) in fact utilized fungi during his work on 

Ptinidae, noting other researchers (Becker 1951) had shown 

certain species, such as P. carpini, to require fungal-infested 

wood for larval development. 

Species of Priobium may be separated from all other 

Wisconsin Anobiinae by a combination of the following 

characters: antennae somewhat serrate, with the last three 

segments not much longer than the preceding five segments 

(Fig. 28); prothoracic coxae widely separated; elytral punctures quadrate, forming distinct rows; abdominal sutures 

distinct at sides, weak or indistinct medially (extracted in 

part from Philips 2002). Priobium most closely resembles 

Hadrobregmus, from which it may be immediately separated by the form of the antennae, which are clubbed and 

elongate in the latter genus. 

Priobium sericeum (Say)

(Figs. 28, 141, 142; Map 19)

[Synonymy modified from White 1962a, 1982] 

Xyletinus sericeus Say 1825: 171.

Trypopitys sericeus (Say); LeConte 1865: 234.

Priobium sericeum (Say); White 1971a: 183.

It is likely that P. sericeum was first described in Xyletinus

because of the serrate antennae (Fall 1905). Fall (1905) 

noted that the structure of the body resembled more closely 

that of Hadrobregmus except in the form of the antennae; he 

considered Priobium (as Trypopitys) to be allied with other 

Anobiini rather than Xyletinini. 

Capsule Description (Figs. 28, 141, 142)—Length: 3.3–

5.5 mm. Width: 1.3–2.3 mm. Integument Color: light 

reddish-brown to dark reddish-brown throughout; maxillary 

and labial palpi, antennae, and tarsi somewhat lighter. Body 

Form: robust, elongate, 2.4X longer than wide. Vestiture:

pubescence yellowish, short, moderately dense, recumbent 

to reclinate; arranged in rows between elytral punctures. 

Head: antennae 11-segmented, last 3 antennal segments 

nearly as long preceding 5–6 segments, segments 3–7 serrate, 8–10 elongate-triangular, 11 narrow and elongate; 

surface strongly granulate. Pronotum: concave laterally; 

longitudinally grooved at middle, groove not reaching base 

of elytra; deeply excavate ventrally, enclosing head; lateral 

margins curving; surface densely granulate. Elytra: strongly 

punctate-striate; strial punctures deep, quadrate. Metathoracic Ventrite: not excavate for reception of mesothoracic 

legs; deeply excavate anteriorly for reception of last 3 antennal segments, sometimes holding the prothoracic tarsi; 

with shallow, longitudinal sulcus posteriorly; surface of numerous, large, ring-shaped punctures, which are raised and 

more shining than the surrounding area. Legs: not received 

in ventral excavations. Abdomen: with 5 ventrites; sutures 

distinct at sides, weak toward middle; surface with numerous, large, ring-shaped punctures, which are raised and more 

shining than the surrounding area.

Diagnosis—Priobium sericeum may be separated from all 

other Wisconsin Ptinidae by a combination of the following 

characters: mandibles distant from metathoracic ventrite; 

antennae somewhat serrate, with the last three segments not 

longer than the preceding five segments (Fig. 28); pronotal 

lateral margins complete, disk deeply indented medially; 

pronotum lacking asperities; prothoracic coxae widely separated; elytral punctures square, forming distinct rows; abdominal sutures distinct at sides, weak or indistinct at center 

(similar to Fig. 79) (extracted in part from Philips 2002).

A single specimen of P. sericeum from Winnebago Co. has 

the dorsal surface pubescence atypical, somewhat approaching that of the western species, P. punctatum. Variation in 

pubescence was also seen by White (1975) in a specimen 

taken from Arizona:

A specimen of Priobium in the USNM from 5 miles west of 

Portal, Arizona is possibly distinct from punctatum (Lec.), 

sericeum (Say), and the species described below. I have 

labeled the specimen as “Priobium evidently distinct from 

sericeum & punctatum.” The abdominal sculpture is as that 

of punctatum, but the pubescence of the dorsal surface is 

about midway between the conditions in punctatum and 

sericeum, namely, the hairs are in part raised and arcuate, 

with the apices of each about parallel with the elytral surface. The pubescence of the dorsal surface of punctatum is 

clearly bristling in part; the pubescence of sericeum is almost completely appressed, with some hairs only a little 

elevated. Until a series of this form is available, its status 

remains uncertain.

Although the specimen being described by White is geographically distant from the one encountered in Wisconsin, 

the variation in the form of the pubescence is clearly analogous. For the purpose of this survey, and until additional 

specimens are found, the Wisconsin specimen is considered 

to fall within the variation of P. sericeum. 

Natural History—White (1962a, 1982) reported this species 

from dead oak branches, wild cherry, hickory, and holly, occasionally causing damage to flooring and furniture. Priobium sericeum has also been reared from dead mountain laurel 

(Kalmia latifolia) (White 1982). Larvae of P. sericeum collected from hickory and from a “fallen dead holly branch” 

were described by Böving (1954). 
General Technical Report FPL–GTR–209

32

Although P. sericeum has been infrequently encountered 

within structures (Simeone 1960), it is not generally thought 

to be of economic significance. It is possible that P. sericeum, like P. carpini, requires some degree of fungal activity within a woody substrate before it may be utilized as a 

larval food source. If this is the case, it could explain 

why this species is not seen as commonly in an indoor 

environment.

The majority of Wisconsin specimens were collected using 

Lindgren funnel and flight intercept traps. Specimens were 

also obtained at light, in Townes–Malaise traps, as well as 

on sticky traps and, incidentally, at a cantharidin bait trap. 

One specimen was collected “from milkweed.”

Phenology—Adults of P. sericeum were collected in 

Wisconsin from mid-June to late August.

Distribution—Priobium sericeum is generally known 

throughout much of eastern North America. This species 

occurs from Canada, west to Iowa and Wisconsin, southwest 

to Arizona,and southeast to Texas and Florida (Simeone 

1960, White 1982). Pellitteri and Boush (1983) reported 

this species from southern Wisconsin feed mills. During this 

study, specimens were recorded from 28 counties throughout Wisconsin.

Wisconsin Records (Map 19)—The 96 specimens of P. 

sericeum examined during this study were recorded from 

the following localities: State only (6); Adams Co. 

(6): Quincy Bluff TNC; Barron Co. (1): Kriska Residence; 

Buffalo Co. (2): Engel Farm Property; Burnett Co. 

(1): Burnett Co. Forest; Columbia Co. (5): Rocky Run 

SNA; Dane Co. (5): 7 mi. SW of UW Campus; Swamp 

Lover’s Inc.; Door Co. (3): Sturgeon Bay; Douglas Co. 

(1): Brule River State Forest; Grant Co. (1): No additional 

data; Iowa Co. (3): LWRSGA Avoca Unit; No additional locality data; Jackson Co. (2): Black River State Forest–Castle Mound Pine Forest SNA; No other label data; Jefferson 

Co. (4): Kettle Moraine Oak Opening SNA; Juneau Co. 

(2): Lemonweir Bottomland Hardwood Forest SNA; Lincoln Co. (1): Council Grounds State Park–Kruger Pines 

SNA; Marinette Co. (14): Dunbar Barrens SNA; Marquette Co. (2): Fox River Wildlife Refuge; Menominee

Co. (4): Menominee Tribal Enterprises; Private Property–

Legend Lake–Spirit Island Road; Milwaukee Co. (3): No 

additional data; Racine Co. (2): Renak–Polak Maple–Beech 

Woods SNA; Richland Co. (1): LWRSWA Lone Rock 

Unit; Rusk Co. (1): Bruce; Sauk Co. (8): Hemlock Draw 

TNC; Shawano Co. (4): 1.3 mi. NE Wittenberg; Jung 

Hemlock-Beech Forest SNA; Sheboygan Co. (1): Kettle 

Moraine Red Oaks SNA; Vernon Co. (1): Mt. Pisgah Hemlock–Hardwoods SNA; Waupaca Co. (2): Hartman Creek; 

Mud Lake Bog SNA; Winnebago Co. (1): Menasha to B/L 

N. Shore Golf Course; Wood Co. (9): Griffith St. Nursery; 

Grand Rapids; Nekoosa Plant.

Genus Trichodesma LeConte

[Synonymy modified from White 1982, Philips 2002] 

Type Species: Anobium gibbosum Say 1825: 

171 (by original description). 

Trichodesma LeConte 1861: 204.

Ptinodes LeConte 1861: 204.

Microtrichodesma Pic 1931: 2.

Trichedesma LeConte; Borror and DeLong 1954: 

305 (lapsus calami).

LeConte (1861) described two genera, Ptinodes and Trichodesma, that were separated based on the structure of the 

mesosternum. Fall (1905) stated that “the two genera are 

separated on rather trifling differences and may yet have to 

be united,” but retained them as separate genera based on 

the structure of the “palpi,” antennae, legs, and abdomen 

(White 1974). White (1974) reevaluated the differences seen 

by Fall (1905) and concluded Ptinodes is synonymous with 

Trichodesma.

Ten species of Trichodesma are known from North America, 

north of Mexico, with species diversity greatest in the southwestern United States (White 1982). Various hardwood trees 

have been reported as hosts for many members of this genus 

(Philips 2002). In Wisconsin this genus is represented by a 

single species, Trichodesma gibbosa (Say).

Males and females of Trichodesma are not readily separated; 

however, as with most Ptinidae, the eyes of the male tend to 

be slightly larger and the last three antennal segments more 

elongate than in the female (Fall 1905).

Trichodesma gibbosa (Say)

(Figs. 30, 68, 143, 144; Map 20)

[Synonymy modified from White 1962a] 

Anobium gibbosum Say 1825: 171.

Trichodesma gibbosa (Say); LeConte 1861: 204.

Capsule Description (Figs. 30, 68, 143, 144)—Length: 

6.4–7.0 mm. Width: 3.0–3.3 mm. Integument Color: dark 

reddish-brown throughout. Body Form: cylindrical, robust, 

2.1X longer than wide. Vestiture: of both recumbent and 

erect pubescence, obscuring surface sculpture in part; short, 

recumbent pubescence grayish-white to white, dense on 

lateral and apical pronotal surface, absent medially at base, 

forming a broad band on apical half of elytra, also present 

on humeral region and scutellum; basal area of elytra less 

pubescent; head, legs, and ventral surface densely clothed in 

short, grayish-white to white recumbent pubescence; erect 

white pubescence widely distributed on dorsal and ventral 

surface, head, and legs; pronotum with tufts of dark brown 

and golden brown setae medially on raised part of pronotal 

disk, also present on humeri and in patches above and below 

white pubescent band on elytra. Head: antennae 11-segmented; combined length of last 3 antennal segments slightly longer than all preceding combined; surface completely 
Death-Watch and Spider Beetles of Wisconsin

33

concealed by pubescence. Pronotum: strongly raised at 

center of disk; narrowed and slightly expanded laterally; 

appearing divided medially; surface strongly, densely granulate. Elytra: with punctures arranged in rows, obscured by 

pubescence in part; surface strongly granulate. Metathoracic Ventrite: not excavate for reception of mesothoracic 

legs; posteriorly with a somewhat deep, narrow, longitudinal 

sulcus; surface strongly granulate. Legs: not received in 

ventral excavations; tarsal claws with a broad, basal tooth. 

Abdomen: with 5 ventrites.

Diagnosis—Trichodesma gibbosa may be easily separated 

from all other Wisconsin Ptinidae by the dense elytral pubescence, which forms a white band across the apical half of 

the elytra (Fig. 143), and the tarsal claws, which possess a 

broad, basal tooth (Fig. 68). 

Natural History—Böving (1954) described the larvae of 

this species from specimens collected in the “dead trunk of 

Persea.” This description includes larvae of the morphologically similar Trichodesma klagesi Fall, collected in Benzoin 

sp. (Fever bush), which he stated are indiscernible from 

T. gibbosa. Specimens of T. gibbosa have also been recorded from hickory, elm sprouts, sour gum, tupelo (Nyssa 

sylvatica), and sweetgum joists and studding (Fall 1905, 

White 1982).

A single Wisconsin specimen was collected in a flight intercept trap baited with cantharidin, while a second specimen 

was found crawling on the outside of a cantharidin bait trap. 

Although both specimens were collected using cantharidin, 

there is no evidence to indicate that this chemical is an attractant for T. gibbosa as many other locations and traps 

using this compound did not yield specimens.

Phenology—Adult specimens of T. gibbosa were recorded 

in Wisconsin from mid- to late June. 

Distribution—Trichodesma gibbosa occurs throughout 

much of the eastern and central United States (White 1982). 

This species has been found as far west as Kansas, Louisiana, and Iowa, south to Florida, and north into Michigan, 

New York, and Ontario (White 1982). In this study, specimens were examined from two southeastern Wisconsin 

counties; they constitute a NEW STATE RECORD and 

new northwestern range extension of the known distribution 

for the species.

Wisconsin Records (Map 20)—The two specimens of 

T. gibbosa examined during this study were recorded from 

the following localities: Milwaukee Co. (1): Cudahy Woods 

SNA; Racine Co. (1): Renak–Polak Maple–Beech Woods 

SNA.

Genus Oligomerus Redtenbacher

[Synonymy modified from White 1974, 1982]

Type Species: Anobium brunneus Olivier 1790: 8 (by 

monotypy).

Oligomerus Redtenbacher 1849: 347.

Oligomerinus Portevin 1931: 484.

Oligomerus was erected by Redtenbacher (1849). The number of species described in Oligomerus for North America 

has grown since its inception partially as a result of the revisionary work done by Fall (1905) and White (1976b). Fall 

(1905) described three species: Oligomerus californicus and 

Oligomerus tenellus, each from single specimens collected 

from California and Arizona, respectively; Oligomerus

brevipilis was described from females ranging from the 

east coast into Michigan and was recorded from Wisconsin 

(White 1976b). While revising the North American species 

of Oligomerus, White (1976b) described six new species 

and confirmed strong generic similarities among them after 

examination of the male genitalia of all species, with the 

exception of Oligomerus delicatulus (Fall), O. californicus, 

and O. brevipilis.

Fourteen species of Oligomerus occur in North America, 

four of which are found in Wisconsin. Specimens of Oligomerus tend to be rather rarely collected in Wisconsin as well 

as across the country. Fall (1905) noted that few collections 

in North America contain more than a half a dozen 

specimens. 

Members of Oligomerus can be distinguished from all other 

Anobiinae by the close approximation of the prothoracic 

coxae (except Oligomerus sericans (Melsheimer)), the more 

rounded pronotum, and the elytral striae being comprised 

of shallow punctures (extracted in part from Philips 2002). 

Species of Oligomerus most closely resemble those of 

Hemicoelus but can be immediately distinguished by their 

contiguous prothoracic coxae or by their shallow elytral 

punctures. 

Species identifications in the genus can be difficult in part 

because of the variation in number of antennal segments 

observed within a single species. Fall (1905) documented 

a series of Oligomerus obtusus LeConte in which 10 specimens had 11-segmented antennae, 12 had 10-segmented 

antennae, and one had one of each. It was noted that this 

discrepancy could partially have resulted from a constriction 

on one of the antennal segments, which may appear as a division depending on the depth of the impression (Fall 1905). 

Although Fall (1905) thought this variation in number of antennal segments was not seen in species with nine-segmented antennae, nor in O. sericans, a specimen of O. sericans

was collected in Wisconsin with one 9-segmented and one 

10-segmented antenna. Therefore, the number of antennal 

segments cannot be used critically in making species level 

determinations despite the fact that White’s (1962a) and 

Fall’s (1905) keys both include this character. 

Males and females may be easily separated based on antennal structure. The antennal club of males is nearly 1.5X the 

length of the club exhibited by females. Eyes of males also 

tend to be relatively larger and closer in proximity.
General Technical Report FPL–GTR–209

34

Key to the Wisconsin Species of Adult Oligomerus

[Modified from Fall 1905 and White 1976b]

1 Prothoracic coxae separated by about 0.5 transverse coxal diameter by a broadly 

 triangular intercoxal process; pubescence of head and pronotum distinctly erect 

 (Fig. 85); male genitalia (Fig. 95)......................................................................................sericans (Melsheimer) (p. 36)

1’ Prothoracic coxae contiguous to separated by not >0.33X transverse coxal diameter 

 by a triangular intercoxal process which becomes laminate posteriorly; pubescence of 

 head and pronotum recumbent to moderately erect.........................................................................................................2

2 (1’) Pubescence of head and pronotum moderately erect (Fig. 148); male genitalia (Fig. 96) ....... brevipilis Fall (p. 34)

2’ Pubescence of head recumbent to slightly erect, that of pronotum entirely recumbent ..................................................3

3 (2’) Sides of pronotum evenly rounded throughout (Figs. 149, 150); anterior metasternal 

 process forming an obtuse angle; pubescence of head slightly or not erect; male genitalia 

 (Fig. 97)................................................................................................................................obtusus LeConte (p. 35)

3’ Pronotum prominent, flared at base, appearing pinched medially (Fig. 145); anterior 

 metasternal process forming an acute to right angle; pubescence of head completely 

 recumbent; male genitalia (Fig. 98)........................................................................................alternans LeConte (p. 34)

Oligomerus alternans LeConte

(Figs. 98, 145, 146; Map 21)

Oligomerus alternans LeConte 1865: 228.

Capsule Description (Figs. 98, 145, 146)—Length: 

4.0–4.6 mm. Width: 1.5–1.7 mm. Integument Color: Dark 

reddish-brown to black; maxillary and labial palpi, antennae, and tarsi reddish-yellow to yellowish. Body Form:

elongate, cylindrical, 2.7X longer than wide. Vestiture:

pubescence yellowish, entirely recumbent. Head: antennae 

9-segmented, clubbed, combined length of last 3 antennal 

segments much longer than preceding segments combined; 

surface finely, thickly granulate. Pronotum: disk strongly 

elevated and compressed medially; surface finely, moderately granulate. Elytra: punctate-striate; elytral intervals 

convex; strial punctures without distinct margins. Metathoracic Ventrite: not excavate for reception of mesothoracic 

legs; anterior metasternal intercoxal process forming a more 

or less acute angle; posteriorly with a shallow, longitudinal 

sulcus, devoid of setae. Legs: not received in ventral excavations; prothoracic coxae contiguous. Abdomen: with 

5 ventrites. Genitalia: dorsum of basal piece with inner 

margins of distal lobes narrowly parallel along middle third, 

slightly expanded, vasiform basally.

Diagnosis—Oligomerus alternans may be confused with 

darker specimens of O. obtusus if the configuration of the 

metasternal intercoxal process is misinterpreted. In O. alternans the process extending between the mesothoracic coxae 

is acute (<90° angle). In O. obtusus the angle is obtuse to 

arcuate. However, in some specimens of O. obtusus, the 

anterior portion of the process is raised and extended 

further between the mesothoracic coxae, giving the false 

impression that the angle is acute. To prevent misinterpretation, the angle should be evaluated before the raised portion 

of the process begins. Dissection of the male genitalia will 

easily separate this species from O. obtusus (Fig. 98).

Natural History—Little is known about the natural history 

of this species, as it is uncommonly encountered. In Wisconsin, one specimen was collected at UV light, one from a 

Lindgren funnel trap, and a third specimen lacked any 

natural history data. 

Phenology—Adult specimens of O. alternans were 

recorded in Wisconsin from late June to mid-July.

Distribution—Oligomerus alternans is generally distributed 

throughout the eastern United States, extending west to 

Kansas and south to Mississippi (White 1982). This species is also recorded as far north as Canada (Fall 1905). In 

this study, specimens were examined from three Wisconsin 

counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 21)—The three specimens of 

O. alternans examined during this study were recorded from 

the following localities: Dane Co. (1): No other label data; 

Richland Co. (1): No other locality data; Sauk Co. 

(1): Hemlock Draw TNC.

Oligomerus brevipilis Fall

(Figs. 96, 147, 148; Map 22)

Oligomerus brevipilis Fall 1905: 166.

Oligomerus brevipilis was described by Fall (1905) 

from only female specimens.

Capsule Description (Figs. 96, 147, 148)—Length: 4.8–

6.6 mm. Width: 1.8–2.4 mm. Integument Color: dark 
Death-Watch and Spider Beetles of Wisconsin

35

reddish-brown to nearly black; maxillary and labial palpi, 

antennae, and legs reddish-yellow to reddish-brown. Body 

Form: elongate, cylindrical, 2.7X longer than wide. Vestiture: pubescence yellowish, head and usually pronotum 

with intermixed, erect setae among recumbent setae; erect 

setae sparser on elytra. Head: antennae 9-segmented, 

clubbed, combined length of last 3 antennal segments much 

longer than preceding segments combined; surface granulate. Pronotum: convex, stout; surface densely, minutely 

granulate, feebly shining. Elytra: punctate-striate; strial 

punctures without distinct margins; feebly impressed. Metathoracic Ventrite: not excavate for reception of mesothoracic legs; posteriorly with a shallow, narrow and distinctly 

shining longitudinal sulcus, mostly devoid of pubescence. 

Legs: not received in ventral excavations; prothoracic coxae 

contiguous. Abdomen: with 5 ventrites. Genitalia: dorsum 

of basal piece with inner margins of distal lobes widely 

subparallel through much of their length, slightly rounded 

basally.

Diagnosis—Oligomerus brevipilis may be separated from 

all other Wisconsin Oligomerus, including Oligomerus alternans LeConte, to which it is most closely related, by the 

contiguous prothoracic coxae, the erect pubescence of the 

head and pronotum (Fig. 148), and the structure of the 

male genitalia (Fig. 96). These characters, in addition to 

the elytral strial punctures lacking distinct margins 

(e.g., Fig. 77), will help distinguish this species from other 

Anobiinae. 

Although a subset of O. brevipilis specimens examined during this study exhibit less distinctly erect pronotal pubescence, the erect cranial pubescence distinguishes them from 

O. alternans, with which they may be confused. The structure of the male genitalia of these specimens did seem to 

reveal an intermediate form between O. brevipilis and that 

of O. alternans, although with so few specimens (n = 19), it 

is not prudent to make any generalizations. The validity of 

both species is likely sound based on the condition of 

the pubescence in most specimens, but this small subset 

of O. brevipilis might provide good candidates for future 

genetic studies. 

Variation in the number of antennal segments in this species 

was not observed as was previously seen in O. sericans and 

O. obtusus. However, this could be due to the small number 

of specimens collected from the state.

Natural History—Little is known about the natural history 

of this species as it tends to be rather uncommonly collected. In Wisconsin, UV light sampling provided the majority 

of specimens (42%), of which 88% were female. Specimens 

were also obtained using Lindgren funnel traps, flight intercept traps, and a Townes–Malaise trap. Three specimens 

were collected from underneath driftwood debris on a Lake 

Michigan beach in Sheboygan County. The majority of 

specimens were collected in areas dominated by hardwoods 

with a few specimens from hardwood cut sites.

Phenology—Adult specimens of O. brevipilis were recorded 

in Wisconsin from mid-June to late July.

Distribution—Oligomerus brevipilis is known throughout 

much of the northeastern United States (White 1982). It has 

been collected as far south as West Virginia and Washington 

D.C., and as far west as Wisconsin and Michigan (White 

1976b, 1982). During this study, specimens were recorded 

from 10 Wisconsin counties. 

Wisconsin Records (Map 22)—The 19 specimens of 

O. brevipilis examined during this study were recorded 

from the following localities: Dane Co. (5): DNR Goose 

Lake; Private Property–Cottage Grove; Private Property–

Deerfield; No other locality data; Dodge Co. (3): Private 

Property–Waterloo; Jefferson Co. (1): No other label data; 

Marquette Co. (1): Fox River Wildlife Refuge; Milwaukee 

Co. (1): Sheridan Park; Richland Co. (1): No other locality 

data; Rock Co. (1): Private Property–1.7mi NW Janesville; 

Sheboygan Co. (3): Kohler–Andrae State Park; Waupaca 

Co. (2): Mud Lake Bog SNA; Wood Co. (1): Powers Bluff 

SNA.

Oligomerus obtusus LeConte

(Figs. 97, 149, 150; Map 23)

Oligomerus obtusus LeConte 1865: 228.

Capsule Description (Figs. 97, 149, 150)—Length: 4.6–

5.2 mm. Width: 1.7–1.8 mm. Integument Color: dark 

reddish-brown to light reddish-brown. Body Form: elongate, cylindrical, 2.9X longer than wide. Vestiture: pubescence yellowish, entirely recumbent to slightly erect on 

head, especially just above mandibles. Head: antennae 9-, 

10- or 11-segmented, clubbed, combined length of last 

3 antennal segments much longer than preceding segments 

combined; surface granulate. Pronotum: moderately gibbous; surface granulate. Elytra: punctate-striate; strial punctures without distinct margins. Metathoracic Ventrite: not 

excavate for reception of mesothoracic legs; posteriorly with 

a distinctly shining, shallow and narrow longitudinal sulcus. 

Legs: not received in ventral excavations; prothoracic coxae 

contiguous. Abdomen: with 5 ventrites. Genitalia: dorsum 

of basal piece with inner margins of distal lobes widely subparallel along middle third, converging basally, acuminate.

Diagnosis—Separation of darker specimens of O. obtusus

from O. alternans, with which it may be mistaken, is discussed in detail under the diagnosis for O. alternans. Oligomerus obtusus may also be confused with specimens of the 

genus Hemicoelus, especially those of Hemicoelus carinatus 

(Say), but are readily separated by the close approximation 

of the prothoracic coxae, the elytral strial punctures with 

less distinct margins (Figs. 76, 77), and the more cylindrical 

body form.

Natural History—Although Fall (1905) and White (1962a) 

stated this species is the most frequently collected member 
General Technical Report FPL–GTR–209

36

of Oligomerus, only 11 specimens were collected from Wisconsin. Champlain and Knull (1922) reported O. obtusus

reared from Fagus americana. Wisconsin specimens were 

collected using Lindgren funnel, Townes–Malaise and flight 

intercept traps, as well as a single specimen taken at a mercury vapor lamp. One specimen was collected “crawling on 

wet sand near the water’s edge” of a Lake Michigan beach 

in the early afternoon. All specimens were collected in areas 

dominated by hardwoods; two were obtained at hardwood 

cut sites.

Phenology—Adult specimens of O. obtusus were recorded 

in Wisconsin from late June to early August.

Distribution—Oligomerus obtusus is known only from 

northeastern North America, extending northward into Canada (White 1982). Ohio and Washington D.C., represent the 

southern-most boundary of this species (White 1982), with 

Wisconsin likely representing the western-most boundary of 

its distributional range. In this study, specimens were examined from eight Wisconsin counties; they constitute a NEW 

STATE RECORD and new northwestern range extension 

of the known distribution for the species.

Wisconsin Records (Map 23)—The 11 specimens of 

O. obtusus examined during this study were recorded from 

the following localities: Door Co. (1): Sturgeon Bay; Florence Co. (1): Private Property; Forest Co. (1): Nicolet National Forest; Racine Co. (1): Renak–Polak Maple–Beech 

Woods SNA; Sheboygan Co. (2): Kettle Moraine Red Oaks 

SNA; Kohler–Andrae State Park; Trempealeau Co. 

(1): Perrot State Park; Waupaca Co. (2): Mud Lake Bog 

SNA; Wood Co. (2): Powers Bluff SNA.

Oligomerus sericans (Melsheimer)

(Figs. 27, 85, 93–95, 151, 152; Map 24)

[Synonymy modified from White 1962a, 1982]

Anobium sericans Melsheimer 1846: 309.

Oligomerus thoracicus LeConte 1861: 205.

Oligomerus sericans (Melsheimer); LeConte 1865: 228.

Capsule Description (Figs. 27, 85, 93–95, 151, 152)—

Length: 3.3–5.1 mm. Width: 1.4–1.9 mm. Integument 

Color: brownish-black to black; maxillary and labial palpi, 

antennae and legs yellowish-red to yellowish-brown. Body 

Form: elongate, cylindrical, 2.6X longer than wide. Vestiture: pubescence yellowish, recumbent, with intermixed 

erect setae, which are numerous on head and pronotum, infrequent on elytra. Head: antennae generally 10-segmented, 

clubbed, combined length of last 3 antennal segments 

much longer than preceding segments combined; surface 

somewhat shining, finely granulate. Pronotum: convex, 

stout; surface somewhat shining with small scattered granules. Elytra: slightly rough, punctate-striate; inner rows of 

punctures irregular and feebly impressed. Metathoracic 

Ventrite: not excavate for reception of mesothoracic legs; 

posteriorly with a shallow, narrow and distinctly shining 

longitudinal sulcus (sulcus infrequently indiscernible). 

Legs: not received in ventral excavations; prothoracic coxae 

separated about 0.5 transverse coxal diameter by a broadly 

triangular intercoxal process. Abdomen: dorsum of basal 

piece with inner margins of distal lobes narrowly subparallel 

along middle third, distinctly rounded basally.

Diagnosis—Oligomerus sericans is clearly aberrant with 

respect to all other Wisconsin Oligomerus species. The erect 

pubescence of the head and pronotum (Fig. 85), separation 

of the prothoracic coxae by a broadly triangular intercoxal 

process, as well as the structure of the male genitalia 

(Fig. 95) easily distinguish this species from most other 

Anobiinae. 

As noted in the generic introduction, Oligomerus exhibits 

variation in the number of antennal segments even within 

a single specimen (Fall 1905). Cursory light microscopy 

examination of O. sericans from Wisconsin showed that 

whereas most specimens had 10-segmented antennae, a 

single individual was found to have antennae with 10 (left) 

and nine (right) antennal segments. To examine this more 

closely, the antennae of this individual were removed and 

examined using compound light as well as a scanning election microscopy (SEM). The fifth and sixth antennal segments of the left antenna are very nearly equal in size and 

appear nearly fused, but are distinctly separated (Fig. 93). 

The right antenna however showed no such division and is 

clearly nine-segmented (Fig. 94). Therefore, it may be concluded that the variation observed in the number of antennal 

segments among specimens as well as within individuals 

may itself constitute a generic character, as was suggested 

by Fall (1905).

Natural History—The natural history of O. sericans is not 

well known. Larvae of this species were described in detail 

by Böving (1954) from specimens reported from chestnut as 

well as from the end of an English walnut twig. Fall (1905) 

listed two specimens from the LeConte collection labeled as 

being from Carya (hickory) and white oak. The majority of 

Wisconsin specimens were collected using Lindgren funnel 

traps and flight intercept traps. Three specimens came from 

cantharidin-baited traps, although the association is likely 

incidental. Although the majority of specimens came from 

areas dominated by hardwoods, some specimens were from 

areas dominated by Pinus spp.

Phenology—Specimens of O. sericans were recorded in 

Wisconsin from mid-June to mid-August. A single specimen 

[IRCW] was collected on 17 November 1969 from a “roadside” in Dane County. 

Distribution—Oligomerus sericans is widespread throughout much of the eastern United States and appears to be the 

most commonly collected species of Oligomerus in Wisconsin. According to White (1982), this species occurs as 

far west as Minnesota and as far south as Kentucky. Fall’s 

(1905) revision included specimens from Canada. In this 
Death-Watch and Spider Beetles of Wisconsin

37

study, specimens were examined from 14 Wisconsin counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 24)—The 45 specimens of 

O. sericans examined during this study were recorded from 

the following localities: State only (1); Adams Co. 

(4): Quincy Bluff TNC; Barron Co. (1): Kriska Residence; 

Columbia Co. (5): Rocky Run SNA; Dane Co. (7): Madison; Swamp Lover’s Inc.; No other label data; Eau Claire 

Co. (1): UW Eau Claire Campus; Grant Co. (3): Wyalusing 

State Park; Iowa Co. (2): Ridgeway Pine Relict SNA; No 

other locality data; Lafayette Co. (3): Wedel Property– 

~3 mi. north of Argyle; Marquette Co. (3): Fox River 

Wildlife Refuge; Milwaukee Co. (2): No other label data; 

Racine Co. (1): Renak–Polak Maple–Beech Woods SNA; 

Richland Co. (1): LWRSWA Lone Rock Unit; Sauk Co. 

(8): Hemlock Draw TNC; Sheboygan Co. (3): Kettle Moraine Red Oaks SNA.

Genus Stegobium Motschulsky

[Synonymy modified from White 1974, 1982] 

Type Species: Dermestes paniceus Linnaeus 1758: 

357 (by monotypy). 

Stegobium Motschulsky 1860: 154.

Sitodrepa Thomson 1863: 166.

Artobium Mulsant and Rey 1864: 67.

Autobium Mulsant and Rey; Reitter 1901: 

23 (lapsus calami).

Litropeda Thomson; Stebbing 1914: 179 (lapsus calami).

Sidrotepa Thomson; Bosq 1934: 324 (lapsus calami).

Sitoprepa Thomson; Seabra 1939: 284 (lapsus calami).

Stegobium was erected by Motschulsky for Dermestes paniceus Linnaeus (White 1974). The generic name Sitodrepa, 

which is commonly used in earlier documents (notably Fall 

1905 and Pic 1912a), was described by Thomson for the 

same species, D. paniceus, now considered an invalid synonym of Stegobium (White 1982). This genus consists of a 

single, nearly cosmopolitan species (White 1974). 

Stegobium paniceum (Linnaeus)

(Figs. 29, 66, 67, 153, 154; Map 25)

[Synonymy modified from White 1962, 1982] 

Dermestes paniceus Linnaeus 1758: 357.

Anobium ferrugineum Herbst 1783: 27.

Ptinus testaceum Thunberg 1784: 6.

Ptinus upsaliense Gmelin 1790: 1608.

Anobium minutum Fabricius 1792: 238.

Ptinus tenuicorne Marsham 1802: 84.

Ptinus rubellum Marsham 1802: 85.

Anobium pusillum Gyllenhal 1808: 294.

Anobium tenuistriatum Say 1825: 172.

Anobium ireos Villa and Villa 1833: 33.

Anobium obesum Melsheimer 1846: 309.

Anobium nanum Kuester 1849: 45.

Anobium panum Mulsant and Rey 1864: 114.

Sitodrepa panicea (Linnaeus); LeConte 1865: 229.

Stegobium paniceum (Linnaeus); Jacobson 1912: 358.

The worldwide distribution and economic significance of 

this species has led to its re-description numerous times 

throughout history.

Capsule Description (Figs. 29, 66, 67, 153, 154)—Length: 

1.9–3.1 mm. Width: 0.9–1.4 mm. Integument Color:

yellowish-brown to reddish-brown; maxillary and labial 

palpi, antennae, and tarsi somewhat lighter, usually reddishyellow to yellow. Body Form: moderately robust, 2.3X 

longer than wide. Vestiture: pubescence yellowish, mostly 

recumbent, bristling in part, dense, especially on head and 

dorsal surface. Head: antennae 11-segmented, clubbed, 

combined length of last 3 antennal segments much longer 

than preceding segments combined; surface finely granulate. 

Pronotum: not strongly convex, rather flat medially; lateral 

margin somewhat serrate; surface finely granulate. Elytra:

punctate-striate, punctures obscure, elongate, longitudinally 

closed spaces. Metathoracic Ventrite: not excavate for 

reception of mesothoracic legs; with a narrow longitudinal 

sulcus on posterior half. Legs: not received in ventral excavations; prothoracic coxae separated by a V-shaped process; 

tibial spurs small and difficult to see. Abdomen: with 

5 ventrites.

Diagnosis—Stegobium paniceum is readily distinguished 

from all other Wisconsin Anobiinae by a combination of the 

following characters: length of the last three antennal segments much longer than all preceding segments (Fig. 29); 

prothoracic coxae separated by a V-shaped to slightly truncate intercoxal process; elytral punctures obscure, elongate, 

longitudinally closed spaces (extracted in part from Philips 

2002). In most specimens, the prothoracic coxal process 

is obviously V-shaped, although there are some examples 

where the tip of the process is slightly truncate, which may 

cause some confusion in the key to genera when one is not 

entirely familiar with the species. Males and females of 

S. paniceum may be separated by the shape of the tarsal 

claw (Halstead 1986) (Figs. 66, 67).

Natural History—Stegobium paniceum, named in reference to this beetle’s habit of feeding on bread products 

(Hedges and Lacey 1996), is more commonly known as the 

drugstore beetle. As well-preserved breads were frequently 

presented as funeral offerings in ancient Egypt, infestations 

of S. paniceum tended to be rather common occurrences 

within ancient Egyptian tombs, including the antechamber 

of king Tut-ankh-amun (1333–1323 B.C.) (Levinson and 

Levinson 1994). This species is a serious economic pest of 

a variety of stored products (White 1982). As the common 

name suggests, S. paniceum has been found to infest almost 

any stored material, which includes prescription drugs, 

strychnine powder, and tin cans (Cabrera 2001, VanRyckeghem 2004). They are also known to chew through most 

food packaging, including aluminum foil and lead sheets 

(Hedges and Lacey 1996). Food products such as flour, dry 
General Technical Report FPL–GTR–209

38

mixes, spices, chocolate, dried herbs, cookies, grains, seeds, 

cereal, dried fruits, and vegetables are also infested in addition to such non-food items as wool, leather, horns, hides, 

books, manuscripts, wood, and museum specimens (Smith 

and Whitman 1992, VanRyckeghem 2004). One technical 

bulletin relayed an anonymous quote that this species “eats 

anything but cast iron” (Cabrera 2001). Rees (2004) stated 

that outside of an urban environment, “S. paniceum has been 

found living in bee hives, feeding on pollen collected by 

bees.” Woodroffe (1953) reported this species from nests 

of pigeons.

The ability of S. paniceum to develop on such a wide variety 

of food materials has been a topic of study for many years. 

Karawaiew (1899) first described the presence of a structure 

called a mycetom, located in the intestine, which was later 

found to contain intracellular, yeast-like symbionts that 

provide a source of nutrients for the host (Pant and Fraenkel 1954). These symbionts are able to produce vitamins 

of the B-complex, in addition to being a source of sterols 

that the insect needs for development (Pant and Fraenkel 

1954). This type of symbiotic relationship is also seen in the 

ptinid Lasioderma serricorne Fabricius, which is known to 

develop on toxic tobacco leaves (Pant and Fraenkel 1954). 

This adaptation has no doubt given this species significant 

advantage throughout its evolutionary history.

The complete lifecycle of S. paniceum is thought to last 

approximately seven months (Smith and Whitman 1992). 

The adult female lays eggs in and around the food material, which hatch after only a few days. The larvae then go 

through four to six instars during a period of four to five 

months. Mature larvae pupate in a silken cocoon composed 

partially of food material, emerging after only 12–18 days 

(Smith and Whitman 1992). However, the duration of larval 

development depends strongly on the nutritional content of 

the food, as well as on temperature and humidity (Hedges 

and Lacey 1996, Rees 2004). Rees (2004) stated the optimal 

conditions for development of S. paniceum to be around 

30 °C (85 °F) and 60–90% relative humidity for 40 days. 

Infestations of S. paniceum are often controlled in an inhome environment by finding the source of the infestation 

and removing the affected material. Infestations within 

warehouses can be slightly more problematic. Kuwahara 

et al. (1975, 1978) examined the response of males to the 

female sex pheromone, 2,3-dihydro-2,3,5-trimethyl-6-

(1-methyl-2-oxobutyl)-4H-pyran-4-one (known commonly 

as stegobinone). Their work suggested that this pheromone 

may be used as a monitoring tool to determine the extent of 

S. paniceum populations within warehouses where infestations may occur. Light traps have also been used alone or in 

conjunction with pheromones to monitor insect populations 

(VanRyckeghem 2004). Historically, fumigation has been 

effective in controlling S. paniceum infestations using 

aluminum phosphide, magnesium, phosphine, methyl 

bromide, or sulfuryl fluoride as fumigants (Gilberg 1989, 

VanRyckeghem 2004), although the latter is not suitable 

for fumigation of food products (Hedges and Lacey 1996). 

However, increasing environmental awareness has substantially reduced the use of many of these fumigants, particularly methyl bromide, as treatment options, prompting 

examination of the effects of carbon dioxide and other inert, 

low-oxygen gases as potential alternatives (Gilberg 1989, 

Gunasekaran and Rajendran 2005). The use of extreme temperatures is also sometimes used to treat severe infestations 

(VanRyckeghem 2004).

All Wisconsin specimens were collected from within homes 

or buildings. One particular infestation at a Manitowoc 

County home involved a kitchen and bathroom that were 

re-infested from the previous year. This was likely the result 

of improper removal of infested materials. The homeowner 

maintained that the drugstore beetles were biting their family cat, so it is possible that pet food was the source of the 

infestation, as is commonly observed, although there is no 

evidence to suggest that S. paniceum acts in this manner 

toward household pets.

A second infestation occurred at a food processing plant 

located in Owen, Wisconsin. Within the large plant, 

S. paniceum was found only in the area that processed imitation cheese by dumping bags of dry product into large 

vats. Since the air ducts are cleaned only every few years, a 

large build-up of dry product accumulated within the duct 

work. Samples showed countless specimens of S. paniceum

developing on this material. In addition to the beetles, wingless parasitic bethylid wasps were also found on the walls 

near the infested product, presumably developing within the 

drugstore beetle larvae. The company resolved to routinely 

clean out the air ducts.

A number of other indoor infestations in Wisconsin originated from dog food or dog biscuits. Other infested food 

materials reported include a box of dry vermicelli, flourbased food products, as well as numerous specimens said to 

be from “furniture.” One infestation occurred in the basement of a six-month old home wherein the previous owner 

brewed beer. 

Phenology—Adult specimens of S. paniceum have been 

recorded throughout the year from within various structures 

in Wisconsin. 

Distribution—Stegobium paniceum is widely distributed 

across North America as well as worldwide (White 1982), 

mostly through commerce (White 1962a). Pellitteri (1977) 

and Pellitteri and Boush (1983) reported this species from 

feed mills surveyed in southern Wisconsin. During this 

study, specimens were recorded from seven Wisconsin 

counties.

Wisconsin Records (Map 25)—The 189 specimens of 

S. paniceum examined during this study were recorded 

from the following localities: State only (1); Dane Co. 

(94): Eagle Heights, Madison; Madison; No other label 
Death-Watch and Spider Beetles of Wisconsin

39

data; Verona; Jefferson Co. (5): No other locality data; 

Manitowoc Co. (15): Manitowoc/ Sent to Manitowoc 

County Health Department; Milwaukee Co. (3): Milwaukee; Vernon Co. (2): Hillsboro; Waukesha Co. 

(66): Oconomowoc; No other locality data; Waukesha; 

Winnebago Co. (3): Oshkosh.

Subfamily Ptilininae

Ptilininae was established by Shuckard (1840) to include six 

species contained within four genera: Lasioderma Stephens, 

Ochina Ziegler, Xiletinus Latreille (emended to Xyletinus), 

and Ptilinus Mueller. Classifications by LeConte (1861) and 

Fall (1905) considered Ptilininae (as Ptilinini) as monogeneric in North America, containing only the genus Ptilinus. Pic 

(1912a) also listed only Ptilinus for North American Ptilininae in addition to Plumaria Reitter and Ptilineurus Reitter, 

both said to occur outside North America. Ptilineurus was 

later recorded from Virginia and is currently the only genus 

representing Dryophilinae LeConte in North America (Philips 2002). Presently, North American Ptilininae, north of 

Mexico includes one genus and nine species (White 1982, 

Philips 2002). Specific curation of adult-mounted specimens 

of Ptilininae is usually not necessary as they are not highly 

contractile and generally die with the necessary structures 

exposed. 

Ptilinus was first thought to be a transitional form between 

Anobiinae and Bostrichidae (LeConte 1861, Casey 1898) 

based on resemblance to certain bostrichid genera in terms 

of body form, sculpture, and the structure of the prothoracic 

tibiae (Fall 1905). This was later discredited by Fall (1905) 

who reported the resemblance as largely superficial and 

stated “there can be no doubt that Ptilinus is a true Anobiide, and it appears to me to be most closely allied to the 

central group—the Anobiini—from which it has diverged in 

about the same degree as have Petalium and Eupactus, and 

is equally hard to place.” White (1971a) stated Ptilininae 

are “likely an offshoot of a Euceratocerus-like anobiid” and 

exhibit “little change in general form from members of the 

more primitive genera of Anobiinae.” Thus, Ptilininae was 

placed between the Anobiinae and Xyletininae in North 

American fauna (Philips 2002).

Genus Ptilinus Mueller

Type Species: Ptilinus fuscus Geoffroy 1972: 64 (designated 

by Lucas 1920: 557).

Ptilinus Mueller 1764: xii. 

Geoffroy (1762) established this genus for Ptinus pectinicornis Linnaeus, but his work was rejected by the International Commission on Zoological Nomenclature (ICZN) 

because he did not use the requisite binary system of 

nomenclature (Acciavatti 1972). Mueller (1764) was next 

to describe this genus, although no species were assigned 

to Ptilinus, his description validated the name (Acciavatti 

1972). 

The first major synopsis of the North American species 

of Ptilinus was compiled by Casey (1898) in which he 

described five new species: Ptilinus acuminatus, Ptilinus 

flavipennis, Ptilinus lobatus, Ptilinus pruinosus, and Ptilinus ramicornis, in addition to Ptilinus ruficornis Say and 

Ptilinus basalis LeConte. In 1905, Fall tentatively included 

Tomicus thoracicus Randall in Ptilinus (White 1982). Later, 

the European species, P. pectinicornis (Linnaeus), was recorded from New York State by Simeone (1961), bringing 

the total number of species known to occur in North America, north of Mexico, to nine (White 1982). 

Two species have been found in Wisconsin, with one species 

that may eventually be collected. This includes P. ruficornis, 

the second most frequently encountered wood-feeding anobiid in the northeastern United States (White 1982). Ptilinus 

pruinosus has not yet been recorded from the state but is 

included in the key as it has been found in Ontario, Ohio, 

and Indiana, and may occur in Wisconsin. Males of this species were not available for examination during this study, so 

characters described in the key regarding antennal structures 

are taken from Fall’s (1905) revision. 

This genus is in need of revision as it has not been seriously 

treated taxonomically since Fall’s work in 1905. The characters used in his key pertain almost exclusively to characteristics of the male antennae, with little to distinguish female 

specimens of Ptilinus, particularly P. lobatus from P. pruinosus. In addition, the couplet separating these two species 

in Fall’s (1905) key contradicts the description of P. pruinosus given, by separating P. pruinosus from P. lobatus based 

on the prothorax being narrower than the elytra. However, 

in his description he characterized the prothorax as being 

“fully as wide as the elytra” for P. pruinosus. Casey (1898) 

differentiated females of these two species by the shape of 

the scutellum and form of the epipleurae, although these 

distinctions were not utilized or addressed by Fall (1905). In 

Casey’s (1898) work, the scutellum of P. lobatus was said to 

be “elongate, finely and densely rugose” and the “epipleurae 

gradually wider at base,” compared to P. pruinosus which 

was said to have the “scutellum quadrate, coarsely rugose,” 

and the “epipleurae rapidly wider at base.” Examination 

of female specimens of P. lobatus and P. pruinosus from 

the IRCW and FMNH did not seem to provide additional 

insight into these differences. To determine the potential 

usefulness of the female genitalia in species level determinations, three P. ruficornis females were dissected. Although 

females are known to oviposit in pores of hardwoods, the 

genitalia did not appear to be strongly sclerotized, and their 

potential for offering diagnostic characters was not further 

examined. Therefore, females of P. lobatus and P. pruinosus

may not be separated unless collected with a male specimen, 

which is unfortunate because many of the Ptilinus specimens collected are ovipositing females. The structure of the 

female anterior pronotal asperities may eventually provide 

useful taxonomic characters, but this requires further study 

(see diagnosis for P. lobatus).
General Technical Report FPL–GTR–209

40

Larvae of Ptilinus develop in a variety of hardwoods (White 

1982), whereas adults are commonly collected using flight 

intercept and Lindgren funnel traps. As stated above, large 

numbers of adult females may be collected on dead, standing hardwood trees, where they are commonly seen ovipositing on the same wood from which they emerged (Acciavatti 1972). 

Males and females may be easily separated based on their 

sexually dimorphic antennae, which are strongly pectinate 

in males and serrate in females (Figs. 36, 37, 156–158). 

Males also tend to be smaller and less robust than females. 

The pronotal asperities appear to be sexually dimorphic as 

well; those of females strongly produced on the apical 

pronotal margin, which likely evolved to facilitate movement through tunnels in the wood created by the female 

during oviposition (Figs. 92, 159, 160). Anterior pronotal 

asperities in the males tend to be much less strongly developed (Figs. 157, 158). 

Species of Ptilinus can be easily distinguished from all other 

Wisconsin Ptinidae by the following combination of characters: mandibles distant from metathoracic ventrite during 

body retraction (Figs. 156, 158, 160); antennae sexually 

dimorphic (Figs. 36, 37, 157–160); pronotum with asperities (Figs. 92, 159, 160); outer margin of prothoracic tibiae 

finely toothed, terminating in a large apical tooth (extracted 

in part from Philips 2002).

Key to the Wisconsin Species of Adult Ptilinus

[Modified from Casey 1898, Fall 1905, and White 1962a]

1 Lateral pronotal margins fine, but well defined and even throughout (Figs. 158, 160); subapical 

 transverse carina of last ventrite distinct in both sexes (Fig. 78); antennal rami of male longer, 

 that of the third segment about twice the length of the segment, that of the fourth antennomere 

 six or seven times the length of the segment (Fig. 36) ..................................................................ruficornis Say (p. 41)

1’ Lateral pronotal margins not well defined, comprised of granules (Fig. 156); subapical ventral 

 transverse carina nearly or entirely absent in both sexes; antennae of male not as above .............................................2

2 (1’) Male with ramus of third antennomere not longer than the segment itself (Fig. 156); 

 ramus of fourth antennomere 3–3.5X length of the segment.................................................. lobatus Casey (p. 40)

2’ Males with ramus of the third antennomere 0.5X length of the segment itself; ramus of 

 fourth antennomere nearly 5X the length of the segment.....................................................................pruinosus Casey

Ptilinus lobatus Casey

(Figs. 155, 156; Map 26)

[Synonymy modified from White 1982]

Ptilinus lobatus Casey 1898: 62.

Ptilinus serricollis Say 1823: 186 (White 1970).

Capsule Description (Figs. 155, 156)—Length: 3.0–

3.3 mm. Width: 1.1–1.3 mm. Integument Color: dark 

reddish-brown to black; maxillary and labial palpi, and 

antennae yellowish-orange to yellowish-brown; pronotum 

sometimes darker than elytra; legs reddish-brown to reddish-black, tarsi yellowish. Body Form: cylindrical, robust, 

2.6X longer than wide. Vestiture: pubescence yellowish; moderately dense, short, recumbent. Head: antennae 

11-segmented, those of male strongly pectinate, 3rd antennomere with ramus equal to that of length of the segment, 

4th antennomere about 3.5X the length of the segment, antennae of female strongly serrate; surface granulate. Pronotum: subequal in width to the elytra; appearing compressed 

toward anterior margin; surface with numerous asperities 

anteriorly, asperities decreasing in size laterally (less distinctive in male); lateral pronotal margins not well defined, 

composed of granules; pronotal base with a slightly raised 

and shining longitudinal carina. Elytra: parallel-sided; 

humeri discernible, not prominent; surface irregularly punctate, without striae; intervals slightly raised. Metathoracic 

Ventrite: not excavate for reception of mesothoracic legs; 

posteriorly with a deep longitudinal sulcus, terminating 

around middle of disk, sulcus mostly smooth and devoid 

of setae; surface densely punctate. Legs: not received in 

ventral excavations; margin of each prothoracic tibia finely 

toothed, terminating in a large apical tooth; metathoracic 

coxae grooved for metathoracic legs. Abdomen: with 5 

ventrites; 5th ventrite with subapical transverse carina indistinct to lacking.

Diagnosis—Ptilinus lobatus may be distinguished from all 

other Wisconsin Ptinidae by a combination of the following 

characters: mandibles distant from metathoracic ventrite 

during body retraction (Fig. 156); antennae of males strongly pectinate with ramus of third antennomere not longer than 

the length of the segment (Fig. 156), and the fourth antennomere about 3–3.5X the length of the segment, females 

with serrate antennae; pronotum with discal asperities; pronotal lateral margins not well defined, made up of granules 

(Fig. 156); outer margin of prothoracic tibiae finely toothed, 
Death-Watch and Spider Beetles of Wisconsin

41

terminating in a large tooth at apex; last abdominal ventrite 

without a distinct transverse carina (extracted in part from 

White 1962a and Philips 2002). 

Wisconsin adult males of P. lobatus are slightly different 

than those described by Fall in that the fourth antennomere 

is about three and a half times the length of the segment 

compared with “scarcely three times the length of the joint,” 

as stated by Fall (1905). This could simply be the result of 

differences in measuring techniques and is not thought to 

be significant. Adult males of P. pruinosus have the fourth 

antennomere “nearly five times the length of the joint,” thus, 

the Wisconsin specimens fall closer to P. lobatus.

As mentioned in the generic synopsis, females of P. lobatus

are not readily distinguished from those of P. pruinosus

unless accompanied by a male. Females of these two species may eventually be separated based on the form of the 

anterior asperities of the pronotum, as comparison of this 

structure on P. ruficornis and P. lobatus females did seem to 

show a significant difference in arrangement. In females of 

P. ruficornis, these asperities were fewer and closer together, 

compared to those of female specimens of P. lobatus, which 

were more numerous and spread apart, gradually decreasing 

in size laterally.

Natural History—Little has been reported pertaining to 

the natural history of this species. In a study of saproxylic 

insects associated with dead wood or woody fungi, Jacobs 

et al. (2007) reported P. lobatus to be a significant indicator 

species of a deciduous-dominated forest habitat, meaning 

they found a strong association between this species and 

certain deciduous trees. In Wisconsin, a male and a female 

specimen of P. lobatus were collected from a “termite log.” 

The third male specimen examined had no specific collection data.

Phenology—Two adults of P. lobatus were recorded in 

Wisconsin during mid-May and one in mid-June.

Distribution—Ptilinus lobatus occurs mainly in south central North America from New Mexico and Colorado, and 

east into Nebraska, Kansas, and Missouri (White 1982). 

Majka (2007a) reported this species from Nova Scotia and 

Ontario. In this study, specimens were examined from two 

Wisconsin counties; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 26)—The three specimens of 

P. lobatus examined during this study were recorded from 

the following localities: Door Co. (1): No other locality 

data; Rock Co. (2): Janesville.

Ptilinus ruficornis Say

(Figs. 9, 36, 37, 78, 92, 157–160; Map 27)

[Synonymy modified from White 1982] 

Ptilinus ruficornis Say 1823: 186.

Ptilinus bicolor Melsheimer 1846: 308.

Capsule Description (Figs. 9, 36, 37, 78, 92, 157–160)—

Length: 2.8–4.5 mm. Width: 1.1–1.7 mm. Integument 

Color: light or dark reddish-brown to black; maxillary and 

labial palpi and antennae yellowish-orange to yellowishbrown; pronotum sometimes darker than elytra; legs and 

tarsi reddish-brown to reddish-orange. Body Form: cylindrical, robust, 2.7X longer than wide. Vestiture: pubescence 

yellowish; moderately dense, short, recumbent. Head: antennae 11-segmented, that of male strongly pectinate, 

3rd antennomere with ramus nearly 2X the length of the 

segment, antennae of female strongly serrate; surface granulate-punctate. Pronotum: as wide as, to slightly wider than 

elytra; appearing compressed toward anterior margin; surface with numerous asperities anteriorly, becoming smaller 

laterally (less distinctive in males); lateral margins complete 

and even throughout; base of pronotum with a slightly 

raised and shining longitudinal carina. Elytra: parallel 

sided; humeri discernible, not prominent; surface punctate, 

without striae; punctures forming indistinct rows. Metathoracic Ventrite: not excavate for reception of mesothoracic 

legs; posteriorly with a deep longitudinal sulcus, terminating 

around middle of disk, sulcus mostly smooth and devoid of 

setae; surface densely punctate. Legs: not received in ventral excavations; outer margin of prothoracic tibiae finely 

toothed, terminating in a large apical tooth; metathoracic 

coxae grooved for reception of metathoracic legs. Abdomen: with 5 ventrites; 5th ventrite with a distinct subapical 

transverse carina.

Diagnosis—Ptilinus ruficornis may be distinguished from 

all other Wisconsin Ptinidae by a combination of the following characters: mandibles distant from metathoracic ventrite 

during body retraction (Figs. 158, 160); antennae strongly 

pectinate with ramus of third antennomere twice the length 

of the segment (males) (Fig. 36) or serrate (females) 

(Fig. 37); pronotum with asperities (Figs. 92, 157–160); 

lateral pronotal margins fine, well defined and even throughout, not made up of granules (Figs. 158, 160); outer margin 

of prothoracic tibiae finely toothed, terminating in a large 

apical tooth; last abdominal ventrite with distinct transverse 

carina (Fig. 78) (extracted in part from Philips 2002).

Natural History—Ptilinus ruficornis, excluding Ptininae, is 

perhaps the “most abundant species of Anobiidae breeding 

in seasoned wood of American beech and sugar maple in 

Northern Hardwood Forests” (Acciavatti 1972). Both Simeone (1960) and Acciavatti (1972) examined the life history 

of this economically important species in the northeastern 

United States. Work by Acciavatii investigated viability 

of adult males and females, emergence factors, courtship 

behavior, flight ability, temporal activity, orientation of females to potential oviposition sites, pre-oviposition boring, 

effect of chilling on larval development, and parasitoids of 

P. ruficornis larvae. This work recorded the abundance of 

males and females during five different behaviors: emerging, walking on brood wood, flight, landing on un-infested 
General Technical Report FPL–GTR–209

42

wood, and female boring. Acciavatti (1972) concluded 

P. ruficornis females are more abundant in all behavioral 

situations, with the exception of emergence, where numbers 

of males and females were nearly equal. He also determined 

females live longer on average than males, although mated 

females showed a reduction in viability compared to unmated females (Acciavatti 1972). These results suggested adults 

have the greatest flight ability within one day of emergence, 

with mating usually occurring at emergence when higher 

proportions of males are present (Acciavatti 1972). 

Acciavatti (1972) examined the behavior of solitary males 

and females of P. ruficornis as well as sexual display behavior when they were combined. Females were observed to 

“raise and lower their abdomens periodically” and during 

these movements, “a glandular structure protruded from 

beneath the pygidium each time the abdomen was raised.” 

When females were placed in a container with males, 

Acciavatti (1972) observed the following:

Upon encountering a displaying female, 

a male responded with rapid body undulations for 1 to 2 seconds, extension 

of the aedeagus and excessive activity 

culminating in mating attempts. Antennal vibration over the female’s prothorax 

while grasping her elytra with his legs 

accompanied these attempts. Displaying 

males attempted to mate with other males 

as well. Apparently, once males respond to 

a displaying female, the presence of other 

adults regardless of their sex is adequate 

to stimulate mating attempts.

After mating has occurred, the female may seek out suitable 

wooden material in which to lay her eggs, or oviposit on 

the same wood from which she emerged (Acciavatti 1972). 

Females were not shown to be attracted to infested wood, 

although Acciavatti’s (1972) results suggested flight was 

arrested by chemical stimuli from the wood and other boring 

females once a female landed on a substrate. The ovipositor and sensory pits on antennomeres 4–10 are though to 

act as olfactory receptors for such chemicals (Acciavatti 

1972). Both Simeone (1960) and Acciavatti (1972) observed 

females bore back into the wood to complete oviposition 

after emergence. Females create a hole along the wood grain 

by use of their mandibles (Fig. 9). After the hole is deep 

enough, the female turns around, backs into the hole so that 

her head is directed towards the entrance, and inserts her 

ovipositor deeply within the wood cells (Acciavatti 1972). 

Larvae of this species were described by Böving (1954) for 

specimens collected from Populus deltoides Bartram, although this description also included three other species: 

P. basalis, P. fuscus, and P. pectinicornis. Specimens of 

P. ruficornis have been recorded only from hardwoods, including Acer saccharum Marshall, Acer rubrum Linnaeus, 

Betula alleghaniensis Britton, Fagus grandifolia Ehrhart., 

Tilia americana Linnaeus, and Quercus sp. (Harrington 

1887, Runner 1919, Champlain and Knull 1922, Simeone 

1960, Acciavatti 1972). Packard (1890) reported this species to be rather common, attacking both live and dead trees, 

and boring into exposed wood in which the bark has been 

partially stripped away. Other larval food materials include 

wild cultivated cherries, Prunus spp., eastern hophornbeam, 

Ostrya virginiana (Miller) K. Koch (Hopkins 1893); American sycamore, Platanus occidentalis Linnaeus, and mesquite 

Prosopis sp. (Craighead 1950); as well as “seaweed and 

dead beech” (Leng 1928, Acciavatti 1972). According to Acciavatti (1972), this species was reported from “dry, exposed 

wood of blazed, peeled and dead trees (Harrington 1887, 

1897), sawlogs and cordwood (Packard 1890), flooring 

(Felt 1905), woodwork and stored wood (Craighead 1950) 

and structural timbers and furniture (Mallis 1960).” Within 

buildings, infested wood was found to have a relatively high 

average moisture content of 16.9% (Simeone 1960).

The tendency of P. ruficornis to utilize woody substrates 

causes it to be economically significant in wood and wood 

products (Simeone 1960). In fact, damage from this species 

is often referred to as “powder-posting” due to the frass exuded from emergence holes in the wood (Acciavatti 1972). 

Both larvae and to a lesser degree adults damage wooden 

materials that can increase over time from continuous reinfestation within the same wood material (Packard 1890, 

Acciavatti 1972). A rhipiphorid beetle, Pelecotoma flavipes

Melsheimer, known to feed on wood-inhabiting insects, is a 

parasitoid of P. ruficornis larvae (Acciavatti 1972), although 

its numerical effects on P. ruficornis populations is not well 

understood.

Although P. ruficornis was found to be relatively common 

throughout Wisconsin, it was not found to be a significant 

pest of structures or stored wooden products in the state, 

possibly because of the higher moisture conditions required 

by this species. Of the 215 specimens collected, only about 

3% were collected indoors, with no indication whether the 

beetle emerged from structural wood or from something 

brought into the home. 

Approximately a third of specimens (36%) were handcollected, either crawling on or boring into bare standing or 

fallen dead hardwoods, including Acer sp. and a box elder 

tree, Acer negundo Linnaeus, that had been cut down over 

the previous winter. A number of specimens were also collected boring into the heartwood of a dead, cut Quercus sp. 

log, although females appeared to bore into sapwood as 

well. Literature and collections indicate P. ruficornis occurs 

mainly in hard, dead, debarked hardwoods; however, one 

series was collected from a dead, standing Quercus tree that 

still retained some of its bark, although partially separated 

from the tree trunk. One specimen was swept from “vegetation along path opening,” one was beaten from “vegetation 
Death-Watch and Spider Beetles of Wisconsin

43

along R.R. tracks on Lake Superior,” three were collected 

crawling “on trunk of maple,” one from a “cut-site log 

pile at night,” and one specimen was found on a leaf of a 

shrub. Adults of P. ruficornis were also readily obtained by 

trapping, including flight intercept, Lindgren funnel, and 

Townes–Malaise traps, some of which were baited with 

ipsdienol, cantharidin, or ethanol, although these did not 

appear to be significant attractants for the species. Finally, 

four specimens were taken at a Hg vapor lamp at night in a 

“one-year old hardwood cut site.”

Phenology—Simeone (1960) found P. ruficornis to be univoltine with eggs generally laid in August, larval development until late May, pupation in June, and adult emergence 

from June to August. Emergence may, however, be delayed 

when conditions are not favorable (Acciavatti 1972). 

Emergence of the maximum number of adult P. ruficornis

individuals was determined by Acciavatti (1972) to occur 

between the 25th and 30th of June, coinciding with maximum air temperature. Daily emergence number was said to 

“depend on present as well as on previous wood temperatures.” Both studies were conducted in the northeastern part 

of the United States. 

In Wisconsin, adults of P. ruficornis were recorded from 

mid-May to late July, with the majority of individuals occurring during June. A few specimens that emerged indoors 

were recorded from late March. Additional specimens were 

recorded from mid-February and late March, likely from 

indoors as well, although this was not directly stated on the 

label.

Distribution—Ptilinus ruficornis occurs widely across central and eastern North America, having been collected from 

Alberta and Ontario, Canada, and in the United States from 

Kansas, Iowa, and Wisconsin, east to New York and Massachusetts, and south to Kentucky and Alabama (White 1982). 

Larvae described by Böving (1954) included specimens obtained from Wisconsin. During the present study, specimens 

were recorded from 24 counties throughout the state.

Wisconsin Records (Map 27)—The 215 specimens of P. ruficornis examined during this study were recorded from the 

following localities: State only (5); Watertown; Ashland 

Co. (1): Marina Peninsula Park; Dane Co. (30): Madison–

U.S.G.S. National Wildlife Health Center; Picnic Point; 

Private Property–Town of Blue Mounds; Swamp Lover’s 

Inc.; No other locality data; Eau Claire Co. (2): Eau Claire 

County Forest; Florence Co. (5): Private Property; Forest 

Co. (24): 10.4 mi. North of FR 2183 and HWY 55; Grant 

Co. (1): Wyalusing State Park; Green Co. (47): Abraham’s 

Woods SNA; Browntown Oak Forest SNA; Iowa Co. 

(1): Ridgeway Pine Relict SNA; Jackson Co. (1): No additional label data; Lafayette Co. (3): Wedel property– 

~3 mi. North of Argyle; Marathon Co. (3): Big Eau Pleine 

Woods SNA–Big Eau Pleine County Park; Marinette Co. 

(1): Marinette County Beech Forest SNA; Menominee Co. 

(2): Menominee Tribal Enterprises; Milwaukee Co. 

(13): Cudahy Woods SNA; Whitefish Bay; No other locality 

data; Ozaukee Co. (2): Mequon–Riverlake Road Natural 

Area; Racine Co. (12): Renak–Polak Maple–Beech Woods 

SNA; Richland Co. (3): LWRSWA Lone Rock Unit; Rock 

Co. (2): Private Property–1.7 mi. NW Janesville; Sauk Co. 

(22): Spring Green–Bakken’s Pond; Hemlock Draw TNC; 

Shawano Co. (1): 1.3 mi. NE Wittenberg; Trempealeau 

Co. (18): Perrot State Park; Walworth Co. (1): Kettle Moraine Oak Opening SNA; Washburn Co. (13): Berry Road–

Near Nice Lake–4.5 mi. NW of Birchwood; Wood Co. 

(2): Powers Bluff SNA.

Subfamily Xyletininae

Xyletininae was proposed by Gistel (1856) according to 

Lawrence and Newton (1995), although Thomson (1859) 

is sometimes given credit for the subfamilial name (e.g., 

Español 1992). Within Xyletininae, taxonomy of species in 

Xyletinini has been particularly problematic. White (1985) 

stated, “it is surely evidence of difficult taxonomy when 

the history of a group of species shows much confusion in 

suprageneric and generic assignments.” The genera to which 

he referred include Xyletinus Latreille, Euvrilletta Fall, and 

Vrilletta LeConte. 

Fall’s (1905) generic description indicated Euvrilletta was 

structurally similar to Vrilletta, but differentiated the two 

based on characters of the antennae and maxillary palpi. In 

1985, White re-examined generic concepts of Euvrilletta

and Xyletinus, placing elongate-bodied species with large 

eyes in Euvrilletta and stout-bodied species with smaller 

eyes in Xyletinus. Subsequent work limited Vrilletta to species with small eyes and antennal segments 4–10 strongly 

serrate to pectinate. This may lead them to be difficult to 

distinguish from other genera in Xyletininae. The relationships among the three genera should be re-evaluated so that 

species determinations can be made with a greater amount 

of certainty. 

Xyletininae begin to show a distinct reduction of the proand mesosternum, allowing for greater contraction of the 

head and enabling the mandibles to reach, or nearly reach, 

the metathoracic ventrite in repose (less obvious in Vrilletta and Euvrilletta, compared to Lasioderma and most 

species of Xyletinus). This trend becomes still more defined 

in phylogenetically more derived subfamilies such as the 

Dorcatominae and Mesocoelopodinae. Xyletininae in North 

America north of Mexico currently includes six genera and 

50 species (White 1985, Philips 2002). Four genera and 

seven species were confirmed from Wisconsin in the present 

study. 

Larvae of most Xyletininae bore into dead hardwoods or 

softwoods and therefore may cause damage to woodwork 

and structural wood of buildings (White 1982). Xyletininae 

contains two well-known species of economic importance, 
General Technical Report FPL–GTR–209

44

the first being the cosmopolitan species, Lasioderma serricorne (Fabricius), which breeds in a variety of stored 

products, most notably tobacco. Another economically significant species is Euvrilletta peltata (Harris), considered 

the most common anobiid in the southeastern United States 

(Ebeling 1978). Both L. serricorne and E. peltata are discussed further in the descriptions that follow.

Members of North American Xyletininae may be distinguished from most other Ptinidae by having the mandibles 

reach or nearly reach the metathoracic ventrite in repose 

and the first abdominal ventrite not grooved to receive the 

metathoracic legs (Fig. 162) (extracted in part from Philips 

2002). However, in Mesocoelopodinae, the genus Neosothes

White also exhibits these characters and is difficult to separate from the Xyletininae, except by its distribution, being 

known only as far north as Baja California (White 1975). 

Proper curation of specimens in this subfamily involves 

drawing out the antennae so that the length of various segments may be compared. Prothoracic and mesothoracic legs 

should also be pulled away from the body so that the metathoracic ventrite is visible. In certain cases, male genitalia 

may need to be extracted and examined.

The following key should be used with caution as it pertains 

quite specifically only to species possible for the Wisconsin 

genera presented. 

Key to the Wisconsin Genera of Adult Xyletininae

[Modified from Philips 2002]

1 Metathoracic ventrite abruptly declivous and transversely carinate anteriorly ..................................Lasioderma (p. 51)

1’ Metathoracic ventrite not abruptly declivous and transversely carinate anteriorly ........................................................ 2

2 (1’) Combined length of last 3 antennal segments equal to or longer than all preceding 

 combined (Fig. 39); elytral intervals strongly convex (Figs. 167, 168) ............................................Vrilletta (p. 47)

2’ Combined length of last 3 antennal segments at most equal in length to preceding 4–7 segments; 

 elytral intervals less convex............................................................................................................................................ 3

3 (2’) Eyes large, separated by ≤3.5X their width when viewed from the front (Fig. 88) .......................Euvrilletta (p. 44)

3’ Eyes small, separated by ≥4.0X their width when viewed from the front.............................................Xyletinus (p. 48)

Genus Euvrilletta Fall

[Synonymy modified from White 1982, 1985] 

Type Species: Euvrilletta xyletinoides Fall 1905: 

196 (by monotypy).

Oligomerodes Fall 1905: 161. 

Euvrilletta Fall 1905: 196.

Oligomeroides Fall; Pic 1912a: 81 (lapsus calami).

Euvrilleta Fall; Van Dyke 1946: 85 (lapsus calami).

Euvrilletta was proposed by Fall (1905) for E. xyletinoides. 

In the same revision, he erected Oligomerodes, in Anobiini, 

for two species: Oligomerodes occidentalis and Oligomerodes catalinae, which were later synonymized as species 

of Euvrilletta by White (1976b).

Although White significantly improved the taxonomy of this 

genus, species determinations still remain problematic. The 

key to North American Euvrilletta (White 1985) relies on 

distribution and relative lengths of the antennal segments 

for determinations with few dissections of male genitalia. 

Because the length of the last three antennal segments in 

most Anobiidae auctorum tends to be sexually dimorphic, 

this character may lead to difficulties. In addition, given that 

collection of members of Xyletininae is rather uncommon, 

distributions are not well known, and should only be used in 

a key in conjunction with other characters. Unfortunately, it 

is not possible at this time to make significant changes to the 

existing keys. Further examination of male genitalia should 

be conducted to evaluate the extent of variation present in 

species otherwise difficult to separate by present means. 

Euvrilletta may be distinguished from all other Wisconsin 

Xyletininae by a combination of the following characters: 

eyes large and separated by less than 3.5X their width when 

viewed from the front; metathoracic ventrite not abruptly 

declivous and without a transverse carina (extracted in part 

from White 1985, Philips 2002).

Fifteen species of Euvrilletta are known from North America, north of Mexico, three of which occur in Wisconsin. 

Specimens are most frequently taken using UV or Hg light, 

but they may also be collected using passive Lindgren or 

flight intercept traps.
Death-Watch and Spider Beetles of Wisconsin

45

Key to the Wisconsin Species of Adult Euvrilletta

[Modified from White 1985]

1 Last 3 antennomeres combined equal in length to preceding 6 segments; terminal 

 antennomere nearly 3X longer than wide in both sexes (Figs. 40, 41)............................................brevis White (p. 45)

1’ Last 3 antennomeres combined equal in length to preceding 4–5 segments; terminal 

 antennomere <3X as long as wide in both sexes...........................................................................................................2

2 (1) Lateral pronotal margin narrow and not reflexed; terminal maxillary palpomere elongate, 

 >2X longer than wide, feebly triangular (Fig. 59).....................................................................peltata (Harris) (p. 46)

2’ Lateral pronotal margin broad and reflexed; terminal maxillary palpomere broadly triangular, 

 about 1.5X longer than wide. (Fig. 60)......................................................................................... harrisii (Fall) (p. 46)

Euvrilletta brevis White

(Figs. 40, 41, 161, 162; Map 28)

[Synonymy modified from White 1982] 

Euvrilletta brevis White 1960: 235.

Xyletinus brevis (White); White 1969c: 254.

Euvrilletta brevis was described by White (1960) from three 

males collected in Adams Co., Ohio. White (1969c) briefly 

considered this species as a member of Xyletinus before his 

revision of the two genera (White 1977b, 1985).

Capsule Description (Figs. 40, 41, 161, 162)—Length: 

3.7–4.0 mm. Width: 1.5–1.8 mm. Integument Color: light 

reddish-brown to dark reddish-brown throughout; pronotum 

and elytral base sometimes darker; maxillary and labial 

palpi, antennae, and tarsi reddish-yellow to reddish-brown. 

Body Form: elongate, robust, 2.3X longer than wide. Vestiture: body and appendages with moderately dense, short, 

yellowish, recumbent pubescence. Head: terminal segment 

of each maxillary palpus elongate, 2–3X longer than wide, 

inner lateral margin rounded; eyes moderately large, separated by <3.5X the width of the eye when viewed from the 

front; antennae 11-segmented, serrate, segments 3–8 similar 

in size and shape, 9th segment slightly shorter than combined length of 7 + 8, segments 9–11 elongate (moreso in 

male), about equal in length to the combined length of 3–8; 

terminal antennomere 3X longer than wide; surface finely, 

densely punctate. Pronotum: evenly convex; with short, 

feeble basal longitudinal carina; lateral margin narrowly 

reflexed; surface finely granulate, punctate. Elytra: each 

elytron with 10 complete to nearly complete striae, not appearing as rows of punctures; striae weakly impressed, intervals nearly flat. Metathoracic Ventrite: not excavate for 

reception of the mesothoracic legs; anterior raised margin of 

the intercoxal process arcuate; posteriorly with a darkly 

pigmented, longitudinal sulcus medially, extending 

0.75X length of disk; surface finely, densely punctate. 

Legs: not received in ventral excavations; metathoracic 

coxae grooved to receive metathoracic legs. Abdomen:

with 5 ventrites.

Diagnosis—Euvrilletta brevis may be separated from all 

other Wisconsin Xyletininae by a combination of the following characters: terminal segment of each maxillary palpus 

elongate, at least twice as long as wide; eyes large, separated 

by no more than 3.5 times the width of the eye when viewed 

from the front; antennomeres 9–11 elongate, equal in length 

to combined length of 3–8, terminal antennal segment nearly 3X longer than wide (Figs. 40, 41); metathoracic ventrite 

not declivous anteriorly (extracted in part from White 1985, 

Philips 2002). 

In Wisconsin, specimens of E. brevis are most similar to 

those of Euvrilletta peltata (Harris) in the form of the terminal maxillary palpomere and shape of the pronotum. The 

combined length of antennomeres 9–11 is the only positive 

way to differentiate the two species, although this may 

also prove problematic in the future as more variation is 

discovered. 

Natural History—The natural history of this species is 

unknown as few records have been published from North 

America. The majority of Wisconsin specimens were collected at light, either from a light trap or at a UV or Hg vapor lamp. The two specimens collected at a flight intercept 

trap baited with cantharidin were certainly incidental with 

respect to the bait. 

Phenology—White (1965) recorded E. brevis adults from 

South Dakota during the months of June, July, and August, 

and specimens collected from Ohio in June (White 1962a). 

In Wisconsin, adults were collected from late June to midJuly.

Distribution—Euvrilletta brevis has been recorded from 

South Dakota, Ohio, and South Carolina (White 1982). This 

species has been previously published to occur in Wisconsin 

(White 1982). During this study, specimens were recorded 

from six Wisconsin counties.
General Technical Report FPL–GTR–209

46

Wisconsin Records (Map 28)—The 12 specimens of 

E. brevis examined during this study were recorded from the 

following localities: Dane Co. (6): Private Property–Cottage Grove; Private Property–Deerfield; Florence Co. 

(1): No other locality data; Milwaukee Co. (2): Cudahy 

Woods SNA; Richland Co. (1): No other label data; Sauk 

Co. (1): Hemlock Draw TNC; Wood Co. (1): Griffith St. 

Nursery.

Euvrilletta harrisii (Fall)

(Figs. 42, 43, 60, 88, 163, 164; Map 29)

[Synonymy modified from White 1982, 1985] 

Xyletinus harrisii Fall 1905: 201.

Euvrilletta harrisii (Fall); White 1985: 185.

Euvrilletta harrisii was described by Fall (1905) for specimens differing from the morphologically similar E. peltata. 

Therefore, collections of E. peltata determined prior to 1905 

probably also contain specimens of E. harrisii. 

Capsule Description (Figs. 42, 43, 60, 88, 163, 164)—

Length: 3.6–4.3 mm. Width: 1.6–1.9 mm. Integument 

Color: light reddish-brown to dark reddish-brown throughout; maxillary and labial palpi and antennae reddish-yellow 

to reddish-brown; legs orange-brown to reddish-brown. 

Body Form: elongate, robust, 2.2X longer than wide.

Vestiture: body and appendages with short, yellowish, 

moderately dense, recumbent pubescence. Head: terminal 

segment of each maxillary palpus broadly triangular, about 

1.5X as long as wide; eyes large, separated by <3.5X the 

width of the eye when viewed from the front; antennae 

11-segmented, serrate, antennomeres 3–10 triangular, segment 3 elongate-triangular, segment 11 elongate, segments 

9–11 equal in length to the 4–5 preceding combined; surface 

finely, densely punctate. Pronotum: strongly convex; lateral 

margin of pronotum broad and reflexed; surface granulatepunctate. Elytra: each elytron with 10 complete to nearly 

complete fine, and somewhat deep striae; intervals weakly 

convex. Metathoracic Ventrite: not excavate for reception of the mesothoracic legs; anterior raised margin of the 

intercoxal process broadly arcuate to flat; posteriorly with a 

darkly pigmented, longitudinal sulcus medially, extending 

0.75X length of disk; surface finely, densely punctate. 

Legs: not received in ventral excavations; metathoracic 

coxae grooved to receive metathoracic legs. Abdomen:

with 5 ventrites.

Diagnosis—Euvrilletta harrisii may be separated from all 

other Wisconsin Xyletininae by a combination of the following characters: terminal maxillary palpomere broadly triangular, length 1.5X width (Fig. 60); eyes large, separated by 

no more than 3.5X width of the eye when viewed from the 

front (Fig. 88); antennomeres 9–11 slightly enlarged, equal 

in length to the preceding 4–5 segments combined, terminal 

antennomere usually less than twice as long as wide 

(Figs. 42, 43); lateral margin of the pronotum broad and 

reflexed (extracted in part from White 1985, Philips 2002). 

Specimens of E. harrisii may be immediately distinguished 

from the other two Wisconsin species by the form of the terminal maxillary palpomere and lateral pronotal margin.

Natural History—Unlike E. peltata, E. harrisii is said to be 

uncommonly collected in North America and is therefore 

thought to be of little economic significance. Champlain and 

Knull (1922) reported specimens of E. harrisii reared from 

dead oak. In Wisconsin, specimens of E. harrisii were collected at Lindgren funnel and flight intercept traps as well as 

at a Hg vapor lamp. One specimen was found crawling on 

the outside of a hanging flight intercept trap. 

Phenology—Adult specimens of E. harrisii were recorded 

in Wisconsin from mid-July to early August.

Distribution—Euvrilletta harrisii occurs throughout the 

northeastern United States from New Jersey, New York, 

Massachusetts, and New Hampshire, and west into Kentucky, Ohio, Pennsylvania, and Michigan (White 1982). In 

this study, specimens were examined from four Wisconsin 

counties; they constitute a NEW STATE RECORD and 

new northwestern range extension of the known distribution 

for the species.

Wisconsin Records (Map 29)—The eight specimens of E. 

harrisii examined during this study were recorded from the 

following localities: Clark Co. (1): Schmidt Maple Woods 

SNA; Fond du Lac (1): Waupun Park Maple Forest SNA; 

Milwaukee Co. (4): Cudahy Woods SNA; Sheridan Park; 

Sauk Co. (2): Hemlock Draw TNC. 

Euvrilletta peltata (Harris)

(Figs. 59, 165, 166; Map 30)

[Synonymy modified from White 1962a, 1982, 1985] 

Anobium peltatus Harris 1836: 75.

Xyletinus peltatus (Harris); LeConte 1865: 237.

Euvrilletta peltata (Harris); White 1985: 185.

Capsule Description (Figs. 59, 165, 166)—Length: 3.7–

4.6 mm. Width: 1.6–2.2 mm. Integument Color: yellowish-brown to dark reddish-brown throughout; maxillary 

and labial palpi and antennae reddish-yellow to reddishorange; legs orange-brown to reddish-brown, tarsi lighter. 

Body Form: elongate, 2.2X longer than wide. Vestiture:

body and appendages with short, yellowish, moderately 

dense, recumbent pubescence. Head: terminal segment of 

each maxillary palpus elongate, feebly expanded laterally, 

2–2.5X as long as wide; eyes large, separated by <3.5X 

the width of the eye when viewed from the front; antennae 

11-segmented, serrate, antennomeres 3–8 triangular, segment 3 elongate-triangular, segment 11 elongate, segments 

9–11 equal in length to the 4–5 preceding combined; surface finely, densely punctate. Pronotum: strongly convex; 

lateral margin narrow, not reflexed; surface finely sparsely 

punctate-granulate. Elytra: each elytron with 10 complete 

to nearly complete striae, not appearing as rows of punctures; striae not deeply impressed, intervals weakly convex. 
Death-Watch and Spider Beetles of Wisconsin

47

Metathoracic Ventrite: not excavate for reception of the 

mesothoracic legs; anterior raised margin of the intercoxal 

process broadly arcuate to flat; posteriorly with a darkly 

pigmented, longitudinal sulcus medially, extending 

0.75X length of the disk; surface densely punctate. Legs:

not received in ventral excavations; metathoracic coxae 

grooved to receive metathoracic legs. Abdomen: with 

5 ventrites. 

Diagnosis—Euvrilletta peltata may be separated from all 

other Wisconsin Xyletininae by a combination of the following characters: terminal maxillary palpomere elongate, 

feebly triangular, length ≥2X width (Fig. 59); eyes large, 

separated by not more than 3.5X the width of the eye when 

viewed from the front; last three antennal segments equal 

in length to the preceding four or five segments combined; 

lateral pronotal margins narrow, not reflexed (extracted in 

part from White 1985, Philips 2002). As mentioned in the 

diagnosis for the previous species, specimens of E. peltata

are most easily confused with those of E. brevis.

Natural History—Euvrilletta peltata is thought to prefer 

high wood moisture content for development and may thrive 

on wood already degraded by certain fungi (Ebeling 1978). 

Damage from this species is sometimes compared to that 

of Lyctus spp. in that structural failure of wood may occur 

if the conditions are favorable (Baker 1972). Wooden joists 

and flooring in damp buildings tend to be particularly susceptible (White 1962a). In an unoccupied structure, Baker 

(1972) reported damage from re-infestation may become so 

severe that it could cause flooring to collapse. Older homes 

with crawl spaces are also heavily infested. Williams and 

Smythe (1978) estimated over 99% of 673 indoor crawl 

spaces inspected throughout 11 states in the southern United 

States were, or had been, infested with E. peltata (although 

the species identification was based on damage rather than 

on actual specimens). 

Euvrilletta peltata may develop in both sapwood and heartwood of seasoned hardwoods and softwoods (Baker 1972, 

Moore 1979) but is thought to show a distinct preference 

for certain wood species (Ebeling 1978). Moore (1964, 

1979) stated E. peltata is one of the most common species 

in southern yellow pine, although hardwoods are generally 

preferred. This is probably because southern pine timbers 

are used widely for wood-frame construction, especially in 

the South (Williams and Smythe 1978). Williams (1973) 

reported that within a barn infested with E. peltata, the yellow poplar boards were heavily infested, while the cypress 

and western pine were not. Further studies by Williams and 

Mauldin (1974) confirmed this preference for oviposition 

on yellow poplar over other wood species; they estimated 

the life cycle of E. peltata is at least two years in favorable wood species, whereas it may extend to 3–5 years in 

non-preferred wood species (Williams and Mauldin 1981). 

Within the wood, damage is usually confined to the spring 

wood of each annual ring (Baker 1972). Remediation may 

be achieved through fumigation or removal of infested 

material, especially if the infestation is localized. Extreme 

temperatures may also be an effective control method.

A complete description of the larva was provided by Böving (1954) for E. peltata (as Xyletinus peltatus) collected 

from pine wood, pine joists in a 40-year old house, and shop 

timbers of “swamp maple.” This description also included 

larvae determined as “near peltatus,” recorded from barn 

timbers, wood from a bookcase, and pine sills. In Wisconsin, but two specimens of E. peltata were seen during this 

study; one specimen was obtained at UV light and one with 

no collection information.

Phenology—Collections of adult E. peltata by Williams and 

Mauldin (1974) showed that a greater number of females 

than males were collected from the wood surface shortly 

after dusk (7–9 p.m.). Later in the evening (9–11 p.m.), both 

sexes were collected equally as this appears to be the time 

of peak mating activity. In their study, adults were collected 

18 May to 02 June, 1970, with a greater proportion of females collected later in the emergence period (Williams and 

Mauldin 1974). In Wisconsin, adult specimens of E. peltata

were collected during mid-July.

Distribution—Euvrilletta peltata is widely distributed in 

eastern North America with the greatest number of records 

from the southeastern states (Ebeling 1978). It occurs as far 

southwest as Texas, Louisiana, and Arkansas, southeast to 

Georgia and North Carolina, northeast along the east coast 

into New York, Maryland, and Massachusetts, and northwest to Pennsylvania, Kentucky, Ohio, Michigan, and Illinois (White 1982). Majka (2007a) reported this species from 

Ontario, Prince Edward Island, Quebec, and Rhode Island. 

In this study, specimens were examined from two southern 

Wisconsin counties; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 30)—The two specimens of 

E. peltata examined during this study were recorded from 

the following localities: Grant Co. (1): Wyalusing State 

Park; Richland Co. (1): No other locality data.

Genus Vrilletta LeConte

[Synonymy modified from White 1974, 1982, Philips 2002] 

Type Species: Vrilletta murrayi LeConte (designated by 

Lucas 1920: 668).

Vrilletta LeConte 1874: 64.

Pseudoxyletinus Pic 1903: 182; Pic 1912a: 45 (as subgenus).

Vrilleta LeConte; Pic 1905: 171 (lapsus calami).

Urilletta LeConte; Zoological Record 1924: 173 (lapsus 

calami).

Vriletta LeConte; Böving 1927: 57 (lapsus calami).

White (1980) re-examined this genus and described two new 

species from California: Vrilletta bicolor White and Vrilletta

pectinicornis White. In this work, he also reviewed descriptions of Vrilletta nigra Pic and Vrilletta fulvolineata Pic and 
General Technical Report FPL–GTR–209

48

suggested that V. nigra might be synonymous with Vrilletta 

convexa LeConte or V. pectinicornis and that 

V. fulvolineata might be synonymous with Vrilletta 

decorata VanDyke. Pic’s type specimens were not examined 

during White’s study because they could not be located; 

therefore, White regarded these taxa as incertae sedis until 

the types could be examined. White’s (1980) review of 

Vrilletta represents the most recent work on the genus. 

The 12 species known from North America, north of Mexico, including the two Pic species listed above, occur predominantly in the Pacific coastal states with the exception 

of Vrilletta laurentina Fall. 

Vrilletta laurentina Fall

(Figs. 39, 167, 168; Map 31)

Vrilletta laurentina Fall 1905: 195.

This species was described by Fall (1905) from two females 

collected in Toronto, Canada. Later, White (1962a) examined a series of seven females from Mt. Alto, Pennsylvania. 

Capsule Description (Figs. 39, 167, 168)—Length: 

4.6 mm. Width: 2.0 mm. Integument Color: antennae 

and palpi yellowish-orange; pronotum and elytra dark 

reddish-brown; head and ventral surface blackish; legs reddish-brown. Body Form: robust, elongate, 2.3X longer than 

wide. Vestiture: pubescence yellowish, moderately dense, 

recumbent. Head: terminal segment of each maxillary palpus elongate, distinctly pointed apically; eyes small, separated by nearly 5.1X the width of the eye when viewed from 

the front; antennae 11-segmented, segments 4–8 strongly 

serrate and distinctly wider than long; combined length of 

last 3 antennal segments longer than all preceding segments 

combined, 11th segment elongate, about 3X longer than 

wide; surface finely, densely punctate. Pronotum: with a 

narrow, smooth line medially; surface with large punctures, 

becoming larger and shallower laterally; small punctures 

moderately dense. Elytra: striae sharply impressed, intervals convex; elytral apices not truncate. Metathoracic 

Ventrite: not excavate for reception of the mesothoracic 

legs; posteriorly with a moderately shallow longitudinal 

sulcus 0.5X length of the disk; surface punctate. Legs: not 

received in ventral excavations; prothoracic and mesothoracic tibiae conspicuously concave on outer margins; 

metathoracic coxae grooved to receive metathoracic femora. 

Abdomen: with 5 ventrites.

Diagnosis—Vrilletta laurentina may be separated from all 

other Wisconsin Xyletininae by a combination of the following characters: antennal segments 4–8 strongly serrate; 

combined length of the last three antennal segments longer 

than all preceding segments combined (Fig. 39); pronotum 

with a narrow, smooth median line; elytral intervals strongly 

convex (Figs. 167, 168).

Separation of Vrilletta from other North American Ptinidae 

using Philips (2002) key may not always be obvious based 

on the couplet (#7) referring to the approximation of the 

mandibles to the metathoracic ventrite. In the specimen examined, the mandibles are not as close to the metathoracic 

ventrite as they are in other members of Xyletininae. However, when compared with specimens having the mandibles 

distant from the metathoracic ventrite, it is apparent that 

Vrilletta specimens are in fact contracted in this manner.

Natural History—Little has been published on the natural 

history of V. laurentina. White (1962a) recorded this species 

from “dead twigs and partly decayed linden branches.” The 

single Wisconsin specimen examined collected from a cantharidin bait trap was certainly an incidental recovery.

Phenology—The adult specimen of V. laurentina was recorded in Wisconsin from mid- to late April. It is possible 

that the earlier flight of this species is responsible for it being rather uncommonly collected. 

Distribution—Unlike most other members of Vrilletta, 

V. laurentina appears to occur in eastern North America 

(Fall 1905). It has been recorded from Ontario, Quebec, and 

Pennsylvania and is thought to be rather rare in collections. 

In this study, one specimen was examined from a single 

Wisconsin county; it constitutes a NEW STATE RECORD.

Wisconsin Records (Map 31)—The single specimen of V. 

laurentina examined during this study was recorded from 

the following locality: Racine Co. (1): Renak–Polak 

Maple–Beech Woods SNA.

Genus Xyletinus Latreille

[Synonymy modified from White 1982, Philips 2002] 

Type Species: Ptilinus ater Cruetzer, I.C.Z.N. 1971: 81 

(proposed by White 1969b).

Xyletinus Latreille 1809: 376.

Xylotinus Latreille; Sturm 1826: 59 (lapsus calami).

Xiletinus Latreille; Stephens 1829: 12 (lapsus calami).

Xytelinus Latreille; Griffith and Pidgeon 1832: 350 (lapsus 

calami).

Calypterus Mulsant and Godart 1859: 181 (described as 

genus but listed as subgenus of Xyletinus by Pic 1912a).

Notiomimus Wollaston 1861: 6.

Xeronthobius Morawitz 1863: 164 (listed as subgenus of 

Xyletinus by Pic 1912a).

Sternoplus Mulsant and Rey 1864: 263.

Xyletomimus Reitter 1901: 28 (as subgenus of Xyletinus).

Ryletinus Latreille; Zaitsev 1956: 76 (lapsus calami).

Xylentinus Latreille; Santoro 1957: plate (lapsus calami).

Xyletinus was described by Latreille (1809), although no 

species were included in the genus (White 1969b). One year 

later, Latreille (1810) designated Ptilinus laevis Illiger as 

the type species of Xyletinus, a species later transferred to 

Lasioderma (White 1969b). Stephens (1829) added X. ater

to Xyletinus, which White (1969b) later designated as the 

type species for the genus.
Death-Watch and Spider Beetles of Wisconsin

49

In North America, north of Mexico, Xyletinus is composed 

of 13 species, including Xyletinus puberulus Boheman, of 

uncertain status. Because a number of species previously 

placed in this genus were transferred into Euvrilletta, an 

updated list of North American Xyletinus has not yet been 

presented in existing literature. Therefore, the species considered to be found in North America (excluding Mexico) 

are as follows: 

Xyletinus bicolor White

Xyletinus californicus White 

Xyletinus carinatus White

Xyletinus confusus White

Xyletinus fasciatus White

Xyletinus fucatus LeConte

Xyletinus gracilipes Fall

Xyletinus lugubris LeConte

Xyletinus obsoletus White

Xyletinus parvus White

Xyletinus pubescens LeConte

Xyletinus rotundicollis White

Four Xyletinus species are hypothesized to occur in Wisconsin; two species have been collected to date. Xyletinus 

bicolor is included in the key as it has been recorded from 

Minnesota, as well as X. lugubris, which has been recorded 

from much of the northeastern and north-central regions of 

the United States (White 1982).

Species determinations in this genus are difficult at best. 

Specimens of X. fucatus are difficult to distinguish as they 

are determined based mostly on color (see diagnosis for 

X. fucatus). Also, separation of female X. lugubris from 

those of X. confusus or X. bicolor was not possible during 

this study as representative samples of each species were not 

obtained for examination. White (1977b) separated X. lugubris females from the other two species because it was 

said to have most antennomeres about twice as wide as 

long (compared to as wide, to a little wider than long, in 

both males and females of X. confusus and X. bicolor). Two 

females I examined fit the description for X. lugubris; however, I am hesitant to assign them to this species based on 

my examination of a male of X. lugubris. This specimen, determined by White, was easily distinguished using White’s 

(1977b) key, which stated the antennal segments of the male 

are about three times as wide as long. A number of males 

from Wisconsin express an intermediate form between 

the two character states, having most antennal segments 

about twice as wide as long, which may lead them to be 

determined to X. lugubris females, if not dissected to prove 

them to be males. The genitalia of these males more closely 

resemble those of X. confusus, to which they were assigned, 

than the similar X. bicolor. Therefore, it may be possible 

that the female specimens mentioned above are actually 

X. confusus, and that there is greater variability in the relative lengths and widths of the antennal segments than previously documented. 

Species of Xyletinus have been recorded from Populus 

tremuloides Michaux as well as “on Ceanothus americanus” 

Linnaeus (White 1982). Larvae of X. parvus have reportedly 

been collected in rabbit dung (White 1982). In Wisconsin, 

members of this genus appeared to be rather uncommonly 

collected.

Males and females are not easily separated; however, males 

tend to have the eyes larger, separated by about 4–4.5X the 

width of the eye when viewed from the front. Eyes of females are generally smaller and separated by 5–7 times the 

width of the eye when viewed from the front (White 1962b). 

For most Xyletinus, specimens may require dissection, 

which is the most accurate method of separating the sexes. 

Key to the Wisconsin Species of Adult Xyletinus

[Modified from White 1977b]

1 Body uniformly orange-brown to reddish-brown throughout (Figs. 171, 172) .........................fucatus LeConte (p. 50)

1’ Body dark brown to black...............................................................................................................................................2

2 (1’) Antennomeres 5–8 of male approximately 3X as wide as long .................................................... lugubris LeConte

2’ Antennomeres 5–8 of males <2.5X as wide as long .......................................................................................................3

3 (2’) Lateral pronotal punctures irregular with dorsal rim of each often obscure; male genitalia 

 with lateral lobes narrow and arcuate ..................................................................................................bicolor White

3’ Lateral pronotal punctures irregular and running together with posterior rim of each often 

 obscure; male genitalia with lateral lobes broader, less arcuate ................................................ confusus White (p. 50)
General Technical Report FPL–GTR–209

50

Xyletinus confusus White

(Figs. 44, 169, 170; Map 32)

Xyletinus confusus White 1977b: 528.

Capsule Description (Figs. 44, 169, 170)—Length: 2.5–

3.7 mm. Width: 1.4–1.8 mm. Integument Color: darkbrown to black; mouthparts, antennae, and legs somewhat 

lighter; elytra orange-brown to blackish. Body Form: elongate, robust, 2.0X longer than wide. Vestiture: body and 

appendages with moderately dense, short, yellowish, recumbent pubescence. Head: terminal segment of each maxillary 

palpus elongate, approximately 2.5X longer than wide; eyes 

small, separated by 4–6X the width of the eye when viewed 

from the front; antennae 11-segmented, segments 3–

10 serrate, 5–8 wider than long, segment 11 elongate; surface granulate-punctate. Pronotum: convex; slightly concave apically on each side; surface punctate, punctures laterally irregular, becoming confluent together. Elytra: humeri 

distinct, not prevalent; each elytron with 10 complete to 

nearly complete striae, not appearing as rows of punctures; 

intervals moderately convex; apex truncate. Metathoracic 

Ventrite: not excavate for reception of mesothoracic legs; 

medially with a shallow, longitudinal sulcus, running the 

length of the disk, posterior margin of sulcus with a round 

nitid patch; surface punctate. Legs: not received in ventral 

excavations; metathoracic coxae grooved to receive metathoracic legs. Abdomen: with 5 ventrites. Genitalia: lateral 

lobes mostly parallel, curving inward apically; internal 

process of median lobe with two sclerotized, wedge-shaped 

pieces. 

Diagnosis—Xyletinus confusus may be distinguished from 

all other Wisconsin Xyletininae by a combination of the following characters: body dark brown to blackish (Figs. 169, 

170); eyes small, separated by approximately four or more 

times their width when viewed from the front (e.g., Fig. 89); 

combined length of last three antennomeres shorter than all 

preceding segments combined, segments five through eight 

of males less than two and a half times as wide as long 

(Fig. 44); metathoracic ventrite not declivous anteriorly; 

male genitalia with lateral lobes mostly parallel, not strongly 

arched (extracted in part from White 1977b, Philips 2002). 

As mentioned above in the generic summary, only males of 

this species were positively identified.

Natural History—White (1982) reported X. confusus from 

Douglas-fir, Pseudotsuga menziesii (Mirbel). In Wisconsin, 

two specimens were collected at a Lindgren funnel trap, and 

one specimen was hand-collected “on exposed woody root 

at base of tree in forest” in the evening.

Phenology—Adult specimens of X. confusus were recorded 

in Wisconsin from early May to mid-June.

Distribution—Xyletinus confusus is known mostly from 

western North America, from British Columbia, Alberta, 

and the Northwest Territories in Canada, and from 

California, Wyoming, and South Dakota in the United States 

(White 1982). In this study, specimens were examined from 

three Wisconsin counties; they constitute a NEW STATE 

RECORD and new eastern range extension for the species.

Wisconsin Records (Map 32)—The four specimens of 

X. confusus examined during this study were recorded from 

the following localities: Clark Co. (2): Schmidt Maple 

Woods SNA; Dane Co. (1): No other locality data; Taylor 

Co. (1): Chequamegon National Forest–Kathryn Lake CG.

Xyletinus fucatus LeConte

(Figs. 89, 171, 172; Map 33)

Xyletinus fucatus LeConte 1865: 238.

Fall (1905) stated in his description of this species that the 

material before him was most likely composed of several 

similar species but did not separate them. White (1977b) 

confirmed this after examination of the male genitalia and 

regarded those specimens with orange-brown to reddishbrown integument as X. fucatus. However, he also noted 

that differences in male genitalia among species similar 

to X. fucatus were not always obvious and suggested that 

future work should involve numerous dissections to better 

clarify species hypothesis (White 1977b). The series before 

me is also questionable and likely composed of more than 

one species, as the color of these specimens ranges from 

light-orange to darker reddish-brown. The relatively larger 

size of the darker specimens and variation in the shape of 

the terminal maxillary palpomere also leads me to question 

their determination.

Capsule Description (Figs. 89, 171, 172)—Length: 3.0–

5.2 mm. Width: 1.5–2.4 mm. Integument Color: orangebrown to reddish-brown throughout, nearly uniform in color; elytra infrequently darker than body; elytral striae usually brownish. Body Form: elongate, robust, about 2.0X longer than wide. Vestiture: body and appendages with short, 

yellowish, moderately dense, recumbent pubescence. Head:

eyes small, separated by ≥4.0X the width of the eye when 

viewed from the front; antennomeres 3–10 serrate with the 

11th segment elongate, segments 5–7 slightly wider in the 

male than in the female; terminal segment of each maxillary 

palpus elongate to subtriangular, about 2X as long as wide; 

surface finely, densely punctate. Pronotum: as wide to 

slightly wider than base of the elytra; evenly convex; shallowly concave at sides; lateral margin sharp, explanate and 

weakly recurved; surface finely, densely punctate-granulate. 

Elytra: each elytron with 10 complete to nearly complete, 

distinctly impressed striae, intervals moderately to distinctly 

convex; slightly truncate apically. Metathoracic Ventrite:

not excavate for reception of the mesothoracic legs; intercoxal process of the mesothoracic coxae broadly arcuate, 

posteriorly with a shallow, darkly pigmented, longitudinal 

sulcus extending 0.5X the length of the disk. Legs: not received in ventral excavations; metathoracic coxae grooved 
Death-Watch and Spider Beetles of Wisconsin

51

to receive metathoracic legs; prothoracic and mesothoracic 

tibiae concave on outer surface, metathoracic tibiae flat. 

Abdomen: with 5 ventrites.

Diagnosis—Most specimens of X. fucatus may be separated 

from all other Wisconsin Xyletininae by a combination of 

the following characters: body uniformly orange-brown to 

reddish-brown throughout; eyes small, separated by approximately ≥4X their width when viewed from the front 

(Fig. 89); combined length of last three antennomeres shorter than all preceding segments combined; metathoracic ventrite not declivous anteriorly (extracted in part from White 

1977b, Philips 2002). 

The uniformly lighter color of X. fucatus generally distinguishes this species from other members of Wisconsin 

Xyletinus, although I have included in this description specimens that are considerably larger and darker reddish-brown 

than the typical X. fucatus. The reddish dorsal surface and 

uniformly colored body leads these specimens more closely 

to X. fucatus than to the other Xyletinus species, which are, 

at least in part, dark brown to blackish. White (1977b) also 

noted the difficulty in separating this species from other 

closely related species, even after examination of the male 

genitalia. Therefore, the structure of the male genitalia was 

not examined during this study for X. fucatus, but should be 

addressed in future work on Xyletinus.

Natural History—A complete larval description was provided by Böving (1954) from specimens collected in “dead 

oak twigs.” Xyletinus fucatus has also been reared from 

“dead American linden branches” (White 1982). In Wisconsin, specimens were collected using Lindgren funnel, flight 

intercept, Townes–Malaise, and cantharidin bait traps. One 

specimen was collected at a Lindgren funnel trap baited 

with ethanol, and a few were collected from flight intercept 

traps baited with cantharidin, although their uncommon 

attraction to either of these compounds is believed to be 

incidental. Regrettably, over 50% of specimens had no collection data recorded.

Phenology—Adults of X. fucatus were recorded in 

Wisconsin from early May to late August.

Distribution—Xyletinus fucatus is widely distributed in 

North America and has been recorded from British Columbia, Saskatchewan, Ontario, Quebec, and New Brunswick, 

Canada, and in the United States, from Washington and 

California, south into Texas, centrally from Illinois, Ohio, 

Michigan, and northeast to New Jersey (White 1977b, 

1982). White (1977b) reported this species from Wisconsin. During this study, specimens were recorded from eight 

counties throughout Wisconsin.

Wisconsin Records (Map 33)—The 25 specimens of 

X. fucatus examined during this study were recorded from 

the following localities: State only (6); Barron Co. 

(1): Kriska Residence; Dane Co. (8): No other label data; 

Milwaukee Co. (4): Cudahy Woods SNA; Sheridan Park; 

Racine Co. (1): Renak–Polak Maple–Beech Woods SNA; 

Sauk Co. (1): Hemlock Draw TNC; Shawano Co. (1): Jung 

Hemlock–Beech Forest SNA; Sheboygan Co. (1): Kettle 

Moraine Red Oaks SNA; Wood Co. (2): Powers Bluff 

SNA.

Genus Lasioderma Stephens

[Synonymy modified from White 1962a, 1982, Philips 

2002]

Type Species: Ptinus serricornis Fabricius 1792: 241.

Lasioderma Stephens 1835: 417. 

Pseudochina Jacquelin du Val 1860: 143 (mis-spelled as 

Pseudochinus Zoological Record 1865: 398).

Hypora Mulsant and Rey 1864: 306 (as subgenus).

Tasioderma Stephens; Chenu 1884: 214 (lapsus calami).

Lasiderma Stephens; Schilsky 1899: 30 (lapsus calami).

Ladioderma Stephens; Löding 1945: 96 (lapsus calami).

Losioderma Stephens; Borror and DeLong 1964: 

307 (lapsus calami).

Lassioderna Stephens; Mukerji 1954: 131 (lapsus calami).

Lasioderma was established by Stephens (1835) for Lasioderma testaceum Duftschmid, now considered a synonym of 

the cosmopolitan species, L. serricorne (White 1969b). Five 

species of Lasioderma are found in North America, compared to the over 50 species recognized worldwide (White 

1990, Philips 2002). Four species are more or less generally 

distributed in eastern North America, whereas Lasioderma 

haemorrhoidale (Illiger) is currently known only from California, where it is thought to have been introduced (White 

1990). To date, only L. serricorne has been recorded from 

Wisconsin, although Lasioderma semirufum Fall is included 

in the key because it is known from both Indiana and Ohio 

(White 1982). The characters used in the key for L. semirufum are taken from White (1990); specimens of this species 

were not examined during this study.

Work on Lasioderma has focused almost entirely on the 

economically important, cosmopolitan species L. serricorne, 

while surprisingly little is known about the biology of most 

other species (White 1990). Worldwide, thistles are thought 

to be the most frequent food plants of many species; they 

are also suspected to have been the original food of L. serricorne (White 1990). 

Members of Lasioderma can be distinguished from other 

North American Xyletininae by the serrate antennae with the 

last three antennal segments not elongate (Fig. 38), the lack 

of elytral striae (Figs. 173, 174), and the abrupt anterior declivity of the metathoracic ventrite with a transverse carina. 

Males and females are not readily separated, although females are thought to be larger than males (Lefkovitch 1963). 

Dissection of the genitalia or treatment of the abdomen with 

alcohol so that the abdomen becomes transparent and sexual 

structures may be observed through the cuticle (methods 

described by Papadopoulou and Buchelos (2002) for L. serricorne) are the only reliable means of separating the sexes.
General Technical Report FPL–GTR–209

52

Key to the Wisconsin Species of Adult Lasioderma

[Modified from White 1990]

1 Body bicolored, elytra darker than remainder; metathoracic ventrite with 2 transverse carinae, 

 a distinct one bordering anterior declivity, and a weaker one behind declivity which may be 

 incomplete medially..................................................................................................................................semirufum Fall

1’ Body color uniform throughout; metathoracic ventrite with a single transverse carina 

 bordering anterior declivity...............................................................................................serricorne (Fabricius) (p. 52)

apically; prothoracic and mesothoracic legs retractable into 

the declivent region of the metathoracic ventrite; metathoracic coxae grooved to receive the metathoracic legs. 

Abdomen: with 5 ventrites.

Diagnosis—Lasioderma serricorne differs from other Wisconsin Xyletininae by its serrate antennae with the last three 

segments not at all elongate (Fig. 38) and the metathoracic 

ventrite abruptly declivous anteriorly, with a single distinct 

transverse carina (extracted in part from Philips 2002).

Although diagnostic, integument color has been shown to 

vary. Coffelt and Vick (1973) noted the occurrence of a 

black body color form in a laboratory colony maintained 

for several years. While dark color forms appear rather infrequently, these variations are important to note because 

integument color is referred to taxonomically. Similar variations have been described in depth for other stored products 

Coleoptera as well, but are by no means limited to stored 

product insects (Coffelt and Vick 1973). 

Natural History—As the common name “cigarette beetle” 

or “tobacco beetle” suggests, L. serricorne is the most widespread and destructive pest of harvested and manufactured 

tobacco (Runner 1919). Damage and economic losses from 

L. serricorne infestations were estimated by the USDA 

(1971) to be 0.7% of the total warehoused tobacco commodity in 1971. Few insects actually utilize tobacco as a food 

source because of its low nutritional value and nicotine toxicity (Farnham et al. 2007). In a recent study by Farnham et 

al. (2007), the ability of L. serricorne to develop in the presence of nicotine was examined in order to determine if the 

nicotine was assimilated, sequestered, metabolized, and/or 

excreted. Their results indicated nicotine is not metabolized 

but rather excreted unmodified. Although rapid excretion 

is a mechanism utilized by some insects to rid themselves 

of toxins, L. serricorne was shown to take four days to excrete all the waste from their system, suggesting a different 

mechanism of nicotine toxicity resistance (Perry and Buckner 1959, Farnham et al. 2007). Additionally, L. serricorne

does not need external vitamins such as thiamin, pyridoxine, 

riboflavin, and nicotinic acid to develop, which may explain 

its successful growth on manufactured tobacco (Ashworth 

1993). Intracellular yeast-like endosymbionts are thought 

to produce several substances allowing it to survive without 

these otherwise important nutrients (Ashworth 1993). This 

symbiotic relationship is comparable to that seen in termites, 

Lasioderma serricorne (Fabricius)

(Figs. 38, 173, 174; Map 34)

[Synonymy modified from Pic 1912a, White 1962a, 1982, 

Español 1992]

Ptinus serricornis Fabricius 1792: 240.

Ptilinus testaceus Duftschmid 1825: 46.

Lasioderma rufescens Sturm 1826: 206.

Lasioderma testaceum Stephens 1835: 417.

Xyletinus testaceus (Duftschmid); Sturm 1837: 89.

Lasioderma castaneum Melsheimer 1846: 308.

Xyletinus breve Wollaston 1861: 15.

Pseudochina (Hypora) serricorne (Fabricius); Mulsant & 

Rey 1864: 307.

Lasioderma serricorne (Fabricius); LeConte 1865: 238.

Lasioderma testacea (Duftschmid); Kiesenwetter 1877: 150.

The species currently known as the “cigarette beetle” or “tobacco beetle” was first described by Fabricius from North 

America in 1792 as Ptinus serricornis (Runner 1919). Mulsant and Rey (1864) removed the species to Pseudochina

under the subgenus Hypora. LeConte (1965) recognized 

the species as a Lasioderma, transferring it to the genus 

where it currently resides. The name Lasioderma castaneum

frequently appears in historical literature but should be regarded as L. serricorne as it was synonomyzed by White in 

1971 (White 1971b).The numerous synonyms associated 

with this species are most likely a result of its nearly worldwide distribution. 

Capsule Description (Figs. 38, 173, 174)—Length: 1.8–

2.8 mm. Width: 1.1–1.6 mm. Integument Color: uniformly orange-brown, reddish-yellow or reddish-brown. Body 

Form: oval, moderately convex, 1.6X as long as wide. 

Vestiture: pubescence short, subrecumbent, moderately 

dense, yellowish. Head: eyes small, widely separated, not 

prominent; antennae 11-segmented, serrate, narrow, segments 4–10 similar, 11 oval and pointed, slightly longer than 

10th; surface with numerous small punctures. Pronotum:

hypomera deeply excavated ventrally; surface punctate, 

with fine, uniform, moderately dense punctures. Elytra:

not striate; surface punctate, punctures similar to those of 

pronotum. Metathoracic Ventrite: abruptly declivous anteriorly; with a single distinct transverse carina; surface finely, 

densely punctate. Legs: not received in ventral excavations; 

prothoracic tibiae distinctly widened and compressed 
Death-Watch and Spider Beetles of Wisconsin

53

which require symbiotic protozoa in order to digest 

cellulose (Pant and Fraenkel 1954).

Larvae (and less frequently adults) may also damage a variety of dried stored products in addition to tobacco, including 

seeds, grains, rice, pasta, beans, cacao, spices, dried fruits, 

vegetables, and yeast. This species also breeds in animal 

materials such as wools, silks, leather, dried insects, dried 

fish, fishmeal, meat meal, and wax (Howe 1957, White 

1990, Ashworth 1993, Blanc et al. 2006). Lasioderma serricorne has even been recorded developing on insecticides 

containing pyrethrum (Ebeling 1978). In the home, paprika 

and dog food are the most commonly infested commodity 

(Ebeling 1978).

Historically, fumigation using hydrocyanic acid gas, carbon 

disulphide, ethylene oxide, methyl bromide, or phosphine 

were used to control infestations of the tobacco beetle in 

warehouses (Runner 1919, Powell 1931). However, concerns over environmental toxicity and observed resistance to 

certain fumigants in L. serricorne populations have forced a 

re-examination of control methods (Imai and Harada 2006). 

Currently, trapping techniques with pheromone attractants 

(anhydroserricornin and serricornin) or light traps, as well 

as application of either chemical or botanical insecticides/

repellants have been used as alternatives (Levinson et al. 

1981, Hori 2004, Mahroof and Phillips 2008). Exposing tobacco to extreme heat or cold for an extended period of time 

has also been used as a non-chemical form of treatment, 

as pesticide applications for tobacco products carry heavy 

restrictions (Runner 1919, Swingle 1938, Imai and Harada 

2006). Treatment of residential infestations is generally 

through good sanitation techniques, proper storage of food 

products, and removal of infested materials. 

The absence of specimens collected outside an urban/warehouse environment is likely the result of climate conditions 

in Wisconsin. According to Powell (1931), the optimal 

temperature for development of L. serricorne is 32 °C 

(89.6 °F) and 75% humidity, while a temperature below 4–

5 °C (39.2–41 °F) for 21 consecutive days appears to be 

fatal to larvae. Lasioderma serricorne is thought to be able 

to survive at temperatures between 2 °C (35.6 °F) and 36 °C 

(96.8 °F), and all life stages may survive temperatures below 2 °C, but only for a short time (Powell 1931, Ashworth 

1993). In Wisconsin, temperatures may remain below 2 °C 

for extended periods, thereby rendering development of this 

species unlikely outside a heated structure. This is supported 

by Rees (2004): “L. serricorne is not cold hardy and survives in temperate areas only in heated buildings,” and by 

the lack of specimens obtained outside urban environments 

in Wisconsin despite the use of the synthetic pheromone, 

serricornin, in the field.

Wisconsin specimens of L. serricorne examined during this 

study were all likely collected indoors, although the exact 

location of collection was not always stated on specimen labels. Food materials listed for Wisconsin specimens include 

paprika, dried tobacco, Venezuelan cigars, and Jamaican 

ginger. A number of specimens were obtained from laboratory culture. 

Phenology—As Runner (1919) noted, the term phenology 

or seasonality is difficult to apply to this species as it is an 

indoor, stored products pest, and generations tend to vary 

depending on factors such as temperature and humidity. 

Wisconsin specimens are likely to be found indoors at all 

times of year; thus far, they have been recorded in January, 

March, July, August, September, October, November, and 

December.

Distribution—Lasioderma serricorne is distributed throughout the United States and southern Canada (Ebeling 1978). 

In this study, specimens were examined from five Wisconsin 

counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 34)—The 59 specimens of L. serricorne examined during this study were recorded from the 

following localities: State only (9): Wisc. Exp. Sta.; Dane 

Co. (31): Madison; Madison Experimental Station; Madison–Eagle Heights; Madison–Russell Laboratory; 

346 Russell Fire Cabinet (Russell Laboratory?); UW Madison Campus; No other label data; Milwaukee Co. (6): No 

other locality data; Wixon–Milwaukee Spice Corp.; Monroe 

Co. (6): Sparta; Waukesha Co. (2): Brookfield; Winnebago Co. (5): Oshkosh.

Subfamily Dorcatominae

Dorcatominae was erected by Thomson (1859) for two 

genera, Dorcatoma Herbst and Caenocara Thomson. A subsequent classification (LeConte 1878) included Byrrhodes

LeConte within this subfamily, but refrained from placing 

Petalium LeConte, Theca Mulsant and Rey (now Stagetus 

Wollaston), and Eupactus LeConte (now Calymmaderus 

Solier) in this group because of the manner whereby the 

body is contracted: mandibles not lying in as close proximity to the metathoracic ventrite as Dorcatoma, Caenocara, 

and Byrrhodes (Fall 1905). Fall (1905) chose to include the 

former three genera in his Dorcatomini, noting “the possession of metasternal and ventral pits,” which receive the 

mesothoracic and metathoracic tarsi in repose, as the most 

important character uniting the subfamily. Eight genera were 

therefore added to the Dorcatominae, three of which were 

newly described in Fall’s revision, dramatically improving 

the organization and taxonomy of the subfamily, although 

not without some hesitation. White (1966b) described a new 

genus, Cryptoramorphus, in Dorcatominae. White’s subsequent subfamilial classification closely resembled that of 

Fall (1905) until 1971 (White 1971d), when he transferred 

Mesocoelopus Jacquelin du Val, Cryptorama Fall, and 

Tricorynus Waterhouse from Dorcatominae and placed them 

in the newly erected subfamily Tricoryninae (now Mesocoelopodinae Mulsant and Rey). This division was partially 

inspired by Fall’s (1905) initial observation that the three 

genera he placed at the top of his Dorcatomini (Petalium, 

Stagetus, and Calymmaderus) constituted “an obvious interruption to an orderly sequence of genera, Lasioderma and 
General Technical Report FPL–GTR–209

54

Megorama of the Xyletinini forming a natural transition to 

Catorama and Cryptorama of the Dorcatomini.” The supportive characters Fall (1905) used were the “elongate form, 

feebly elevated disk of the prothorax, internally widened 

posterior coxal plates, and the less deeply excavated first 

ventral segment of Petalium,” characters relating them more 

closely with Anobiini than Xyletinini (Fall 1905). This suggested to White (1971d) a possible diphyletic origin of the 

genera in Fall’s Dorcatomini, encouraging the formation of 

Tricoryninae, which allowed for a more natural progression 

of development in body form (White 1971d). Classification 

used in this work follows such recent publications as Lawrence and Newton’s (1995) review of the higher taxonomy 

of Ptinidae as well as works by White (1982) and Philips 

(2002).

Members of Dorcatominae are known to utilize woody 

fungi, mushrooms, and puffballs as well as wood, dead 

branches, twigs, and vines as larval food material (White 

1982). The larvae of a number of dorcatomine species were 

described by Böving (1954) within the genera Protheca

LeConte, Petalium, Byrrhodes (as Eutylistus Fall), Dorcatoma, and Caenocara.

Currently, North American Dorcatominae contains 11 genera and 69 species north of Mexico (Philips 2002). Nine 

genera and 23 species from this subfamily are known from 

Wisconsin.

Members of North American Dorcatominae can be distinguished by a combination of the following characters: 

antennae clubbed with last three segments longer than all 

preceding (Figs. 45–57); head reflexed with mandibles near 

or attaining metathoracic ventrite when body is contracted; 

metathoracic ventrite excavate anteriorly for reception of 

mesothoracic tarsi (Figs. 80–82) (note: the grooves are often 

most easily visible on each side of the metasternal process; 

much less obvious in Striatheca White); first abdominal 

ventrite depressed or grooved to receive the metathoracic 

legs (Fig. 82, 218); body with most appendages contained 

within grooves of the ventral surface (extracted in part from 

Philips 2002).

Dorcatominae is one of the largest and taxonomically most 

difficult of the ptinid subfamilies (White 1979). Members 

of this subfamily have greatly contractile appendages; often 

specimens need to be relaxed and the head raised so the 

antennae and palpi are visible before they may be critically 

examined. Specimens of Dorcatoma and Byrrhodes require 

having the head and prothoracic ventrite elevated from the 

body to expose the form of the posterior portion of the prothoracic ventrite. However, pulling the legs away from the 

body is not necessary, and was considered by Ford (1998) 

and others to be more destructive than useful.

Key to the Wisconsin Genera of Adult Dorcatominae

[Modified from White 1971a and Philips 2002]

1 Prothoracic coxae visible ventrally when body is retracted.............................................................................................2

1’ Prothoracic coxae concealed ventrally when body is retracted ......................................................................................4

2 (1) Metathoracic ventrite produced anteriorly into a broad rounded lobe, concealing the 

 mandibles when body is retracted (Fig. 82); second abdominal ventrite subequal to 

 combined length of ventrites 3–5 (Fig. 208).....................................................................................Petalium (p. 68)

2’ Metathoracic ventrite and second abdominal ventrite not as above ...............................................................................3

3 (2’) Pubescence moderately dense, bristling; elytra with distinct, strongly impressed striae 

 throughout (Figs. 217, 218) ..............................................................................................................Stagetus (p. 75)

3’ Pubescence somewhat dense to sparse, never bristling; elytra laterally striate only or not

 striate throughout (Figs. 176, 178)...............................................................................................Calymmaderus (p. 55)

4 (1’) Eyes, incised or notched to or beyond middle when viewed from the front (Fig. 192); 

 body nearly spherical ....................................................................................................................Caenocara (p. 60)

4’ Eyes not as deeply incised; body usually broadly to narrowly oval...............................................................................5

5 (4’) Each elytron with 10 complete striae, not appearing as rows of punctures (Fig. 219)..................Striatheca (p. 76)

5 Elytra not striate as above or lacking striae .....................................................................................................................6

6 (5’) Elytra notched laterally for metathoracic legs..........................................................................................................7

6’ Elytra not notched laterally for metathoracic legs..........................................................................................................8
Death-Watch and Spider Beetles of Wisconsin

55

(Key to the Wisconsin Genera of Adult Dorcatominae continued)

7 (6) Antennae 11-segmented (Fig. 53); pubescence of elytra and pronotal disc changing in 

 direction, appearing as darker spots on the elytra (Figs. 213, 214) ....................................................Protheca (p. 74)

7’ Antennae 9-segmented (Fig. 54); pubescence of elytra and pronotal disc not or slightly 

 changing in direction, never appearing as darker spots on the elytra (Figs. 215, 216) ..................... Sculptotheca (p. 74)

8 (6’) Prothoracic ventrite produced posteriorly into 2, slender, parallel-sided processes behind 

 the prothoracic coxae and attaining or nearly attaining coxal apex (Fig. 64) (Note: this character 

 is only visible when the head and prothoracic ventrite are pulled away from the body) .............. Dorcatoma (p. 65)

8’ Prothoracic ventrite simple, produced into 2 broad, triangular processes up to 0.5X coxal length 

 (Fig. 65)................................................................................................................................................. Byrrhodes (p. 57)

Genus Calymmaderus Solier

[Synonymy modified from Pic 1912a, White 1962a, 1974, 

1982, Philips 2002] 

Type Species: Calymmaderus capucinus Solier 1849: 473 

(designated by Pic 1912b: 48). 

Calymmaderus Solier 1849: 472.

Eupactus LeConte 1861: 203.

Calymmoderus Solier; Gemminger and Harold 1869: 1785 

(lapsus calami).

Phoberus Kirsch 1873: 400 (but, see White 1974: 444).

Eutheca Kiesenwetter 1877: 155.

Lioolius Gorham 1883: 203.

Thaptor Gorham 1883: 205.

Byrrhocerus Brethes 1919: 26.

Calymaderus Solier; Pic 1923: 7 (lapsus calami).

Nevermannia Fisher 1927: 49.

Nevermannus Fisher 1927: 116.

Colymmaderus Solier; Van Dyke 1936: 178 (lapsus calami).

Thapter Gorham; Arnett 1962: 574 (lapsus calami).

Eupactidius Español 1969: 106 (as subgenus).

Calymmaderus is most diverse in the Americas, with a 

large number of species occurring from Central and South 

America (Fall 1905, White 1982, 1983b, Arnett 1983). 

Seven species, including one of uncertain status, are found 

in North America, north of Mexico, the majority of which 

are found throughout the southern-most states (White 1982, 

Arnett 1983). Two of the seven species, Calymmaderus 

obsoletus (Fall) and Calymmaderus nitidus (LeConte), have 

a more northern distribution (White 1982); both have been 

collected from Wisconsin. 

As with most Ptinidae, members of Calymmaderus appear 

to be of less economic significance in North America than in 

other parts of the world. However, one species, Calymmaderus punctulatus (LeConte), found in the south to southeastern United States has been identified as a pest in historical 

art pieces (Ramírez et al. 2005). 

Members of Calymmaderus may be easily distinguished 

from all other Wisconsin Ptinidae by the form of the 

antennae, which have the last two segments of the 

antennal club closely united (Fig. 47), by having the prothoracic coxae exposed ventrally while the body is contracted, 

and by the double third and fourth abdominal sutures.

Key to the Wisconsin Species of Adult Calymmaderus

[Modified from White 1962a]

1 Elytra laterally with two complete striae (Fig. 178); finely pubescent; surface rather dull 

 (Fig. 177)..........................................................................................................................................obsoletus (Fall)(p. 56)

1’ Elytra laterally without striae (Fig. 176); pubescence nearly obsolete; surface distinctly shining 

 (Fig. 175).....................................................................................................................................nitidus (LeConte)(p. 55)

Calymmaderus nitidus (LeConte)

(Figs. 175, 176; Map 35)

[Synonymy modified from White 1962a] 

Eupactus nitidus LeConte 1865: 236.

Calymmaderus nitidus (LeConte); Pic 1912a: 65.

Capsule Description (Figs. 175, 176)—Length: 

2.5–3.0 mm. Width: 1.3–1.7 mm. Integument Color:

dark reddish-black to black; surface shining; maxillary and 

labial palpi, antennae, and tarsi reddish-yellow to yellowish. 

Body Form: robust, oval, 1.9X longer than wide. Vestiture: pubescence yellowish, exceedingly short and sparse, 

completely recumbent. Head: 11-segmented antennae, 

clubbed, combined length of last 3 antennal segments much 

longer than all preceding segments combined, 9th antennal 

segment exceedingly large and rectangular, 10th and 11th 

segments nearly equal in size and closely united, 9th antennal segment sometimes appearing notched laterally; surface 

punctate. Pronotum: deeply excavate ventrally to receive 

the head; disk not at all raised dorsally; lateral margins 
General Technical Report FPL–GTR–209

56

rounded; surface densely punctate. Elytra: without lateral 

striae; disk slightly grooved at sides for the prothoracic and 

mesothoracic legs; surface punctate, not arranged in rows. 

Metathoracic Ventrite: excavate for reception of mesothoracic legs; anteriorly produced into an emarginate, U-shaped 

process that receives the last 2 antennal segments in repose; 

surface punctate, punctures absent to less numerous 

medially and posteriorly. Legs: received in ventral excavations; prothoracic coxae exposed ventrally during body 

retraction, narrowly separating mandibles from metathoracic 

ventrite. Abdomen: with 5 ventrites; 1st ventrite grooved 

for the metathoracic legs; ventrite 3 slightly wider than 

ventrite 4; double 3rd and 4th sutures; 5th ventrite indented 

along posterior margin.

Diagnosis—The form of the antennae (e.g., Fig. 47), absence of lateral elytral striae (Fig. 176), and exceedingly 

short pubescence will separate C. nitidus from all other Wisconsin Ptinidae. 

Natural History—Ferro et al. (2007), from Louisiana State 

University, reported collection of C. nitidus during a study 

of beetles inhabiting oak twigs. Quinn (2000) documented 

this species from beating and sweeping oaks, elms, and junipers in Texas. In Wisconsin, specimens were collected using 

Lindgren funnel traps as well as UV light. One specimen 

was “swept from vegetation on edge of small woods near 

Helena Marsh.”

Phenology—Adults of C. nitidus were recorded in Wisconsin from late June to mid-August.

Distribution—Calymmaderus nitidus is widely distributed 

in the United States, occurring from Arizona and Texas, 

southeast to Florida, northeast to Massachusetts, New Jersey, D.C., and Pennsylvania, west into Ohio, Kentucky, 

Illinois, Missouri, and Kansas (White 1982). In this study, 

specimens were examined from seven Wisconsin counties; 

they constitute a NEW STATE RECORD and new northwestern range extension of the known distribution for the 

species.

Wisconsin Records (Map 35)—The 11 specimens of 

C. nitidus examined during this study were recorded from 

the following localities: Adams Co. (1): Quincy Bluff TNC; 

Dane Co. (3): Swamp Lover’s Inc.; Fond du Lac Co. 

(1): No additional label data; Grant Co. (1): No other locality data; Iowa Co. (1): LWRSWA Helena Unit; Milwaukee 

Co. (1): Milwaukee; Richland Co. (3): No other locality 

data.

Calymmaderus obsoletus (Fall)

(Figs. 47, 177, 178; Map 36)

[Synonymy modified from White 1962a] 

Eupactus obsoletus Fall 1905: 220.

Calymmaderus obsoletus (Fall); Pic 1912a: 65.

Calymmaderus obsoletus was described by Fall (1905) 

as one of three new species having the two elytral striae 

present on the lateral margins. 

Capsule Description (Figs. 47, 177, 178)—Length: 1.9–

3.0 mm. Width: 0.9–1.3 mm. Integument Color: reddishbrown throughout; maxillary and labial palpi yellowish. 

Body Form: oval, 2.2X longer than wide. Vestiture:

pubescence yellowish, dense, slightly more so on dorsal 

surface, pubescence short, completely recumbent. Head:

antennae 11-segmented, clubbed, combined length of last 

3 antennal segments much longer than all preceding segments combined, 9th antennal segment exceedingly large 

and rectangular, 10th and 11th segments nearly equal in size 

and closely united; surface densely punctate. Pronotum:

deeply excavate ventrally to receive the head; disk not at all 

raised dorsally; with a strongly impressed sulcus anteriorly 

along the lateral margins; surface densely punctate. Elytra:

with 2 complete lateral striae; short, inner 3rd striae comprised of mainly punctures; disk faintly appearing striate 

dorsally; grooved at sides for the prothoracic, mesothoracic, 

and metathoracic legs; surface densely punctate. Metathoracic Ventrite: excavate for reception of mesothoracic legs; 

anteriorly produced into an emarginate, slightly V-shaped 

process that receives the last 2 antennal segments in repose; 

posteriorly with a short, deep excavation; surface punctate. 

Legs: received in ventral excavations; prothoracic coxae 

exposed ventrally during body retraction, narrowly separating mandibles from metathoracic ventrite. Abdomen: with 

5 ventrites; 1st ventrite grooved for the metathoracic legs; 

double 3rd and 4th sutures; ventrite 4 nearly 0.5 as wide as 

ventrites 2 or 3.

Diagnosis—The form of the antennae (Fig. 47) as well as 

the two complete lateral elytral striae (Fig. 178) separate 

C. obsoletus from all other Wisconsin Ptindae. The above 

description, however, differs somewhat from that of White 

(1962a) with respect to pubescence and form of the dorsal 

punctures. In his work, White stated the pubescence was 

short and sparse, whereas it is clearly rather dense compared 

to that of C. nitidus in the Wisconsin specimens examined. 

Additionally, White stated the punctures were exceedingly 

small, just visible on all surfaces, while punctation of the 

aforementioned specimens tended to be relatively large.

Natural History—Little has been reported of the life history 

of C. obsoletus. In Wisconsin, all specimens were collected 

using Lindgren funnel and flight intercept traps, with the 

majority obtained from the front yard of a suburban residence. Although this site provided numerous specimens of 

this species, the source of the beetles could not be identified. 

It is possible that the ptinids were emerging from a ~60-fttall dead tree located across the street in a small patch of 

preserved wetlands, although this was not confirmed. 

Phenology—Adult specimens of C. obsoletus were recorded 

in Wisconsin from early July to mid-August.

Distribution—White (1962a, 1982) reported C. obsoletus

from Texas, Louisiana, Missouri, Ohio, and Indiana. Wisconsin currently represents the northern-most extension 

of the range of this species. In this study, specimens were 

examined from two Wisconsin counties; they constitute a 
Death-Watch and Spider Beetles of Wisconsin

57

NEW STATE RECORD.

Wisconsin Records (Map 36)—The 53 specimens of C. obsoletus examined during this study were recorded from the 

following localities: Racine Co. (52): Private Property—

Arango Residence—Greenbriar Rd.; Sauk Co. (1): Spring 

Green Preserve SNA.

Genus Byrrhodes LeConte

[Synonymy modified from White 1974, 1982, Philips 2002] 

Type Species: Byrrhodes setosus LeConte 1878: 413 (by 

monotypy).

Byrrhodes LeConte 1878: 412.

Priotoma Gorham 1886: 350.

Eutylistus Fall 1905: 264.

Fachus Lucas 1920: 294.

Notiotheca Brethes 1923: 458.

Eutylistes Fall; Böving 1927: 57 (lapsus calami).

Byrrhoides LeConte; White 1966: 959 (lapsus calami).

Byrrhodes was established by LeConte (1878) for the species B. setosus. Fall (1905) retained Byrrhodes as monotypic 

but separated three species out of Dorcatoma, which lacked 

the prosternal horn-like processes, for those with the prothoracic ventrite forming two broadly, triangular processes 

(Fig. 65). Dorcatoma granus LeConte, Dorcatoma incomptus LeConte, and Dorcatoma tristriatus LeConte, 

then formed Fall’s (1905) new genus Eutylistus, along with 

Caenocara intermedius LeConte, as well as four newly 

described species. Eutylistus was distinguished from Byrrhodes based on elytral striation present in Byrrhodes and 

absent in Eutylistus (Fall 1905). White (1971a) re-examined 

the type species of Eutylistus and determined the genus to 

be a synonym of Priotoma. Subsequently, White (1971c) 

synonymized Priotoma with Byrrhodes, after concluding 

that the elytral striation described by Fall (1905) was not 

generically significant, as he found “nearly continuous intermediate conditions between the smooth elytral lines between bands of punctures to be found in Priotoma incompta

(Lec.) and P. tristriata (Lec.) and the impressed striae of 

B. setosus Lec.”

Byrrhodes consists of 12 species in North America, north of 

Mexico (White 1981, 1982, Ford 1998). Five of the 12 species were described by LeConte (1865, 1878), four by Fall 

(1905), two by White (1973, 1981), and one by Ford (1998). 

Species richness appears to be greatest in eastern North 

America, with only a few species occurring southwest into 

Texas, Arizona, and California (White 1982). Members of 

this genus are also thought to develop within fungi (Böving 

1954).

Specimens of Byrrhodes may be distinguished from all 

other Wisconsin Ptinidae by a combination of the following 

characters: clubbed antennae with last three segments much 

longer than all preceding segments (Figs. 56, 57); eyes distinctly notched, but not to or past center of eye; prothoracic 

ventrite produced posteriorly into two broadly triangular 

processes (Fig. 65); prothoracic coxae concealed ventrally 

during body retraction; head strongly deflexed with mandibles reaching the metathoracic ventrite (Figs. 180, 182, 

184); metathoracic ventrite produced anteriorly into a broad 

lobe with distinct tarsal grooves, visible in repose; elytra not 

notched at sides for metathoracic legs; appendages highly 

contractile and received in ventral excavations; first abdominal ventrite grooved for metathoracic legs (extracted in part 

from Philips 2002). Members of Byrrhodes are most easily 

confused with those of Dorcatoma, from which they may be 

readily distinguished by the form of the process on the prothoracic ventrite.

Male and female Byrrhodes may be separated by the length 

and shape of the antennal club, which is said to be enlarged 

in the male (Fall 1905, White 1962a). In all three Wisconsin 

species examined, the first segment of the antennal club is 

more produced laterally and more deeply emarginate apically in the males (Fig. 56) than in the females (Fig. 57). These 

differences are obvious in B. tristriatus and B. incomptus, 

but appear to be less so in B. intermedius. 

Key to the Wisconsin Species of Adult Byrrhodes

[Modified from White 1973]

1 Elytra with 2 distinct lateral striae, lowest lateral elytral stria deeply impressed anteriorly

 and attaining elytral fovea for mesothoracic legs (Fig. 182) ..........................................intermedius (LeConte) (p. 58)

1’ Lowest lateral elytral stria distinct only to level of metathoracic coxae or metathoracic 

 ventrite, not attaining fovea for mesothoracic legs (Figs. 180, 184) .............................................................................2

2 (1’) Upper 3rd stria nearly to just as strong as lower striae (Fig. 184).............................. tristriatus (LeConte) (p. 59)

2’ Upper 3rd stria not well-defined (Fig. 180)..................................................................... incomptus (LeConte) (p. 57)

Byrrhodes incomptus (LeConte)

(Figs. 56, 179, 180; Map 37)

[Synonymy modified from White 1962a, 1971c] 

Dorcatoma incomptum LeConte 1865: 243.

Eutylistus incomptus (LeConte); Fall 1905: 265.

Priotoma incomptus (LeConte); White 1971a: 183.

Byrrhodes incomptus (LeConte); White 1971c: 342.

Capsule Description (Figs. 56, 179, 180)—Length: 1.8–

2.4 mm. Width: 1.1–1.5 mm. Integument Color: black 
General Technical Report FPL–GTR–209

58

to reddish-brown; some with pronotum reddish-brown and 

elytra black; ventral surface reddish, sometimes clouded 

with black; maxillary and labial palpi reddish-yellow to 

yellowish; antennae yellowish to yellowish-orange; legs 

reddish; tarsi reddish to yellowish; surface shining. Body 

Form: moderately elongate, oval, 1.6X longer than wide.

Vestiture: pubescence yellowish; erect to suberect on dorsal 

surface and head, suberect to recumbent on ventral surface; 

short, slightly more dense on head and pronotum. Head: antennae 9- or 10-segmented (see diagnosis below), clubbed, 

combined length of last 3 antennal segments much longer 

than all preceding segments combined; surface shining, 

punctate. Pronotum: spherical; surface shining, densely 

punctate, punctures slightly less strongly indented than 

those of elytra. Elytra: convex; humeri prominent; punctures of elytral disk grouped and forming longitudinal rows 

separated by narrower, smooth lines (note: best seen using 

indirect lighting); lowest lateral stria distinct only to level 

of metathoracic coxae or metathoracic ventrite, not attaining fovea for mesothoracic legs; upper 3rd striae not apparent to just slightly visible, never as strong as lowest lateral 

striae; surface shining. Metathoracic Ventrite: excavate for 

reception of mesothoracic legs; with a shallow, longitudinal 

sulcus forming an elongate fovea anteriorly, constricted 

posteriorly; produced in a broadly, flat lobe anteriorly. Legs:

received in ventral excavations. Abdomen: with 5 ventrites; 

1st ventrite grooved for and nearly concealed by metathoracic legs; ventrite sutures slightly to distinctly curving upward medially.

Diagnosis—Byrrhodes incomptus may be distinguished 

from all other Wisconsin Dorcatominae by a combination 

of the following characters: eyes distinctly notched, but not 

to or past center of eye; prothoracic ventrite produced posteriorly into two broadly triangular processes (Fig. 65); prothoracic coxae concealed ventrally in repose; metathoracic 

ventrite produced anteriorly into a broad lobe with distinct 

tarsal grooves, visible in repose; lowest lateral stria distinct 

only to level of metathoracic coxae or metathoracic ventrite, 

not attaining fovea for mesothoracic legs (Fig. 180); upper 

third stria not well defined; elytra not notched at sides for 

metathoracic legs (extracted in part from White 1973, 

Philips 2002).

A single specimen collected from Wisconsin appears to have 

only 9-segmented antennae instead of the typical 10-segmented antennae. This specimen also differs from all others 

of this species in the form of the metathoracic fovea. In this 

specimen, the fovea is more deeply impressed, elongate, 

and not at all constricted posteriorly. Although the number 

of antennal segments has been known to vary within certain 

genera and species, the form of the metasternal fovea may 

potentially signify a new species or variation of B. incomptus. The color variation as described above under the diagnosis for B. tristriatus is also true of a number of specimens 

of B. incomptus seen during this survey.

Natural History—Literature to date provides no information 

as to the food requirements of this species. In Wisconsin, 

specimens were collected at flight intercept and Lindgren 

funnel traps, as well as two specimens obtained at UV light. 

One specimen was reported from the IRCW as having been 

reared from a “brown fungus,” collected on 22 November 

1998, with adult emergence occurring on 13 January 1999.

Phenology—Adult specimens of B. incomptus were recorded in Wisconsin from mid-May to late August. It is 

probable that the specimen reared from fungus described 

above emerged as a result of being brought indoors and is 

not likely an extension of its phenology. This species was 

recorded from Ohio in June and July (White 1965).

Distribution—Byrrhodes incomptus is known from much 

the northeastern United States, although it has been recorded 

from South Carolina and Florida (White 1982). It has also 

been collected north from Pennsylvania and Massachusetts, 

west to Ohio, Michigan, and Illinois (White 1982). In this 

study, specimens were examined from 12 Wisconsin counties; they constitute a NEW STATE RECORD and new 

northwestern range extension of the known distribution for 

the species.

Wisconsin Records (Map 37)—The 29 specimens of 

B. incomptus examined during this study were recorded 

from the following localities: Adams Co. (3): Quincy Bluff 

TNC; Clark Co. (1): Schmidt Maple Woods SNA; Columbia Co. (2): Rocky Run SNA; Dane Co. (4): Madison–Elver Park; Swamp Lover’s Inc.; Grant Co. (2): Wyalusing 

State Park; Iowa Co. (1): Arena Pines–Sand Barrens SNA; 

Juneau Co. (1): Lemonweir Bottomland Hardwood Forest 

SNA; Lafayette Co. (3): Wedel Property– ~3 mi. north of 

Argyle; Marinette Co. (1): Bloch Oxbow SNA; Monroe 

Co. (7): Fort McCoy SNA; Racine Co. (2): Private Property–Arango Residence–Greenbriar Rd.; Sauk Co. (2): Spring 

Green Preserve SNA.

Byrrhodes intermedius (LeConte)

(Figs. 181, 182; Map 38)

[Synonymy modified from White 1962a, 1971c] 

Caenocara intermedia LeConte 1878: 411.

Eutylistus intermedius (LeConte); Fall 1905: 265.

Priotoma intermedius (LeConte); White 1971a: 183.

Byrrhodes intermedius (LeConte); White 1971c: 342. 

Capsule Description (Figs. 181, 182)—Length: 1.6–

2.1 mm. Width: 1.1–1.3 mm. Integument Color: black; 

maxillary and labial palpi reddish-yellow to yellowish; antennae yellowish-orange; legs reddish; tarsi reddish-yellow 

to yellowish; surface shining. Body Form: spherical to 

broadly oval, 1.5X longer than wide. Vestiture: pubescence 

yellowish, erect to suberect on dorsal surface and head, 

suberect to recumbent on ventral surface, rather sparse, 

slightly more dense on head and pronotum. Head: antennae 

8-segmented, clubbed, combined length of last 3 antennal 
Death-Watch and Spider Beetles of Wisconsin

59

segments much longer than all preceding segments combined; surface shining, punctate, slightly less densely punctate than pronotum. Pronotum: spherical; surface shining, 

densely punctate, punctures slightly less strongly indented 

than those of elytra. Elytra: convex; humeri prominent; laterally with 2 distinct striae, lowest lateral elytral stria deeply 

impressed anteriorly, attaining elytral fovea for mesothoracic legs; disk punctate, punctures in irregular rows, or completely confused; surface shining. Metathoracic Ventrite:

excavate for reception of mesothoracic legs; with a shallow, 

longitudinal sulcus, obsolete posteriorly, anteriorly forming 

an elongate fovea; produced as a broad, flat lobe anteriorly; 

surface punctate. Legs: received in ventral excavations. Abdomen: with 5 ventrites; 1st ventrite grooved for, and nearly 

concealed by, metathoracic legs.

Diagnosis—Byrrhodes intermedius may be distinguished 

from all other Wisconsin Dorcatominae by a combination 

of the following characters: eyes distinctly notched, but not 

to or past center of eye; prothoracic ventrite produced posteriorly into two broadly triangular processes (Fig. 65); prothoracic coxae concealed ventrally in repose; metathoracic 

ventrite produced anteriorly into a broad lobe with distinct 

tarsal grooves, visible in repose; elytra with two distinct 

lateral striae; lowest lateral elytral stria deeply impressed 

anteriorly and attaining elytral fovea for mesothoracic legs 

(Fig. 182); elytra not notched at sides for metathoracic legs 

(extracted in part from White 1973, Philips 2002).

Natural History—Larvae of B. intermedius were described 

by Böving (1954) from specimens collected from Fomes 

fomentarius, Fomes sp., and “in fungus.” Quinn (2000) 

documented this species from beating and sweeping oaks, 

elms, and junipers in Texas. In Wisconsin, specimens were 

obtained at flight intercept and Townes–Malaise traps. 

Specimens were also collected at Lindgren funnel traps, 

including one baited with ethanol. One specimen was hand 

collected from “shelf fungus on dead Betula papyrifera.” 

Another specimen was found in the large series of D. pallicornis reared from the shelf fungus G. applanatum

(see natural history for D. pallicornis, p. 67).

Phenology—Adult specimens of B. intermedius were recorded in Wisconsin from mid-April to late August.

Distribution—Although thought to be uncommonly collected (White 1962a), B. intermedius occurs throughout eastern 

North America, from Florida, north into Massachusetts, and 

west to Ohio, Michigan, and Illinois (Böving 1954, White 

1982). Majka (2007a) recorded this species from Nova 

Scotia and Quebec. In this study, specimens were examined 

from seven Wisconsin counties; they constitute a NEW 

STATE RECORD.

Wisconsin Records (Map 38)—The 15 specimens of 

B. intermedius examined during this study were recorded 

from the following localities: Adams Co. (1): Quincy Bluff 

TNC; Buffalo Co. (1): Engel Farm Property; Dane Co. 

(3): Private Property–Madison–501 Hammersley Dr.; 

Swamp Lover’s Inc.; Jackson Co. (1): No additional label 

data; Milwaukee Co. (6): Cudahy Woods SNA; Sauk Co. 

(1): Hemlock Draw TNC; Shawano Co. (2): Jung Hemlock–Beech Forest SNA. 

Byrrhodes tristriatus (LeConte)

(Figs. 57, 183, 184; Map 39)

[Synonymy modified from White 1962a, 1971c] 

Dorcatoma tristriatum LeConte 1878: 411.

Eutylistus tristriatus (LeConte); Fall 1905: 266.

Priotoma tristriatus (LeConte); White 1971a: 183.

Byrrhodes tristriatus (LeConte); White 1971c: 342.

Byrrhodes tristiatus (LeConte); White 1982: 27 (lapsus 

calami).

Capsule Description (Figs. 57, 183, 184)—Length: 1.8–

2.4 mm. Width: 1.2–1.5 mm. Integument Color: black to 

reddish-brown; some with pronotum reddish-brown and elytra black; ventral surface reddish, sometimes clouded with 

black; maxillary and labial palpi reddish-yellow to yellowish; antennae yellowish to yellowish-orange; legs reddish; 

tarsi reddish to yellowish; surface shining. Body Form:

robust, broadly oval, 1.6X longer than wide. Vestiture: pubescence yellowish to grayish, erect to suberect on dorsal 

surface and head, suberect to recumbent on ventral surface, 

short, slightly more dense on head and pronotum. Head:

antennae 10-segmented, clubbed, combined length of last 

3 antennal segments much longer than all preceding segments combined; surface shining, punctate. Pronotum:

spherical; surface shining, densely punctate, punctures 

slightly less strongly indented than those of elytra. Elytra: convex; humeri prominent; punctures of elytral disk 

grouped and forming longitudinal rows separated by narrower, smooth lines (note: best seen using indirect or filtered 

lighting); lowest lateral stria distinct only to level of metathoracic coxae or metathoracic ventrite, not attaining fovea 

for mesothoracic legs; upper 3rd stria nearly or just as strong 

as lower stria; surface shining. Metathoracic Ventrite:

excavate for reception of mesothoracic legs; with a shallow, 

longitudinal sulcus forming an elongate fovea anteriorly; 

produced in a broadly, flat lobe anteriorly. Legs: received in 

ventral excavations. Abdomen: with 5 ventrites; 1st ventrite 

grooved for, and nearly concealed by, metathoracic legs; 

ventrite sutures distinctly curving upward medially.

Diagnosis—Byrrhodes tristriatus may be distinguished 

from all other Wisconsin Dorcatominae by a combination 

of the following characters: eyes distinctly notched, but not 

to or past center of eye; prothoracic ventrite produced posteriorly into two broadly triangular processes (Fig. 65); prothoracic coxae concealed ventrally in repose; metathoracic 

ventrite produced anteriorly into a broad lobe with distinct 

tarsal grooves, visible in repose; lowest lateral stria distinct 

only to level of metathoracic coxae or metathoracic ventrite, 

not attaining fovea for mesothoracic legs; upper third stria 
General Technical Report FPL–GTR–209

60

nearly to just as strong as lower stria (Fig. 184); elytra not 

notched at sides for metathoracic legs (extracted in part 

from White 1973, Philips 2002).

The highly contractile nature of Byrrhodes makes counting 

the number of antennal segments difficult. In B. tristriatus, 

the segments of the antennal funicle are so tightly compacted that it is difficult to determine if the antennae are 10- or 

11-segmented. Also, the color variation observed within 

the current set of specimens is aberrant from what has been 

described for this species. It is likely that the lighter reddishbrown specimens are teneral; however, the specimen with 

a reddish pronotum and black elytra may represent a new 

color variation of B. tristriatus. 

Natural History—Byrrhodes tristriatus has been recorded 

from Polyporus cuticularis Bulliard (Weiss and West 1922, 

White 1982). In Wisconsin, specimens were collected at 

flight intercept, Lindgren funnel, and Townes–Malaise traps, 

many of these from a single location in an oak savanna next 

to a sandy prairie. 

Phenology—Adult specimens of B. tristriatus were recorded in Wisconsin from early June to mid-August.

Distribution—Byrrhodes tristriatus has been recorded from 

Texas, Louisiana, Mississippi, Georgia, and Florida, north 

into Pennsylvania, Massachusetts, and Maryland (White 

1982). In this study, specimens were examined from eight 

Wisconsin counties; they constitute a NEW STATE RECORD and new northwestern range extension of the known 

distribution for the species.

Wisconsin Records (Map 39)—The 16 specimens of 

B. tristriatus examined during this study were recorded 

from the following localities: Adams Co. (1): Quincy Bluff 

TNC; Dane Co. (2): Swamp Lover’s Inc.; Grant Co. 

(2): Blue River Sand Barrens SNA; Juneau Co. (1): Lemonweir Bottomland Hardwood Forest SNA; Lafayette Co. 

(1): Wedel Property– ~3 mi. north of Argyle; Monroe Co. 

(6): Fort McCoy SNA; Sheboygan Co. (1): Kettle Moraine 

Red Oaks SNA; Wood Co. (2): Griffith St. Nursery. 

Genus Caenocara Thomson

[Synonymy modified from Pic 1912a, White 1974, 1982, 

Philips 2002] 

Type Species: Dorcatoma bovistae Hoffmann 1803: 100 

(by original designation and monotypy).

Caenocara Thomson 1859: 90.

Tylistus LeConte 1861: 203.

Enneatoma Mulsant and Rey 1864: 328.

Coenocara Thomson; LeConte 1865: 242 (lapsus calami).

Cyphanobium Broun 1893: 1149.

Caenocara consists of 14 species in North America, north 

of Mexico, including one of uncertain status (White 1982, 

Philips 2002). Five of these species have been collected in 

Wisconsin. According to White (1962a), “most if not all 

members of this genus pass the larval stage in puffballs 

(Lycoperdon).” Adult specimens have also been recorded 

from “beating oak foliage” (Fall 1905). It may be interesting to note that a large majority of specimens collected from 

Wisconsin were obtained at Townes–Malaise traps as opposed to Lindgren funnel or flight intercept traps.

Members of Caenocara most closely resemble those of 

Byrrhodes and Dorcatoma, from which they may be easily 

distinguished by the deeply emarginate to nearly divided 

compound eyes. Species identifications, however, are questionable at best. In fact, White (1962a) stated, “In most 

cases determination to species is only possible if the specimen is relaxed and head raised so that antennae and palpi 

are visible; even with this done, determinations are often 

doubtful.” 

Caenocara is in need of taxonomic attention as it has not 

been adequately revised since Fall (1905). The form and 

size of the maxillary palpi, antennae, and distance between 

the eyes are relied on heavily in previous keys. In some 

specimens, characters utilized in differentiating species appear to be clear and discontinuous, while in others any distinctions are subtle, at best. For example, both C. inepta and 

C. oculata are said to have the terminal maxillary palpomere 

1.3X longer than wide or less; however, in many specimens 

examined, this measurement was not found to be constant. 

This may be at least partially due to the insect drying and 

the palpus curling slightly, making exact measurement difficult. Also, because these insects are so small, the angle 

at which the specimen is held while measuring will cause 

some inconsistency. Therefore, the shape of the maxillary 

palpus is given greater consideration in specific determinations rather than its relative length and width, although these 

measurements were found to be useful in other species, such 

as C. tenuipalpa and to a lesser extent, C. blanchardi. Difficulties in determinations are elaborated on further in the 

species capsule descriptions that follow. 

Male and female Caenocara may be separated by the form 

of the first segment of the antennal club (Fall 1905), which 

is more strongly produced laterally in the males (Fig. 50) 

and forming a transverse isosceles triangle in the females 

(Fig. 51) (Fall 1905). The eyes also tend to be larger and 

less deeply emarginate in the males than females, although 

this is not true for all Caenocara species (Fall 1905). Species identification in both Fall’s (1905) and White’s (1962a) 

keys rely on sexual dimorphism for species determinations, 

making identification of a female specimen alone impossible 

when not collected with a male. In certain species, identification of females was possible using other characters; in the 

cases of both C. inepta and C. oculata, many females were 

left undetermined unless they were part of a collecting event 

including males. 

Caenocara sycmnoides LeConte, although thought to be 

relatively uncommon, is included in the key as it has been 

found widely across the northern United States (White 

1962a).
Death-Watch and Spider Beetles of Wisconsin

61

Key to the Wisconsin Species of Adult Caenocara

[Modified from Fall 1905 and White 1962a]

1 Elytral pubescence relatively short, much inclined and nearly uniform in direction; 

 antennal club in male blackish, paler in female................................................................................ sycmnoides LeConte

1’ Elytral pubescence long, erect, and alternating in direction; antennae pale in both sexes ...............................................2

2 (1’) Terminal maxillary palpomere narrow, subparallel, 2.5–3X longer than wide (Fig. 63); 

 terminal antennal segment not arched; eyes cleft, emargination equal to 0.5 diameter in 

 male, nearly divided in female.................................................................................................tenuipalpa Fall (p. 64)

2’ Terminal maxillary palpomere wider, usually <2X longer than wide; terminal antennal 

 segment and eyes variable ...............................................................................................................................................3

3 (2’) Terminal antennal segment in male slightly arched with the tip acutely pointed (Fig. 48); 

 eyes of male larger than those of female, area between eyes equal to or narrower than the 

 vertical diameter of the eye (♂♂); eye cleft, emargination equal to 0.5 diameter in male, 

 nearly divided in female head and pronotum red to reddish brown .................................... bicolor (Germar) (p. 61)

3’ Terminal antennal segment without acutely pointed tip; eyes and color variable ............................................................4

4 (3’) Terminal maxillary palpomere less broadly triangular, apex obliquely truncate 

 (Fig. 61)................................................................................................................................... blanchardi Fall (p. 62)

4’ Terminal maxillary palpomere broadly triangular, apex squarely truncate ......................................................................5

5 (4’) Eyes of male distinctly larger than those of female, area between nearly equal to or 

 narrower than the vertical diameter of the eye in male, 1.3–2X wider than the vertical 

 diameter of eye in female; eyes cleft, emargination equal to 0.75 diameter in male, nearly 

 divided in female............................................................................................................................. inepta Fall (p. 63)

5’ Eyes of male slightly larger than those of female, area between wider, nearly 1.3–2X wider 

 than the vertical diameter of the eye, eyes nearly divided in both sexes..........................................oculata (Say) (p. 64)

Caenocara bicolor (Germar)

(Figs. 48, 185, 186; Map 40)

[Synonymy modified from White 1962a] 

Dorcatoma bicolor Germar 1824: 79.

Caenocara bicolor (Germar); Fall 1905: 275.

Capsule Description (Figs. 48, 185, 186)—Length: 

1.8 mm. Width: 1.3 mm. Integument Color: reddishbrown throughout; maxillary and labial palpi, antennae, 

and tarsi yellowish-orange. Body Form: spherical, 

1.4X longer than wide. Vestiture: pubescence yellowish, 

erect to suberect, sparse, alternating in direction. Head: 

terminal maxillary palpomere narrowly truncate, nearly 

2.1X longer than wide; eyes large, cleft, emargination equal 

to 0.5 the diameter of the eye, eyes separated in front by a 

little less than their vertical diameter (♂♂); antennae 9-segmented, clubbed, 7th segment transversely triangular (♂♂), 

9th segment slightly curved and distinctly pointed apically, 

combined length of last 3 antennal segments much longer 

than preceding segments combined; surface shining, punctate. Pronotum: convex; wider at base, curving posteriorly 

at center towards scutellum, constricted apically; surface 

shining, punctate. Elytra: humeri prominent; with 2 complete lateral striae from base to apex, shorter 3rd upper 

striae terminating before level of metathoracic legs; surface 

shining, punctate. Metathoracic Ventrite: excavate for 

reception of mesothoracic legs; anteriorly produced in a 

flat, T-shaped lobe; posteriorly with a slightly raised, darkly 

pigmented, longitudinal carina, terminating anteriorly in an 

oval-shaped puncture; surface punctate, with large punctures. Legs: received in ventral excavations. Abdomen:

with 5 ventrites; 1st ventrite grooved for and nearly concealed by metathoracic legs; 5th ventrite nearly 1.5X longer 

than ventrites 3 and 4 combined.

Diagnosis—Caenocara bicolor may be separated from all 

other Wisconsin Ptinidae by a combination of the following 

characters: eyes deeply emarginate; eyes of male larger than 

those of female, separated in front by a distance less than 

the longest vertical diameter of the eye; terminal antennal 

segment of male curved and pointed at tip (said to be curved 

and somewhat pointed in female (White 1962a)) (Fig. 48); 

prothoracic coxae concealed ventrally in repose; elytral pubescence long and erect; pronotum and head red to reddishbrown; body with mandibles reaching the metathoracic 

ventrite (extracted in part from White 1962a, Philips 2002). 
General Technical Report FPL–GTR–209

62

The black elytra contrasting with the red head and pronotum 

are thought to be diagnostic for this species and were noted 

to differ very little between specimens according to Fall 

(1905). However, the Wisconsin specimens examined clearly exhibit the typical reddish-brown head and pronotum, yet 

the elytra are not any darker than the pronotum. It is possible that these specimens represent a variation of the color 

seen in C. bicolor, or that they are simply teneral adults. 

Natural History—In Wisconsin, only two male specimens 

were examined during the present study; one reported from 

a Townes–Malaise trap and the other using an unknown 

method. The former specimen was taken from a trap sample 

containing mostly C. oculata specimens.

Phenology—The only adult specimen of C. bicolor with 

a date recorded was found in Wisconsin during an early to 

mid-August sampling interval.

Distribution—Caenocara bicolor has been recorded from 

much of the central and eastern United States, northeast 

from Massachusetts and Michigan, southeast into Virginia 

and Kentucky, and west to Nebraska, Kansas, and Texas 

(White 1982). In this study, specimens were examined from 

two Wisconsin counties; they constitute a NEW STATE 

RECORD and new northwestern range extension of the 

known distribution for the species.

Wisconsin Records (Map 40)—The two specimens of 

C. bicolor examined during this study were recorded from 

the following localities: Milwaukee Co. (1): Milwaukee; 

Dane Co. (1): Swamp Lover’s Inc.

Caenocara blanchardi Fall

(Figs. 49, 61, 187, 188; Map 41) 

Caenocara blanchardi Fall 1905: 273.

Fall (1905) described C. blanchardi from a series of five 

specimens taken in Massachusetts by Blanchard, for whom 

the species was dedicated.

Capsule Description (Figs. 49, 61, 187, 188)—Length: 

1.6–2.2 mm. Width: 1.2–1.6 mm. Integument Color:

reddish-black to black; maxillary and labial palpi, antennae, and tarsi yellowish to yellowish-orange; head reddish; 

pronotum red, reddish-black, or black; elytra reddish-black 

to black; ventral surface blackish; legs reddish-black. Body 

Form: spherical, 1.3X longer than wide. Vestiture: pubescence yellowish, erect to suberect, sparse, alternating 

in direction. Head: terminal maxillary palpomere oblique, 

1.5–2.0X longer than wide; eyes nearly divided and separated by nearly 1.5X their vertical diameter (♀♀); antennae 

9-segmented, clubbed, 7th segment broadly triangular (♀♀), 

9th segment slightly curved, apically rounded, combined 

length of last 3 antennal segments much longer than preceding segments combined; surface shining, punctate. Pronotum: convex; wider at base, curving posteriorly at center 

towards scutellum, constricted apically; surface shining, 

punctate. Elytra: humeri prominent; with 2 complete lateral 

striae from base to apex, shorter 3rd upper stria terminating 

before level of metathoracic legs; surface shining, punctate. 

Metathoracic Ventrite: excavate for reception of mesothoracic legs; anteriorly produced in a flat, T-shaped lobe, 

shallowly grooved along outer margin; posteriorly with a 

slight to indiscernible longitudinal depression, oval-shaped 

puncture barely evident; surface shining, punctate, with 

large punctures. Legs: received in ventral excavations. Abdomen: with 5 ventrites; 1st ventrite grooved for and nearly 

concealed by metathoracic legs; 5th ventrite nearly 

1.5X longer than combined length of ventrites 3 and 4.

Diagnosis—Caenocara blanchardi may be separated from 

all other Wisconsin Ptinidae by a combination of the following characters: terminal maxillary palpomere strongly 

oblique laterally (Fig. 61); eyes deeply emarginate, those of 

male subequal in size to those of female; terminal antennal 

segment only slightly curved, tip somewhat pointed 

(Fig. 49); prothoracic coxae concealed ventrally in repose; 

elytral pubescence long and erect; body with mandibles 

reaching the metathoracic ventrite (Figs. 187, 188) 

(extracted in part from White 1962a, Philips 2002).

Wisconsin specimens of C. blanchardi may be separated 

with some trepidation from those of C. tenuipalpa by having the terminal maxillary palpomere distinctly wider at 

the apex than at the base of the segment. This character is 

unfortunately comparative in nature and requires examination of specimens of both species in order to make accurate 

comparisons. However, the relative lengths and widths of 

this segment do seem to be useful, although the specimens 

examined during this survey differ slightly from that 

reported by Fall (1905). In his description, Fall stated the 

terminal maxillary palpomere is 0.5X longer than wide in 

C. blanchardi, compared to 2.5X longer than wide in 

C. tenuipalpa. In the Wisconsin specimens examined during 

this survey, the terminal maxillary palpomere is 1.5–

2X longer than wide in C. blanchardi and 2.5–3X longer 

than wide in C. tenuipalpa. In addition, the color of Wisconsin C. blanchardi specimens differs from previous descriptions. White (1962a) stated specimens of C. blanchardi are 

completely black, a character utilized in his key to species. 

However, specimens identified by him from the OSUC as 

well as specimens collected from Wisconsin, are distinctly 

reddish-black to black. 

Natural History—In Wisconsin, only female specimens of 

C. blanchardi were collected: two from a flight intercept 

trap, two from a Townes–Malaise trap, and one at a “backyard barrier trap.” The majority of specimens were found 

crawling on the outer surface of a giant puffball mushroom 

growing on the grassy path of a dry prairie. It was at this 

location I experienced the defense mechanism commonly 

used by other species in this genus (notably C. oculata; 

Weiss 1922). Their nearly perfectly cylindrical body shape 

and their ability to fold all appendages within grooves of the 
Death-Watch and Spider Beetles of Wisconsin

63

ventral surface allows them to quickly retract and drop to 

the ground when disturbed, making it exceedingly difficult 

to find them again. 

Phenology—Adult specimens of C. blanchardi were 

recorded in Wisconsin from mid-April to mid-September, 

although no specimens were collected during the months 

of June or July.

Distribution—Caenocara blanchardi has been recorded 

from Oregon, Michigan, Ohio, and Massachusetts (White 

1982). In this study, specimens were examined from four 

Wisconsin counties; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 41)—The 11 specimens of 

C. blanchardi examined during this study were recorded 

from the following localities: Dane Co. (1): Madison; 

Green Co. (6): Muralt Bluff Prairie SNA; Oneida Co. 

(2): No other label data; Rock Co. (2): Private Property–

1.7 mi. NW Janesville. 

Caenocara inepta Fall

(Figs. 189, 190; Map 42)

Caenocara inepta Fall 1905: 276.

Capsule Description (Figs. 189, 190)—Length: 1.9–2.4 

mm. Width: 1.5–1.7 mm. Integument Color: dark reddishbrown to black; maxillary and labial palpi, antennae, and 

tarsi yellowish to yellowish-orange. Body Form: spherical, 

1.4X longer than wide. Vestiture: pubescence yellowish, 

erect to suberect, sparse, alternating in direction. Head: terminal maxillary palpomere broadly triangular, apically truncate, nearly 1.3X longer than wide; eyes cleft, emargination 

equal to 0.5–0.75 the diameter of the eye (♂♂), to nearly 

divided (♀♀); each eye separated in front by a little less or 

equal to its vertical diameter (♂♂) to 1.3–2X its vertical 

diameter (♀♀); antennae 9-segmented, clubbed, 7th segment transversely triangular (♂♂) to triangular (♀♀), 9th 

segment curved, apically rounded, combined length of last 

3 antennal segments much longer than preceding segments 

combined; surface somewhat shining, punctate. Pronotum:

convex; wider at base, curving posteriorly at center towards 

scutellum, constricted apically; surface shining, punctate.

Elytra: humeri prominent; with 

2 complete lateral striae from base to apex, shorter 3rd upper striae terminating before level of metathoracic legs; surface somewhat shining, punctate. Metathoracic Ventrite:

excavate for reception of mesothoracic legs; anteriorly produced in a flat, T-shaped lobe, grooved along outer margin; 

posteriorly without or with a less distinct, darkly pigmented, 

longitudinal depression, terminating anteriorly in an ovalshaped puncture; surface punctate, with large punctures. 

Legs: received in ventral excavations. Abdomen: with 5 

ventrites; 1st ventrite grooved for and nearly concealed by 

metathoracic legs; 5th ventrite nearly 1.5X longer than 

ventrites 3 and 4 combined. 

Diagnosis—Caenocara inepta may be separated from all 

other Wisconsin Ptinidae by a combination of the following 

characters: terminal maxillary palpomere broadly triangular, apically truncate; eyes deeply emarginate; eyes of male 

larger than those of female, separated in front by a distance 

equal to the longest vertical diameter of the eye; terminal antennal segment with rounded tip; prothoracic coxae 

concealed ventrally in repose; elytral pubescence long and 

erect; body with mandibles reaching the metathoracic ventrite (Figs. 189, 190) (extracted in part from White 1962a, 

Philips 2002).

Caenocara inepta so closely resembles Caenocara oculata

(Say) that they may only be separated by the sexually dimorphic eyes. Males of C. inepta have the eyes much larger 

than those of females, whereas in C. oculata, the eyes of 

males and females are similar in size. For this reason, 

C. inepta females may not be determined unless they are 

within a larger series containing male specimens. 

Some male specimens of C. inepta examined during this 

study have the eyes separated by slightly more than the vertical diameter of the eye, thus possibly causing them to be 

determined as Caenocara similis (Say) according to Fall’s 

(1905) key. However, because many of these specimens are 

contained in a larger series of specimens that are distinctly 

C. inepta, it is unlikely that this slight difference in width 

between the eyes is significant in the specimens collected.

Natural History—Although this species is thought to be 

uncommon, a relatively large number of specimens were recorded from Wisconsin, many of which were obtained during different collecting years at the Spring Green Preserve. 

Interestingly, the majority of C. inepta specimens collected 

were males, even within large series, with the exception of 

a series of adults reared from fungus in which seven of the 

eight specimens were females. Other Wisconsin specimens 

were collected at Townes–Malaise, flight intercept, and 

Lindgren funnel traps. Two specimens were collected in a 

“human dung/malt/molasses” baited pitfall trap. 

Phenology—Adults of C. inepta were recorded in 

Wisconsin from early June to mid-October.

Distribution—Caenocara inepta has been recorded from 

New Jersey, Tennessee, Florida, and Texas (White 1982). 

In this study, specimens were examined from six Wisconsin 

counties; they constitute a NEW STATE RECORD and

new northwestern range extension of the known distribution 

for the species.

Wisconsin Records (Map 42)—The 122 specimens of 

C. inepta examined during this study were recorded from 

the following localities: Columbia Co. (2): Rocky Run 

SNA; Iowa Co. (8): No additional label data; Monroe Co. 

(1): Fort McCoy SNA; Sauk Co. (101): Spring Green Preserve SNA; Waukesha Co. (9): Kettle Moraine Southern 

Unit; Wood Co. (1): Powers Bluff SNA.
General Technical Report FPL–GTR–209

64

Caenocara oculata (Say)

(Figs. 50, 51, 62, 191, 192; Map 43)

[Synonymy modified from White 1962a] 

Dorcatoma oculata Say 1824: 273.

Caenocara oculata (Say); LeConte 1865: 243.

Capsule Description (Figs. 50, 51, 62, 191, 192)—Length: 

1.8–2.1 mm. Width: 1.3–1.4 mm. Integument Color:

mostly black; humeri, legs, and head (in part) reddish; pronotum black to reddish; maxillary and labial palpi, antennae, and tarsi yellowish to yellowish-orange. Body Form:

spherical, 1.3X longer than wide. Vestiture: pubescence 

yellowish, erect to suberect, sparse, alternating in direction. 

Head: terminal maxillary palpomere broadly triangular, 

apically truncate, nearly 1.3X longer than wide; eyes nearly 

divided and separated by 1.3–2X their vertical diameter in 

both sexes; antennae 9-segmented, clubbed, 7th segment 

transversely triangular (♂♂) to triangular (♀♀), 9th segment 

curved, apically rounded, combined length of last 3 antennal 

segments much longer than preceding segments combined; 

surface shining, punctate. Pronotum: convex; widest basally, curving posteriorly at center towards scutellum, constricted apically; surface shining, punctate. Elytra: humeri 

prominent; with 2 complete lateral elytral striae from base 

to apex, shorter 3rd upper striae terminating before level of 

metathoracic legs; surface shining, punctate. Metathoracic 

Ventrite: excavate for reception of mesothoracic legs; anteriorly produced in a flat, T-shaped lobe, grooved along outer 

margin; posteriorly with a slight longitudinal depression, 

terminating anteriorly in an oval-shaped puncture; surface 

punctate, with large punctures. Legs: received in ventral excavations. Abdomen: with 5 ventrites; 1st ventrite grooved 

for and nearly concealed by metathoracic legs; 5th ventrite 

nearly 1.5X longer than ventrites 3 and 4 combined. 

Diagnosis—Caenocara oculata may be separated from all 

other Wisconsin Ptinidae by a combination of the following 

characters: terminal maxillary palpomere broadly triangular, 

apically truncate (Fig. 62); eyes deeply emarginate; eyes 

of male subequal in size to those of female, separated in 

front by a distance 1.3–2X the vertical diameter of the eye; 

terminal antennal segment with rounded tip (Figs. 50, 51); 

prothoracic coxae concealed ventrally in repose; elytral 

pubescence long and erect; body with mandibles reaching 

the metathoracic ventrite (Figs. 191, 192) (extracted in part 

from White 1962a, Philips 2002). As mentioned previously 

in the diagnosis for C. inepta, females of C. oculata were 

not determined unless contained within a series including 

males.

Males are not always easily separated from females because 

they may have the seventh antennal segment strongly to 

slightly produced laterally, which nearly approaches the 

condition observed in females (Figs. 50, 51).

Natural History—Caenocara oculata, commonly known 

as the puffball beetle, has been recorded from puffball 

mushrooms in the genera Lycoperdon and Scleroderma

(Weiss 1922). Larvae of this species were described by 

Böving (1954) from specimens all reported from puffballs. 

Weiss (1922) described in detail the larval, pupal, and adult 

stages of this species and its life history within puffballs. In 

this work, he noted what was observed in Wisconsin: when 

disturbed, C. blanchardi adults immediately fold in the appendages and fall off the surface of the mushroom. In Wisconsin, specimens were collected using Townes–Malaise, 

flight intercept, and Lindgren funnel traps.

Phenology—Adult specimens of C. oculata were recorded 

in Wisconsin from mid-April to late August.

Distribution—Caenocara oculata is said to be the most 

widely distributed species in this genus (White 1962a) and 

has been recorded from Vermont, Maine, and New Hampshire, south to North Carolina, southwest into Louisiana, 

Texas, and Arizona, and north from Kansas and Missouri, 

into Wisconsin and Michigan (White 1982). During this 

study, specimens were recorded from 15 Wisconsin 

counties.

Wisconsin Records (Map 43)—The 82 specimens of 

C. oculata examined during this study were recorded from 

the following localities: State only (4); Columbia Co. 

(1): Rocky Run SNA; Dane Co. (31): Madison; Swamp 

Lover’s Inc.; Dodge Co. (2): Beaver Dam; Fond du Lac 

Co. (1): No other locality data; Grant Co. (11): Wyalusing 

State Park; No additional locality data; Iowa Co. (2): No 

additional label data; Jackson Co. (18): No additional locality data; Oneida Co. (1): No additional label data; Racine 

Co. (3): Renak–Polak Maple–Beech Woods SNA; Richland 

Co. (1): LWRSWA Lone Rock Unit; Rock Co. (2): Private 

Property—1.7 mi. NW Janesville; No additional label data; 

Sauk Co. (1): Spring Green Preserve SNA; Shawano Co. 

(2): 1.3 mi. NE Wittenberg; Jung Hemlock–Beech Forest 

SNA; Walworth Co. (1): Kettle Moraine Oak Opening 

SNA; Waukesha Co. (1): Kettle Moraine Southern Unit.

Caenocara tenuipalpa Fall

(Figs. 52, 63, 193, 194; Map 44)

Caenocara tenuipalpa Fall 1905: 275.

Capsule Description (Figs. 52, 63, 193, 194)—Length: 

1.5–1.8 mm. Width: 1.1–1.5 mm. Integument Color: dark 

reddish-brown to black; maxillary and labial palpi, antennae, and tarsi yellowish to yellowish-orange. Body Form:

spherical, 1.3X longer than wide. Vestiture: pubescence 

yellowish, erect to suberect, sparse, alternating in direction. Head: terminal maxillary palpomere elongate, narrow, 

2.5–3X longer than wide; eyes cleft, emargination equal to 

0.5 its length (♂♂) to nearly divided (♀♀), eyes separated 

in front by a little less than their vertical diameter (♂♂) to 

distinctly more than their vertical diameter (♀♀); antennae 

9-segmented, clubbed, 7th segment transversely triangular 

(♂♂) to triangular (♀♀), 9th segment not at all curved, 
Death-Watch and Spider Beetles of Wisconsin

65

similar in form in both sexes, slightly longer than wide in 

males, combined length of last 3 antennal segments much 

longer than preceding segments combined; surface shining, 

punctate. Pronotum: convex; wider at base, curving posteriorly at center towards scutellum, constricted apically; surface shining, punctate. Elytra: humeri prominent; with 

2 complete lateral striae from base to apex, shorter 3rd 

upper stria terminating before level of metathoracic legs; 

surface shining, punctate. Metathoracic Ventrite: excavate 

for reception of mesothoracic legs; anteriorly produced in a 

flat, T-shaped lobe, shallowly grooved along outer margin; 

posteriorly with slightly pigmented, shallow, longitudinal 

depression, terminating anteriorly in a round to oval-shaped 

puncture; surface punctate, with large punctures. Legs: received in ventral excavations. Abdomen: with 5 ventrites; 

1st ventrite grooved for and nearly concealed by metathoracic legs; 5th ventrite nearly 1.5X longer than ventrites 

3 and 4 combined.

Diagnosis—Caenocara tenuipalpa may be separated from 

all other Wisconsin Ptinidae by a combination of the following characters: terminal maxillary palpomere slender, 

subparallel, nearly 2.5X as long as wide (Fig. 63); eyes 

deeply emarginate; eyes of male larger than those of female, 

separated in front by a distance less than the longest vertical 

diameter of the eye; terminal antennal segment not curved, 

similar in form in males as in females (Fig. 52); prothoracic 

coxae concealed ventrally in repose; elytral pubescence 

long and erect; body with mandibles reaching the metathoracic ventrite (Figs. 193, 194) (extracted in part from White 

1962a, Philips 2002). Caenocara tenuipalpa also tends to be 

much smaller than the more commonly seen C. oculata or 

C. inepta.

Identification of female C. tenuipalpa was possible based 

on the form of the maxillary palpi, which are unlike those of 

any other Wisconsin Caenocara species.

Natural History—In Wisconsin, most specimens of C. tenuipalpa were collected using flight intercept, Townes–Malaise, and Lindgren funnel traps. One specimen was obtained 

at UV light and another was swept “from forest understory 

vegetation” in a hardwood forest. 

Phenology—Adult specimens of C. tenuipalpa were recorded in Wisconsin from late May to early September.

Distribution—Caenocara tenuipalpa has been recorded 

north from Massachusetts, Michigan, Ohio, Illinois, south 

into North Carolina and Tennessee, and west to Texas 

(White 1982). 

In this study, specimens were examined from 12 Wisconsin 

counties; they constitute a NEW STATE RECORD and 

new northwestern range extension of the known distribution 

for the species.

Wisconsin Records (Map 44)—The 22 specimens of 

C. tenuipalpa examined during this study were recorded 

from the following localities: Adams Co. (1): Quincy Bluff 

TNC; Dane Co. (1): Swamp Lover’s Inc.; Eau Claire Co. 

(1): Eau Claire County Forest; Grant Co. (4): Blue River 

Sand Barrens SNA; No additional label data; Green Co. 

(1): Abraham’s Woods SNA; Iowa Co. (1): No additional 

label data; Jackson Co. (4): No other locality data; Monroe 

Co. (1): Fort McCoy SNA; Racine Co. (2): Private Property – Arango Residence – Greenbriar Road; Renak-Polak 

Maple-Beech Woods SNA; Rock Co. (1): No other locality 

data; Sauk Co. (2): Spring Green Preserve SNA; Wood Co. 

(3): Power’s Bluff SNA.

Genus Dorcatoma Herbst

[Synonymy modified from White 1962a, 1974, 1982] 

Type Species: Dorcatoma dresdensis Herbst 1792: 

103 (by monotypy). 

Dorkatoma Herbst 1792: 103.

Dorcatoma Herbst; Paykull 1798: 319 (justified 

emendation).

Serrocerus Kugelann 1792: 486.

Dorcatorna Herbst; Westwood 1838: 273 (lapsus calami).

Dorcotoma Herbst; Lea 1924: 44 (lapsus calami).

Nerrocerus Kugelann; Wu 1937: 548 (lapsus calami).

Doratoma Herbst; Hayashi 1951: 4 (lapsus calami).

Dorcadoma Herbst; Horion 1961: 248 (lapsus calami).

Dorkatoma Herbst (1792) was emended as Dorcatoma by 

Paykull (1798) as a justified spelling correction (White 

1974). Five Dorcatoma species are known from North 

America, north of Mexico (White 1982, Philips 2002), three 

of which have been found in Wisconsin. 

Specimens of Dorcatoma strongly resemble those of Byrrhodes, with which they have been frequently confused. In 

1905, Fall clarified Dorcatoma to include those species in 

which “the prosternum is produced behind into two long 

slender horn-like processes,” an important character that 

cannot be seen unless the head and prothoracic ventrite are 

pulled away from the body (Fig. 64) (Philips 2002). Although this structure was adequately described by LeConte 

during his work on the genus, Fall (1905) found more than 

half the species included by LeConte in Dorcatoma lacked 

this structure, while others expressing this character were 

erroneously placed in other genera such as Caenocara and 

Catorama (now Tricorynus) (Fall 1905). Those species lacking the prosternal horn-like processes were removed by Fall 

(1905) and placed into his new genus Eutylistus, which was 

later synonymized under Byrrhodes (White 1971a, c).

Dorcatoma larvae are fungivores, developing within more 

or less woody fungi (White 1962a) generally found growing on dead or dying trees. The ability of Dorcatoma spp. 

to colonize wood-decay fungi was researched in Sweden by 

Jonsell et al. (1999), who studied the effect of distance and 

patch size on dispersal abilities of several beetles known to 

inhabit fungi. Their results showed members of Dorcatoma

to be highly dispersive, and they hypothesized that with this 
General Technical Report FPL–GTR–209

66

ability to colonize distant patches, the beetles were able to 

avoid competition for resources from other fungivores as 

well as escape parasitism (Jonsell et al. 1999). This is especially important because larvae are thought to take more 

than one year to complete development (Jonsell et al. 1999).

The efficiency with which Dorcatoma spp. find mates has 

also been recently studied. Jonsson et al. (2003) discovered 

only females are attracted to the odor of various fruiting 

bodies, after which they attract males to the fungal site with 

a sex pheromone. The pheromone method of locating mates 

was suggested by the authors to be a successful strategy 

even in areas of higher habitat fragmentation when compared with other fungivores where both sexes are attracted 

to the fungus (Jonsson et al. 2003). 

Members of Dorcatoma may be separated from all other 

Wisconsin Ptinidae by a combination of the following characters: eyes not, or slightly, notched; antennae clubbed, with 

last three segments much longer than all preceding segments 

(Fig. 55); prothoracic ventrite produced posteriorly into two 

slender, parallel-sided processes (Fig. 64); prothoracic coxae 

concealed ventrally during body retraction; head strongly 

deflexed so that the mandibles reach the metathoracic 

ventrite (Fig. 196); metathoracic ventrite produced anteriorly into a broad lobe with distinct tarsal grooves (Figs. 80, 

81); elytra not notched at sides for metathoracic legs; appendages highly contractile and received in ventral excavations (Figs. 196, 198, 200); first abdominal ventrite grooved 

for metathoracic legs (extracted in part from Philips 2002). 

The form of the prosternal parallel-sided process (Fig. 64) 

alone may differentiate this genus from all other Wisconsin 

Ptinidae, although there are a few genera for which this 

character has not yet been assessed.

Males and females of Dorcatoma may be separated based on 

their sexually dimorphic antennae. In the males, the 8th and 

9th antennal segments are more strongly produced laterally; 

nearly appearing branched in Dorcatoma pallicornis LeConte and Dorcatoma falli White. The females of these two 

species have the 8th and 9th antennal segments produced 

laterally into a broadly, emarginate triangle. In Dorcatoma 

setulosa LeConte, the difference is more subtle with the 

males having the 8th and 9th antennal segments produced 

laterally into a more broadly, emarginate triangle and the 

females with these segments scarcely produced laterally 

and only slightly emarginate.

Key to the Wisconsin Species of Adult Dorcatoma

[Modified from White 1966a]

1 Pubescence of dorsal surface erect (Figs. 199, 200)................................................................. setulosa LeConte (p. 68)

1’ Pubescence of dorsal surface recumbent (Figs. 195–198).............................................................................................. 2

2 (1’) Metasternal fovea large and circular (Fig. 81)............................................................... pallicornis LeConte (p. 67)

2’ Metasternal fovea narrow and slit-like (Fig. 80) ................................................................................ falli White (p. 66)

Dorcatoma falli White

(Figs. 55, 80, 195, 196; Map 45)

[Synonymy modified from White 1982] 

Dorcatoma dresdensis sensu Fall 1905: 262.

Dorcatoma falli White 1965: 114.

White (1965) described D. falli from specimens erroneously 

thought to be D. dresdensis Herbst (Fall 1905) (see D. pallicornis section).

Capsule Description (Figs. 55, 80, 195, 196)—Length: 

2.1–3.0 mm. Width: 1.3–1.8 mm. Integument Color: dark 

reddish-brown to black; maxillary and labial palpi yellowish 

to reddish-black; antennae and tarsi yellowish to reddishyellow; legs reddish black to black; surface distinctly shining. Body Form: elongate, oval, 1.6X longer than wide.

Vestiture: pubescence yellowish to whitish; short, somewhat sparse, completely recumbent. Head: antennae 

10-segmented, clubbed, combined length of last 

3 antennal segments much longer than all preceding segments combined, segments 8 and 9 moderately produced 

laterally (♀♀) to appearing branched (♂♂), 10th segment 

elongate; surface shining, densely punctate. Pronotum:

short; deeply excavate ventrally to receive head; ventrally 

produced posteriorly into two slender, parallel-sided processes; surface shining, densely punctate. Elytra: humeri 

prominent; laterally with 2 strongly impressed striae, upper 

3rd striae sometimes visible basally; surface densely punctate, not arranged in rows. Metathoracic Ventrite: excavate 

for reception of mesothoracic legs; deeply, longitudinally 

sulcate throughout most of its length; produced in a broadly 

flat lobe anteriorly. Legs: received in ventral excavations. 

Abdomen: with 5 ventrites; 1st ventrite grooved for, and 

nearly concealed by, metathoracic legs.

Diagnosis—Dorcatoma falli may be distinguished from all 

other Wisconsin Dorcatominae by a combination of the following characters: eyes not, or slightly, notched; prothoracic 

coxae concealed ventrally during body retraction; 
Death-Watch and Spider Beetles of Wisconsin

67

prothoracic ventrite produced posteriorly into two slender, 

parallel-sided processes (Fig. 64); pubescence of dorsal 

surface recumbent; elytra with two or three striae 

(Figs. 195, 196); elytra laterally not notched for metathoracic legs; fovea of metathoracic ventrite narrow and slit-like 

(Fig. 80) (extracted in part from Philips 2002).

Natural History—The larvae of D. dresdensis were described by Böving (1954) for specimens collected both in 

Europe as well as in North America. Therefore, it is likely 

that this description is actually a combination of both 

D. falli and D. dresdensis. The North American specimens 

examined, including some from Wisconsin, were said to 

have been collected in a “woody fungus.” During this survey, Wisconsin specimens were collected using Lindgren 

funnel, flight intercept, and Townes–Malaise traps.

Phenology—Adult specimens of D. falli were recorded in 

Wisconsin from mid-May to early August.

Distribution—Dorcatoma falli occurs widely across the 

northern United States and Canada (Fall 1905). Specimens 

have been recorded west from Montana, east to Maryland, 

and south to Missouri, Virginia, and South Carolina (Fall 

1905, White 1982). Böving (1954) reported this species 

from Wisconsin. During this study, specimens were 

recorded from nine counties in Wisconsin.

Wisconsin Records (Map 45)—The 10 specimens of 

D. falli examined during this study were recorded from the 

following localities: Adams Co. (1): Quincy Bluff TNC; 

Green Co. (1): Abraham’s Woods SNA; Marathon Co. 

(1): Big Eau Pleine Woods SNA–Big Eau Pleine County 

Park; Milwaukee Co. (1): Milwaukee; Monroe Co. 

(1): Fort McCoy SNA; Racine Co. (1): Renak–Polak 

Maple–Beech Woods SNA; Sauk Co. (2): Hemlock Draw 

TNC; Sauk County Forest AC; Shawano Co. (1): Jung 

Hemlock–Beech Forest SNA; Wood Co. (1): Powers 

Bluff SNA.

Dorcatoma pallicornis LeConte

(Figs. 81, 197, 198; Map 46)

[Synonymy modified from White 1962a, 1982] 

Dorcatoma pallicornis LeConte 1874: 274.

Dorcatoma foveatum White 1960: 238. 

Dorcatoma pallicornis was described by LeConte (1874). 

During his revision of North American fauna, Fall (1905) 

synonymized D. pallicornis with the European species, Dorcatoma dresdensis Herbst. Later, White (1965) determined 

that D. dresdensis sensu Fall was not conspecific with 

D. dresdensis based on the structure of the metathoracic 

ventrite. Thus, Fall’s description was actually for an unnamed species White described as Dorcatoma falli White 

in Fall’s honor. In this work, White (1965) resurrected to 

specific status D. pallicornis, stating “D. dresdensis Herbst 

resembles D. pallicornis LeConte in the metasternal characters, but the male of the latter bears branched 8th and 9th 

antennal segments similar to those of falli.” White (1962a) 

later synonymized Dorcatoma foveatum White, stating “examination of LeConte’s female type showed it to be distinct 

from dresdensis and identical with foveatum.”

Capsule Description (Figs. 81, 197, 198)—Length: 2.1–

3.1 mm. Width: 1.2–1.8 mm. Integument Color: dark 

reddish-brown to black; maxillary and labial palpi, antennae, and tarsi yellowish to reddish-yellow; legs yellowishblack to black; surface distinctly shining. Body Form:

robust, elongate, oval, 1.7X longer than wide. Vestiture:

pubescence yellowish, short, somewhat sparse, completely 

recumbent. Head: antennae 10-segmented, clubbed, combined length of last 3 antennal segments much longer 

than all preceding segments combined, segments 8 and 9 

moderately produced laterally (♀♀) to appearing branched 

(♂♂), 10th segment elongate; surface shining, with numerous small punctures. Pronotum: short, deeply excavate 

ventrally to receive head, ventrally produced posteriorly 

into two slender, parallel-sided processes; surface shining, 

with numerous small punctures. Elytra: humeri prominent; 

laterally with 2 strongly impressed striae, upper 3rd striae 

sometimes visible basally; punctures of disk not arranged 

in rows. Metathoracic Ventrite: excavate for reception of 

mesothoracic legs; with a longitudinal sulcus terminating in 

a deep fovea towards anterior margin; produced in a broadly 

flat lobe anteriorly. Legs: received in ventral excavations. 

Abdomen: with 5 ventrites; 1st ventrite grooved for, and 

nearly concealed by, metathoracic legs.

Diagnosis—Dorcatoma pallicornis may be distinguished 

from all other Wisconsin Dorcatominae by a combination of 

the following characters: eyes not, or slightly, notched; prothoracic coxae concealed ventrally during body retraction; 

prothoracic ventrite produced posteriorly into two slender, 

parallel-sided processes (Fig. 64); pubescence of dorsal 

surface recumbent; elytra with two or three striae (Figs. 

197, 198); elytra laterally not notched for metathoracic legs; 

fovea of metathoracic ventrite large and circular (Fig. 81) 

(extracted in part from Philips 2002).

Natural History—In Wisconsin, the majority of specimens 

were collected from a single site in Madison, WI. A large 

shelf fungus, determined as Ganoderma applanatum (Pers.) 

Pat., was collected on 03 April 2007 from the side of a dead 

elm tree in the yard of an apartment complex. The fungus 

was placed in a bucket rearing chamber (Fig. 11); adults 

emerged on 17 April 2007, filling the glass jars on the sides 

of the chamber. A few more adults emerged over the next 

several days, but in fewer numbers. Three other specimens 

from Wisconsin were collected, “on shelf like fungus growing on tree snag,” and an additional five specimens were 

obtained in flight intercept traps. 

Phenology—Adult specimens of D. pallicornis were recorded in Wisconsin from early April to mid-August.

Distribution—Dorcatoma pallicornis is known mainly from 

northeastern North America, from Ontario, Maine, New 

Hampshire, and New York, west to Ohio and 
General Technical Report FPL–GTR–209

68

Wisconsin (White 1982). During this study, specimens were 

recorded from five Wisconsin counties.

Wisconsin Records (Map 46)—The 53 specimens of 

D. pallicornis examined during this study were recorded 

from the following localities: Dane Co. (45): Private Property–Madison–4501 Hammersley Dr.; Eau Claire Co. 

(1): Eau Claire County Forest; Marinette Co. (1): Dunbar 

Barrens SNA; Menominee Co. (4): Menominee Tribal Enterprises; Waupaca Co. (2): Mud Lake Bog SNA.

Dorcatoma setulosa LeConte

(Figs. 199, 200; Map 47)

Dorcatoma setulosa LeConte 1865: 242.

Capsule Description (Figs. 199, 200)—Length: 1.6–

2.1 mm. Width: 1.0–1.2 mm. Integument Color: black; 

sometimes dark reddish-black along pronotal and elytral 

margins; maxillary and labial palpi yellowish to reddishyellow; antennae and tarsi yellowish; legs reddish-yellow to 

reddish-black; surface distinctly shining. Body Form: elongate, oval, 1.6X longer than wide. Vestiture: pubescence 

yellowish, short, sparse, erect on dorsal and ventral surface. 

Head: antennae 10-segmented, clubbed, combined length 

of last 3 antennal segments much longer than all preceding 

segments combined, segments 8 and 9 scarcely produced 

laterally and only slightly emarginate (♀♀) to broadly 

triangular and obviously emarginate (♂♂), 10th segment 

elongate; surface shining, with numerous small punctures. 

Pronotum: short; deeply excavate ventrally to receive head; 

ventrally produced posteriorly into two slender, parallelsided processes; surface shining, with numerous small punctures. Elytra: humeri prominent; laterally with 2 strongly 

impressed striae, upper, 3rd striae sometimes visible basally; punctures of disk forming more or less regular rows, 

punctures atx appearing arranged in pairs. Metathoracic 

Ventrite: excavate for reception of mesothoracic legs; with 

a deeply impressed longitudinal sulcus; produced anteriorly 

in a broadly flat lobe. Legs: received in ventral excavations. 

Abdomen: with 5 ventrites; 1st ventrite grooved for and 

nearly concealed by metathoracic legs.

Diagnosis—Dorcatoma setulosa may be distinguished from 

all other Wisconsin Dorcatominae by a combination of the 

following characters: eyes not, or slightly, notched; prothoracic coxae concealed ventrally during body retraction; 

prothoracic ventrite produced posteriorly into two slender, 

parallel-sided processes (Fig. 64); pubescence of dorsal surface erect; elytra with two or three striae (Figs. 199, 200); 

elytra laterally not notched for metathoracic legs (extracted 

in part from Philips 2002).

Natural History—Specimens of D. setulosa are known to 

develop in the fungus, Polyporus cuticularis Fr. (Weiss and 

West 1922, White 1962a, 1982). In Wisconsin, specimens 

were collected using Lindgren funnel, flight intercept and 

Townes–Malaise traps.

Phenology—Adult specimens of D. setulosa were recorded 

in Wisconsin from late June to mid-August.

Distribution—Dorcatoma setulosa is known from much of 

eastern North America, occurring from New Hampshire, 

New York, Pennsylvania, south into Georgia and Louisiana, 

southwest to Kansas, and northwest into Illinois, Michigan, 

and Ohio (White 1982). In this study, specimens were 

examined from 11 Wisconsin counties; they constitute a 

NEW STATE RECORD and new northwestern range 

extension of the known distribution for the species.

Wisconsin Records (Map 47)—The 23 specimens of 

D. setulosa examined during this study were recorded from 

the following localities: Adams Co. (3): Quincy Bluff TNC; 

Dane Co. (2): Swamp Lover’s Inc.; Iron Co. (1): Frog Lake 

and Pines SNA; Juneau Co. (1): Lemonweir Bottomland 

Hardwood Forest SNA; Lafayette Co. (1): Wedel Property– 

~3 mi. north of Argyle; Marinette Co. (1): Dunbar Barrens 

SNA; Milwaukee Co. (9): Cudahy Woods SNA; Rock Co. 

(1): Private Property–1.7 mi. NW Janesville; Sauk Co. 

(1): Hemlock Draw TNC; Shawano Co. (1): Jung Hemlock–Beech Forest SNA; Wood Co. (2): Power’s Bluff 

SNA. 

Genus Petalium LeConte

[Synonymy modified from White 1982]

Type Species: Anobium bistriatum Say 1825: 172 (by 

original description).

Petalium LeConte 1861: 204. 

Rhadine Baudi di Selve 1873: 331.

Synanobium Schilsky 1898: 22.

Radine Baudi di Selve; Schilsky 1899: 36c (lapsus calami).

Fossanobium Pic 1903: 172 (as subgenus).

Rahdine Baudi di Selve; White 1962a: 20 (lapsus calami).

Metapetalium Español 1970: 2 (as subgenus).

Petalium was established by LeConte (1861) and redefined 

by LeConte (1865) based on the first known New World 

species, which Say (1825) described as Anobium bistriatum Say (Ford 1973). Pic (1903, 1912a, respectively) synonymized Rhadine as well as Synanobium with Petalium. 

Fossanobium and Metapetalium were both described as 

subgenera but are currently recognized as synonyms of Petalium (White 1982). Fall (1905) described four new species 

and three subspecies in his revision of the genus, the most 

complete reference to Petalium until 1973, when the genus 

was revised by Ford. Ford’s work described 17 new species 

and elevated Fall’s (1905) three subspecies to specific status. 

During Ford’s examination of the type series of Petalium

seriatum Fall, he discovered a mix of what he determined to 

be three different species: P. seriatum Fall, Petalium whitei 

Ford, and Petalium incisum Ford. This discovery helped 

clarify some of the confusion over determinations of this 

species (e.g., White 1962a). Classification of Petalium as 

presented here is modified from the revisionary work completed by Ford (1973).

Petalium is composed of 23 North American species north 

of Mexico, with species richness greatest in southwestern 
Death-Watch and Spider Beetles of Wisconsin

69

North America and along the east coast, diminishing northward. Six Petalium species have been collected in Wisconsin. Members of this genus have been recorded from several 

species of hardwoods, including Juglans nigra Linnaeus, 

Juglans sp., Robinia pseudoacacia Linnaeus, Robinia sp., 

Quercus ilicifolia Wangenheim, Quercus velutina Lamarck, 

as well as from the softwood genus Pinus, two lianas, 

Celastrus scandens Linnaeus and Rhus toxicodendron Linnaeus, and the shrub/tree Forestiera acuminata Poir. (Ford 

1973). According to the literature, hand-collected specimens 

were generally obtained from the outer layers of dry, pithy, 

woody tissues, rather than from material that was wet, fungus ridden, or infested with other insects (Ford 1973). Species of Petalium have also been collected at UV light.

The generic name Petalium refers to the petal-like expansion of the anterior area of the metathoracic ventrite, which 

conceals the mandibles and prothoracic tarsi during body 

retraction (Fig. 82) (Ford 1973). The shape of the terminal 

maxillary palpomere (Fig. 91), the expansion of the metathoracic ventrite as well as the shape of the second abdominal ventrite (Fig. 208), which is elongate and generally as 

long as ventrites 3–5 combined, serve to distinguish this 

genus from all other Wisconsin ptinid genera. The perforations on the sides of the pronotum (Figs. 202, 204, 206, 208, 

210, 212) are also unique to this genus and are hypothesized 

to represent adaptations whereby the cuticle has inverted to 

provide more efficient muscle attachments for movement of 

the head (Ford 1973). 

Although members of Petalium are readily distinguished 

from other ptinid genera, species determinations are often 

difficult as they share many characteristics and show some 

variation in color and size between the sexes and throughout 

their geographic ranges. For example, Ford (1973) stated 

that “specimens of seriatum, bistriatum, and whitei are usually darker and smaller in the south than those collected further north.” He also noted that males are generally smaller 

than females. However, the key presented in his revision 

does not consider this variation in size. In addition, the degree and distance of punctures on the elytral disk, characters 

used extensively in Ford’s (1973) work, also proved problematic, as examination of material determined by Ford did 

not always agree with the description given in the key. For 

the purpose of this survey, other characters have been chosen to separate Wisconsin species. It should be noted that 

previously known distributions as defined by Ford (1973) 

and White (1982) as well as loaned material for comparison 

were relied on heavily to differentiate species. This genus is 

one of the most difficult groups to determine to species with 

any degree of certainty and is therefore in need of further 

revision to account for possible variations within the species. Future revisionary work should compare species over a 

broad geographic range. Analysis via molecular techniques 

may also prove insightful. 

Males and females of Petalium are not easily separated, although the eyes tend to be larger and less widely separated 

in males. 

Key to the Wisconsin Species of Adult Petalium

[Modified from Fall 1905 and Ford 1973]

1 Pronotum with anterior recurved carina strongly raised and obviously incised or 

 emarginate medially (Figs. 90, 207); pronotal medial hump prominent (Figs. 207–208) ................incisum Ford (p. 71)

1’ Pronotum with anterior recurved carina not incised medially; pronotal medial hump variable ...................................... 2

2 (1’) Pronotal medial hump prominent; 7th antennal segment swollen, 2–3X broader than 

 segments 6 or 8 (Fig. 46); lateral pronotal margins with two perforations usually 

 connected by a shallow sulcus, not extending beyond perforations (Fig. 210)......................... seriatum Fall (p. 72)

2’ Pronotal medial hump not to moderately raised; antennae not as above; lateral pronotal margins variable................... 3

3 (2’) Body dark reddish-brown to blackish........................................................................................................................ 4

3’ Body generally lighter reddish-brown to castaneous, never blackish.............................................................................. 5

4 (3) Body blackish; pronotum reddish or black, coarsely wrinkled; elytral disk shining with short, 

 yellowish, recumbent setae, not distinctly arranged in rows (Fig. 203) .................................bistriatum (Say) (p. 70)

4’ Body dark reddish-brown to blackish; elytral disk covered with golden pubescence, arranged 

 in alternating broad and narrow rows (Fig. 201) (note: rows best viewed using diffuse 

 lighting).......................................................................................................................................alternatum Ford (p. 70)

5 (3’) Larger, 1.8–2.1 mm long; lateral pronotal margins with two perforations connected by 

 deep, crescent-shaped sulcus extending beyond perforations (Fig. 212)......................................whitei Ford (p. 73)

5’ Smaller, <1.8 mm; lateral pronotal margins with two perforations connected by a short, deep 

 sulcus, not extending beyond perforations (Fig. 206)........................................................................... debile Fall (p. 71)
General Technical Report FPL–GTR–209

70

Petalium alternatum Ford

(Figs. 201, 202; Map 48)

Petalium alternatum Ford 1973: 24.

Capsule Description (Figs. 201, 202)—Length: 2.0–

2.4 mm. Width: 0.9–1.1 mm. Integument Color: reddishblack to black; maxillary and labial palpi, antennae, and tarsi yellowish to reddish-yellow; head black; ventral surface 

sometimes lighter. Body Form: moderately elongate, subcylindrical, 2.3X longer than wide. Vestiture: pubescence 

yellowish, recumbent; dense and arranged in rows on elytra 

(note: best seen using diffuse lighting); short and sparse 

on metathoracic ventrite and abdomen. Head: maxillary 

palpi with terminal segment emarginate apically; 

antennae 11-segmented, clubbed, combined length of last 

3 antennal segments much longer than all preceding segments combined, pedicel large and spherical, segment 3 

projecting laterally, appearing more or less triangular, segment 5 with a finger-like projection that exceeds the width 

of segment 3; surface wrinkled, granulate. Pronotum:

moderately gibbous; medial hump distinct, but not strongly 

raised; perforations of lateral surface connected by a deep, 

crescent-shaped sulcus; surface wrinkled, granulate. Elytra:

rather strongly convex; notched at sides for prothoracic, mesothoracic, and metathoracic legs. Metathoracic Ventrite:

excavate for reception of mesothoracic legs; anteriorly with 

a petal-like expansion concealing the mandibles during body 

retraction; posteriorly with a shallow, longitudinal sulcus. 

Legs: received in ventral excavations. Abdomen: with 

5 ventrites; 1st ventrite grooved for the metathoracic legs; 

2nd ventrite elongate, subquadrate, as long as ventrites 3–

5 combined.

Diagnosis—Petalium alternatum may be distinguished from 

all other Wisconsin Ptinidae by a combination of the following characters: metathoracic ventrite with petal-like expansion (e.g., Fig. 82); second abdominal ventrite elongate; 

body dark reddish-brown to blackish; elytral disk vested 

with rows of golden pubescence, which is arranged in rows 

(Fig. 201). Ford (1973) stated that this species could be confused with darker specimens of P. seriatum but may be distinguished from them by the unusual form of the antennae, 

which was said to have “segments 3, 5, and 7 strongly produced inward, 5 with fingerlike projection exceeding width 

of 3 or 7, 7 longer than 3.” Ford illustrated the antennal 

forms of most species, but an illustration of the antennae of 

P. alternatum was not provided. Specimens collected from 

Wisconsin do not clearly follow Ford’s description of the 

antennae, nor did a specimen from the FMNH determined 

by Ford. Wisconsin specimens of these two similar species 

are therefore separated based on elytral pubescence: dense 

and arranged in distinct rows in P. alternatum; less dense, 

and not arranged in rows in P. seriatum. 

Natural History—The holotype of this species was collected using a light trap (Ford 1973). Other specimens have 

been reported from Forestiera acuminata (Ford 1973). In 

Wisconsin, specimens were collected using Lindgren funnel 

and flight intercept traps. 

Phenology—Adult specimens of P. alternatum were collected in Wisconsin from early June to late August.

Distribution—This species has been recorded from Mississippi, Texas, and Indiana (Ford 1973, White 1982). In 

this study, specimens were examined from three Wisconsin 

counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 48)—The four specimens of P. 

alternatum examined during this study were recorded from 

the following localities: Dane Co. (2): Swamp Lover’s Inc.; 

Grant Co. (1): Dewey Heights Prairie SNA–Nelson Dewey 

State Park; Trempealeau Co. (1): Perrot State Park.

Petalium bistriatum (Say)

(Figs. 45, 203, 204; Map 49)

[Synonymy modified from White 1962a, Ford 1973] 

Anobium bistriatum Say 1825: 235.

Petalium bistriatum (Say); LeConte 1865: 235. 

Petalium bistriatum bistriatum (Say); White 1962a: 21.

Capsule Description (Figs. 45, 203, 204)—Length: 1.5–

1.9 mm. Width: 0.6–0.8 mm. Integument Color: reddishblack to black; maxillary and labial palpi, antennae, and 

tarsi generally yellowish to reddish-yellow; pronotum red, 

reddish-black, or black; elytra blackish; metathoracic ventrite reddish, reddish-black, or blackish; abdomen usually 

reddish. Body Form: moderately elongate, subcylindrical, 

2.4X longer than wide. Vestiture: pubescence whitish to 

yellowish, recumbent, short. Head: maxillary palpi with terminal segment emarginate apically; antennae 11-segmented, 

clubbed, combined length of last 3 antennal segments much 

longer than all preceding segments combined, pedicel large 

and spherical, segments 3 and 5 projecting laterally, appearing finger-like; surface wrinkled, granulate. Pronotum:

gibbous; medial hump not strongly raised; perforations of 

lateral surface connected by a deep, crescent-shaped sulcus; 

surface wrinkled, granulate. Elytra: notched at sides for 

prothoracic, mesothoracic, and metathoracic legs; punctures 

smaller and more widely spaced, becoming nearly obsolete 

on the apical half; surface shining. Metathoracic Ventrite:

excavate for reception of mesothoracic legs; anteriorly with 

a petal-like expansion concealing the mandibles during body 

retraction; posteriorly with a shallow, longitudinal sulcus. 

Legs: received in ventral excavations. Abdomen: with 

5 ventrites; 1st ventrite grooved for the metathoracic legs; 

2nd ventrite elongate, subquadrate, as long as ventrites 3-

5 combined.

Diagnosis—Petalium bistriatum may be distinguished from 

all other Wisconsin Ptinidae by a combination of the following characters: metathoracic ventrite with petal-like expansion (e.g., Fig. 82); second abdominal ventrite elongate; 

elytra blackish, shiny, usually contrasting to the reddish, 
Death-Watch and Spider Beetles of Wisconsin

71

roughly granulate pronotum (Fig. 203); elytral pubescence 

short and not arranged in rows. Ford (1973) stated teneral 

specimens of P. bistriatum could be confused with P. whitei, 

but may be distinguished from them by the pronotum being 

moderately gibbous in P. bistriatum and not at all gibbous in 

P. whitei. The punctures of the elytral disk will also aide in 

separation of these two species. In P. bistriatum, the elytral 

punctures become smaller and more widely spaced apically, 

nearly obsolete on the apical half, whereas the elytral punctures of P. whitei are more or less distinct from base to apex 

(Ford 1973).

Natural History—Quercus ilicifolia and Q. velutina have 

been reported as hosts for P. bistriatum (White 1982). White 

(1962a) stated that this species is frequently swept from low 

vegetation. In Wisconsin, specimens were collected using 

Lindgren funnel, Townes–Malaise, and flight intercept traps.

Phenology—Adult specimens of P. bistriatum were collected in Wisconsin from early July to mid-August. 

Distribution—Petalium bistriatum is widely distributed 

throughout eastern North America, with its range extending from New England, south to Florida and as far west 

as Texas, Louisiana, Arkansas, and Missouri (Ford 1973, 

White 1982). In this study, specimens were examined from 

four Wisconsin counties; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 49)—The nine specimens of 

P. bistriatum examined during this study were recorded 

from the following localities: Columbia Co. (1): Rocky 

Run SNA; Dane Co. (4): Swamp Lover’s Inc.; Juneau Co. 

(3): Lemonweir Bottomland Hardwood Forest SNA; 

Sauk Co. (1): Spring Green Preserve SNA.

Petalium debile Fall

(Figs. 205, 206; Map 50)

[Synonymy modified from Ford 1973, White 1982] 

Petalium bistriatum debile Fall 1905: 217.

Petalium debile Fall; Ford 1973: 32 (new status).

Capsule Description (Figs. 205, 206)—Length: 1.8 mm. 

Width: 0.7–0.8 mm. Integument Color: reddish-brown to 

brown; maxillary and labial palpi, antennae, and tarsi yellowish to reddish-yellow. Body Form: moderately elongate, 

subcylindrical, 2.5X longer than wide. Vestiture: pubescence yellowish, recumbent, sparsely covering elytra, short 

and sparse on metathoracic ventrite and abdomen. Head:

maxillary palpi with terminal segment emarginate apically; 

antennae 11-segmented, clubbed, combined length of last 

3 antennal segments much longer than all preceding segments combined, pedicel large and spherical, segment 3 

broadly triangular, segment 5 projecting laterally, appearing 

finger-like; surface wrinkled, granulate. Pronotum: feebly 

gibbous; medial hump not evident; perforations of lateral 

surface connected by a short, sometimes interrupted, deep 

sulcus not extending beyond perforations; surface wrinkled, 

granulate. Elytra: notched at sides for prothoracic, 

mesothoracic, and metathoracic legs; punctures small and 

shallow. Metathoracic Ventrite: excavate for reception of 

mesothoracic legs; anteriorly with a petal-like expansion 

concealing the mandibles during body retraction; posteriorly with a shallow, longitudinal sulcus. Legs: received in 

ventral excavations. Abdomen: with 5 ventrites; 1st ventrite 

grooved for the metathoracic legs; 2nd ventrite elongate, 

subquadrate, as long as ventrites 3–5 combined.

Diagnosis—As noted in the diagnosis for P. whitei, specimens of P. debile may be easily confused with those of 

P. whitei. The Wisconsin specimens examined so closely resembles the latter species that they are determined to P. debile with some reservation. However, the smaller size of the 

specimens as well as the perforations of the pronotum connected by a short, deep sulcus that does not extend beyond 

the perforation to form a crescent shape (Fig. 206) support 

this determination. It is possible, however, that further 

comparison and genetic studies of these two species may 

eventually lead to their synonomy. In fact, two of the three 

P. debile specimens known from Wisconsin were obtained 

during the collecting event described under the diagnosis for 

P. whitei, supporting this hypothesis. 

Natural History—Ford (1973) examined a specimen of 

P. debile found on M. borealis. In Wisconsin, two specimens 

were collected at UV light and one from a Townes–Malaise 

trap. 

Phenology—Adults of P. debile were collected in Wisconsin 

from late July to late August.

Distribution—Petalium debile is known mostly from the 

southeastern United States (Ford 1973, White 1982). Ford 

(1973) recorded this species from Florida, Texas, Georgia, 

and New Jersey. One specimen from Indiana was examined 

during this survey from the FMNH. In this study, specimens 

were examined from two Wisconsin counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 50)—The three specimens of 

P. debile examined during this study were recorded from the 

following localities: Dane Co. (1): Madison Nevin Hatchery; Racine Co. (2): Private Property–Arango Residence–

Greenbriar Road.

Petalium incisum Ford

(Figs. 82, 90, 207, 208; Map 51)

Petalium incisum Ford 1973: 9.

Capsule Description (Figs. 82, 90, 207, 208)

Length: 2.1–2.2 mm. Width: 0.8–0.9 mm. Integument 

Color: reddish-brown to dark reddish-brown; maxillary and 

labial palpi, antennae, and tarsi yellowish to reddish-yellow. 

Body Form: moderately elongate, subcylindrical, 2.4X longer than wide. Vestiture: pubescence yellowish, recumbent; 

short and sparse on abdomen and metathoracic ventrite, 
General Technical Report FPL–GTR–209

72

slightly longer dorsally. Head: maxillary palpi with 

terminal segment emarginate apically; antennae 11-segmented, clubbed, combined length of last 3 antennal segments 

much longer than all preceding segments combined, pedicel 

large and spherical, segments 3 and 5 projecting laterally, 

appearing finger-like; surface wrinkled, granulate. Pronotum: gibbous; with a prominent medial hump; anterior 

recurved carina strongly raised and incised to weakly emarginate medially; perforations of lateral surface connected by 

a rather deep sulcus that may extend past the perforation; 

surface wrinkled, granulate. Elytra: notched at sides for 

prothoracic, mesothoracic, and metathoracic legs; surface 

punctate. Metathoracic Ventrite: excavate for reception 

of mesothoracic legs; anteriorly with a petal-like expansion 

concealing the mandibles during body retraction; posteriorly with a shallow, longitudinal sulcus. Legs: received in 

ventral excavations. Abdomen: with 5 ventrites; 1st ventrite 

grooved for the metathoracic legs; 2nd ventrite elongate, 

subquadrate, as long as ventrites 3–5 combined.

Diagnosis—Petalium incisum is readily distinguished from 

all other Wisconsin Ptinidae by a combination of the following characters: anterior recurved carina of pronotum strongly raised and obviously incised or emarginate medially 

(Fig. 90); metathoracic ventrite with petal-like expansion 

(Fig. 82); second abdominal ventrite elongate. The extent of 

pronotal emargination appears to vary, from strongly incised 

to weakly emarginate. 

Natural History—The holotype of this species was reared 

from Rhus toxicodendron by Ford. Petalium incisum has 

also been recorded from Robinia pseudacacia and Celastrus 

scandens (Ford 1973). In Wisconsin, specimens were collected using Lindgren funnel, Townes–Malaise, cantharidinbaited flight intercept, and unbaited flight intercept traps.

Phenology—Adult specimens of P. incisum were collected 

in Wisconsin from early July to mid-September. The majority of records for this species from eastern North American 

collections occurred in June and July (Ford 1973). 

Distribution—Petalium incisum occurs widely across eastern North America, with its range extending as far west as 

Texas and Missouri and as far south as Florida (Ford 1973, 

White 1982). This species has been found as far north as 

New York, Maryland, and Pennsylvania (Ford 1973, White 

1982). In this study, specimens were examined from seven 

Wisconsin counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 51)—The 35 specimens of P. incisum examined during this study were recorded from 

the following localities: Dane Co. (21): Swamp Lover’s 

Inc.; Grant Co. (1): No other locality data; Green Co. 

(1): Browntown Oak Forest SNA; Jefferson Co. (4): Kettle 

Moraine Oak Opening SNA; Ozaukee Co. (1): UW–Milwaukee Field Station; Racine Co. (2): Private Property–

Arango Residence–Greenbriar Road.; Rock Co. (5): Private 

Property–1.7 mi. NW Janesville.

Petalium seriatum Fall

(Figs. 46, 209, 210; Map 52)

Petalium seriatum Fall 1905: 215.

Fall’s (1905) original type series consisted of three species, 

which he initially considered variations of P. seriatum (Ford 

1973). Ford (1973) clarified Fall’s description by separating 

out and describing two new species from the type series. 

Capsule Description (Figs. 46, 209, 210)—Length: 1.6–

1.8 mm. Width: 0.7–0.8 mm. Integument Color: reddishbrown; maxillary and labial palpi, antennae, and tarsi yellowish to reddish-yellow. Body Form: moderately elongate, 

subcylindrical, 2.3X longer than wide. Vestiture: pubescence yellowish, recumbent, somewhat dense and arranged 

in indistinct rows on elytra; short and sparse on metathoracic ventrite and abdomen. Head: maxillary palpi with terminal segment emarginate apically; antennae 11-segmented, 

clubbed, combined length of last 3 antennal segments much 

longer than all preceding segments combined, pedicel large 

and spherical, segment 3 broadly triangular, segment 5 projecting laterally, appearing finger-like, segment 7 swollen 

2–3X larger than segments 6 or 8; surface wrinkled, granulate. Pronotum: moderately gibbous; medial hump distinct, 

but not strongly raised; perforations of lateral surface connected by a shallow sulcus; surface wrinkled, granulate. 

Elytra: notched at sides for prothoracic, mesothoracic, and 

metathoracic legs; strial punctures usually strong and closer 

together, distinct beyond middle of elytral disk. Metathoracic Ventrite: excavate for reception of mesothoracic legs; 

anteriorly with a petal-like expansion concealing the mandibles during body retraction; posteriorly with a shallow, 

longitudinal sulcus. Legs: received in ventral excavations. 

Abdomen: with 5 ventrites; 1st ventrite grooved for the 

metathoracic legs; 2nd ventrite elongate, subquadrate, as 

long as ventrites 3–5 combined.

Diagnosis—Petalium seriatum may be distinguished from 

all other Wisconsin Ptinidae by a combination of the following characters: seventh antennal segment swollen and about 

twice as large as segments six or eight (Fig. 46); metathoracic ventrite with petal-like expansion (e.g., Fig. 82); second abdominal ventrite elongate; body reddish-brown. Ford 

(1973) described this species as having the pronotal medial 

hump “large and flanked each side by oblique depressions.” 

The Wisconsin specimens examined, however, show a far 

less distinctly raised medial hump. Specimens of P. seriatum

may be confused with those of P. whitei; however, the latter 

species does not have the seventh antennal segment swollen 

(Ford 1973).

Natural History—Larvae of P. seriatum were described 

by Böving (1954) from specimens reared from Juglans sp. 

as well as from a “small dead branch.” Other known associations include Juglans nigra Linnaeus and Pinus sp. 

(White 1982). Petalium seriatum has also been collected on 
Death-Watch and Spider Beetles of Wisconsin

73

Mimosa borealis Gray (Ford 1973). Wisconsin specimens 

were collected using flight intercept, Lindgren funnel, and 

Townes–Malaise traps.

Phenology—Adult specimens of P. seriatum were collected 

in Wisconsin from late May to mid-August.

Distribution—Petalium seriatum is widely distributed 

throughout eastern North America. This species occurs from 

Florida, west to Louisiana, Texas, Kansas, and Missouri, 

and North into Indiana, Ohio, Pennsylvania, Maryland, and 

Ontario, Canada (Ford 1973, White 1982). In this study, 

specimens were examined from four Wisconsin counties; 

they constitute a NEW STATE RECORD.

Wisconsin Records (Map 52)—The 10 specimens of P. seriatum examined during this study were recorded from the 

following localities: State only (1); Burnett Co. (1): Crex 

Meadows SWN; Dane Co. (6): Madison; Swamp Lover’s 

Inc.; No additional data; Grant Co. (1): Dewey Heights 

Prairie SNA–Nelson Dewey State Park; Polk Co. (1): Governor Knowles State Forest.

Petalium whitei Ford

(Figs. 91, 211, 212; Map 53)

Petalium whitei Ford 1973: 31.

Petalium whitei was named by Ford (1973) in recognition 

of the substantial amount of work done by Dr. Richard E. 

White on this family of beetles.

Capsule Description (Figs. 91, 211, 212)—Length: 

1.8–2.1 mm. Width: 0.7–0.8 mm. Integument Color:

reddish-brown; maxillary and labial palpi, antennae, and 

tarsi yellowish to reddish-yellow. Body Form: moderately 

elongate, subcylindrical, 2.5X longer than wide. Vestiture:

pubescence yellowish, recumbent, sparsely covering elytra, 

short and sparse on metathoracic ventrite and abdomen. 

Head: maxillary palpi with terminal segment emarginate 

apically; antennae 11-segmented, clubbed, combined length 

of last 3 antennal segments much longer than all preceding 

segments combined, pedicel large and spherical, segment 3 

broadly triangular, segment 5 projecting laterally, appearing 

finger-like; surface wrinkled, granulate. Pronotum: feebly 

gibbous; medial hump evident, but not strongly raised; perforations of lateral surface connected by a deep to shallow, 

crescent-shaped sulcus that extends beyond perforations; 

surface wrinkled, granulate. Elytra: notched at sides for 

prothoracic, mesothoracic, and metathoracic legs; punctures 

distinct from base to apex, closer together on anterior third. 

Metathoracic Ventrite: excavate for reception of mesothoracic legs; anteriorly with a petal-like expansion concealing 

the mandibles during body retraction; posteriorly with a 

shallow, longitudinal sulcus. Legs: received in ventral excavations. Abdomen: with 5 ventrites; 1st ventrite grooved for 

the metathoracic legs; 2nd ventrite elongate, subquadrate, as 

long as ventrites 3–5 combined.

Diagnosis—Petalium whitei may be distinguished from all 

other Wisconsin Ptinidae by a combination of the following 

characters: petal-like expansion of the metathoracic ventrite 

(e.g.,Fig. 82); elongate second abdominal ventrite; reddishbrown body; seventh antennal segment not swollen; perforations of lateral surface connected by a deeper to shallower, 

crescent-shaped sulcus that extends beyond perforations 

(Fig. 212). 

Some specimens of P. whitei closely resemble those of Petalium debile Fall, from which they are separated in Ford’s 

(1973) key by size. However, the couplet that separates 

them contains overlapping size ranges, which may cause 

smaller specimens of P. whitei to key out as P. debile. As the 

latter species is less common with a more southeastern distribution, it is likely that many of the Wisconsin specimens 

collected are smaller examples of P. whitei. 

The form of the lateral pronotal perforations in Wisconsin 

specimens generally supported their determination; however, a single collection event at UV light demonstrated 

variation in this character. Of the specimens collected, half 

had the typical deep, crescent-shaped sulcus connecting the 

two perforations, whereas the other half had the perforations 

connected by an exceedingly shallow sulcus. Some members of the latter group had the sulcus extending slightly 

past the more interior perforation, appearing partially crescent shaped. This type of variation was not observed by 

Ford (1973): “large series of species bred from the same 

host plant show very little variation, or large series of a species collected at light on the same night display hardly any 

differences.” Brief examination of the male genitalia of one 

specimen from each group, however, did not reveal any inherent differences, thus supporting their identity as P. whitei. 

Natural History—The holotype of P. whitei was collected 

using a UV light trap (Ford 1973). In Wisconsin, most 

specimens were collected at UV light. Specimens were also 

obtained using Lindgren funnel and flight intercept traps.

Phenology—Adult specimens of P. whitei were collected 

in Wisconsin from early June to early August.

Distribution—Petalium whitei is widely distributed 

throughout eastern North America. It has been recorded 

as far west as Texas, and south from Florida, Georgia, and 

Mississippi, north to Massachusetts, Pennsylvania, and New 

York (Ford 1973, White 1982). In this study, specimens 

were examined from five Wisconsin counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 53)—The 17 specimens of 

P. whitei examined during this study were recorded from the 

following localities: Adams Co. (1): Quincy Bluff TNC; 

Iowa Co. (1): Arena Pines–Sand Barrens SNA; Lafayette 

Co. (1): Wedel Property– ~3 mi. north of Argyle; Racine 

Co. (12): Private Property–Arango Residence–Greenbriar 

Road; Sauk Co. (2): Bakken’s Pond; Gatshall AC.
General Technical Report FPL–GTR–209

74

Genus Protheca LeConte

[Synonymy modified from White 1979, 1982, Philips 2002] 

Type Species: Protheca hispida LeConte 1865: 241 (designated by Lucas 1920: 541).

Protheca LeConte 1865: 241.

Picatoma Lepesme 1947: 224.

Photheca LeConte; Español 1972: 75 (lapsus calami).

Protheca was proposed by LeConte (1865) to include two 

North American species: Protheca hispida LeConte and 

Protheca puberula LeConte, the latter of which was subsequently transferred to Sculptotheca (White 1979). Species 

of Protheca are found exclusively in the Americas (White 

1979), with one species occurring in North America north 

of Mexico. Members of Protheca are largely unknown, 

however. White (1979) provided a complete revision of the 

genus for worldwide fauna in which he gave descriptions for 

20 new species, 11 of which were described from a single 

specimen. 

Members of Protheca may be distinguished from all other 

North American Dorcatominae by a combination of the 

following characters: eyes entire, not incised; antennae 

11-segmented; prothoracic coxae concealed ventrally during 

body retraction; elytra faintly punctate-striate; elytra at sides 

notched for metathoracic legs; pubescence bristling; metathoracic ventrite with distinct tarsal grooves; first ventrite 

grooved for reception of the metathoracic legs. 

As with many species of Protheca, the only certain 

method of separating males from females is by genitalic 

examination (White 1979).

Protheca hispida LeConte

(Figs. 53, 213, 214; Map 54)

Protheca hispida LeConte 1865: 241.

Capsule Description (Figs. 53, 213, 214)—Length: 1.6 

mm. Width: 1.0 mm. Integument Color: reddish-brown to 

castaneous; maxillary and labial palpi, antennae, and tarsi 

reddish-yellow to yellowish. Body Form: oblong, oval, 

1.7X longer than wide. Vestiture: pubescence yellowish to 

whitish; body covered in semi-recumbent to erect, dense, 

bristling setae, changing in direction, appearing as darker 

spots on the elytra. Head: antennae 11-segmented, clubbed, 

combined length of last 3 antennal segments much longer 

than all preceding segments combined; surface with both 

large and small punctures. Pronotum: elongate, laterally 

compressed; surface with both large and small punctures. 

Elytra: grooved at side for mesothoracic and metathoracic 

legs; surface distinctly, densely punctate. Metathoracic 

Ventrite: excavate for reception of mesothoracic legs; 

deeply, longitudinally sulcate at center from base to apex, 

wider mesally; produced anteriorly into a rounded lobe 

terminating in a somewhat hooked knob; surface with both 

large and small punctures. Legs: received in ventral 

excavations. Abdomen: with 5 ventrites; 1st ventrite 

grooved for and nearly concealed by metathoracic legs; 

ventrite sutures curving upward medially.

Diagnosis—This species most closely resembles S. puberula but may be immediately distinguished from it by the 

11-segmented antennae (Fig. 53) and pubescence of the dorsal surface changing in direction, which appears as darker 

spots on the elytra (Figs. 213, 214).

Natural History—Remarkably little is known of the natural 

history of P. hispida. White (1979) reported one specimen 

“from a tulip tree.” Larvae of P. hispida were described by 

Böving (1954) from specimens collected “in Liriodendron” 

from a “single, imperfect larval skin.” The Wisconsin specimen collected was obtained using a flight intercept trap 

baited with cantharidin (although the chemical bait is considered incidental). 

Phenology—The single adult specimen of P. hispida was 

recorded in Wisconsin during a mid- to late July trap sampling interval.

Distribution—Protheca hispida is widely distributed 

throughout eastern North America, having been recorded 

from New York and Ohio, south to Florida and Texas. In this 

study, one specimen was examined from a single Wisconsin 

county; it constitutes a NEW STATE RECORD and new 

northwestern range extension of the known distribution for 

the species.

Wisconsin Records (Map 54)—A single specimen was 

examined during this study from the following location: 

Milwaukee Co. (1): Cudahy Woods SNA.

Genus Sculptotheca Schilsky

[Synonymy modified from White 1982] 

Type Species: Stagetus hilleri Schilsky (by monotypy).

Sculptotheca Schilsky 1900: 16 (as subgenus).

This genus contains one species in North America, north 

of Mexico. Members of Sculptotheca may be distinguished 

from all other North American Dorcatominae by a combination of the following characters: eyes entire, not incised; 

antennae nine-segmented; prothoracic coxae concealed ventrally during body retraction; elytra punctate-striate; elytra 

at sides notched for metathoracic legs; pubescence bristling; 

metathoracic ventrite with distinct tarsal grooves; first ventrite grooved for reception of the metathoracic legs.

Males and females are not readily separable; however, Fall 

(1905) stated that the abdomen of males is distinctly flattened to slightly concave medially. 

Sculptotheca puberula (LeConte)

(Figs. 54, 215, 216; Map 55)

[Synonymy modified from White 1979, 1982] 
Death-Watch and Spider Beetles of Wisconsin

75

Protheca puberula Leconte 1865: 241.

Sculptotheca puberula (LeConte); Español 1973: 62-63.

This species was transferred from Protheca by Español 

(1973) on the basis of its nine-segmented antennae and lateral lobes of the male genitalia without “palplike objects” 

(White 1979).

Capsule Description (Figs. 54, 215, 216)—Length: 1.5–

2.2 mm. Width: 0.9–1.1 mm. Integument Color: dark reddish-brown to dark brown throughout; maxillary and labial 

palpi, antennae, and tarsi reddish to reddish-yellow. Body 

Form: oblong, oval, 1.8X longer than wide. Vestiture:

pubescence yellowish; body covered in semi-recumbent to 

erect, bristling setae; not, to slightly changing in direction 

dorsally. Head: antennae 9-segmented, clubbed, combined 

length of last 3 antennal segments much longer than all 

preceding segments combined; with cup-like excavation 

beneath for reception of the antennae; surface with both 

large and small punctures. Pronotum: elongate; laterally 

compressed; surface with both large and small punctures. 

Elytra: grooved at sides for mesothoracic and metathoracic 

legs; surface distinctly punctate-striate, arranged in rows. 

Metathoracic Ventrite: excavate for reception of mesothoracic legs; deeply, longitudinally sulcate at center from base 

to apex; produced anteriorly in a rounded lobe; surface with 

both large and small punctures. Legs: received in ventral excavations. Abdomen: with 5 ventrites; 1st ventrite grooved 

for and nearly concealed by the metathoracic legs; slightly 

flattened to concave medially.

Diagnosis—This species resembles the morphologically 

similar P. hispida but is readily separated from it by the 

nine-segmented antennae (Fig. 54) and pubescence of 

dorsal surface not, or only slightly changing in direction 

(Figs. 215, 216). 

Natural History—White (1969a) recorded three specimens 

of S. puberula in Virginia from low foliage in the evenings 

between late June and early July. In Wisconsin forests, 

S. puberula is the most frequently collected ptinid using 

passive trapping techniques. The majority of Wisconsin 

specimens of S. puberula were collected using Lindgren 

funnel, flight intercept, and Townes–Malaise traps. A small 

number of specimens were recovered from pitfall traps, at 

light, and in cantharidin-baited traps. One specimen was 

collected by beating oak and maple branches. Two others 

are reported from Ulmus americana Linnaeus and “nonwilting Quercus.” Specimens were obtained at traps utilizing ipsdienol, cantharidin, or synthetic serricornin, although 

it is not clear as to whether any of these compounds had any 

effect on attracting S. puberula as this species is so commonly collected. 

Phenology—Adult specimens of S. puberula were collected 

in Wisconsin from mid-June to early September.

Distribution—Sculptotheca puberula is widely distributed 

throughout eastern North America, as far north as Maryland, 

Michigan, Wisconsin, and Pennsylvania, extending south 

into Florida (White 1982). Wisconsin currently represents 

the western-most boundary of this species. During this 

study, specimens were recorded from 29 counties throughout Wisconsin.

Wisconsin Records (Map 55)—The 261 specimens of 

S. puberula examined during this study were recorded from 

the following localities: State only (2); Adams Co. 

(25): Quincy Bluff TNC; Barron Co. (1): Kriska Residence; Buffalo Co. (2): Engel Farm Property; Clark Co. 

(3): Schmidt Maple Woods SNA; Columbia Co. (7): Rocky 

Run SNA; Dane Co. (34): Swamp Lover’s Inc.; Douglas 

Co. (1): Brule River State Forest; Eau Claire Co. (5): Augusta State Wildlife Area; UW Eau Claire Campus; Grant 

Co. (7): No additional label data; Wyalusing State Park; 

Green Co. (7): Abraham’s Woods SNA; Iowa Co. 

(6): LWRSGA Avoca Unit; Ridgeway Pine Relict SNA; 

Tower Hill State Park; No other locality data; Jackson Co. 

(16): Black River State Forest; Black River State Forest–

Castle Mound Pine Forest SNA; No additional locality data; 

La Crosse Co. (2): West Salem PC; Lafayette Co. 

(37): Wedel Property– ~3 mi. north of Argyle; Marathon 

Co. (1): Big Eau Pleine Woods SNA–Big Eau Pleine County Park; Marinette Co. (6): Bloch Oxbow SNA; Dunbar 

Barrens SNA; Marquette Co. (2): Fox River Wildlife Refuge; Menominee Co. (3): Menominee Tribal Enterprises; 

Private Property–Legend Lake–Spirit Island Road; 

Milwaukee Co. (6): Cudahy Woods SNA; Racine Co. 

(3): Renak–Polak Maple–Beech Woods SNA; Richland 

Co. (2): Gotham Jack Pine Barrens; No other locality data; 

Rock Co. (2): Private Property–1.7 mi. NW Janesville; 

Sauk Co. (58): Bakken’s Pond; Hemlock Draw TNC; Just 

north of Spring Green–Spring Green Preserve TNC; Mirror 

Lake State Park–Echo Rock Trail; Sheboygan Co. 

(13): Kettle Moraine Red Oaks SNA; Trempealeau Co. 

(2): Perrot State Park; Walworth Co. (2): Kettle Moraine 

Oak Opening SNA; Waukesha Co. (1): Kettle Moraine 

State Forest; Waushara Co. (1): D. Balliet Property; 

Wood Co. (4): Griffith St. Nursery; Powers Bluff SNA.

Genus Stagetus Wollaston

[Synonymy modified from White 1982, Philips 2002] 

Type Species: Stagetus hirtulus Wollaston 1861: 

12 (designated by White 1974: 450).

Theca Mulsant and Rey 1860: 293.

Stagetus Wollaston 1861: 1.

Anomotheca Schilsky 1899: 40a.

Thecha Mulsant and Rey; Español 1968: 103 (lapsus 

calami).

Anotheca Schilsky; Español 1969: 109 (lapsus calami).

This genus contains two species in North America, north of 

Mexico: Stagetus profundus (LeConte) and Stagetus grossus

White. Stagetus profundus is the only species that occurs 
General Technical Report FPL–GTR–209

76

in Wisconsin. Members of this genus may be distinguished 

from all other North American Dorcatominae by a combination of the following characters: prothoracic coxae visible 

during body retraction; anterior metasternal process not 

concealing mandibles; elytra with distinctly impressed striae 

throughout from base to apex; pubescence dense and bristling; first ventrite grooved for reception of the metathoracic 

legs.

Stagetus profundus (LeConte)

(Figs. 217, 218; Map 56)

[Synonymy modified from White 1962a, 1982] 

Theca profundus LeConte 1865: 235.

Theca striatopunctatus LeConte 1884: 22.

Stagetus profundus (LeConte); Leng 1920: 243.

Capsule Description (Figs. 217, 218)—Length: 3.0 mm. 

Width: 1.4 mm. Integument Color: dark reddish-black to 

black throughout; maxillary and labial palpi, and antennae 

yellowish-orange. Body Form: elongate, robust, 2.2X longer than wide. Vestiture: pubescence whitish to dull yellowish, moderately dense, slightly obscuring surface sculpture, 

erect on dorsal surface and head, mostly recumbent with 

intermixed erect setae on ventral surface. Head: antennae 

11-segmented, clubbed, combined length of last 3 antennal 

segments much longer than all preceding segments combined; surface rather densely punctate, with both large and 

small punctures. Pronotum: widest at base, narrowing toward apex; slightly concave laterally; lateral margins nearly 

straight; surface with both large and small punctures, large 

punctures at side with puncture rim obsolete toward anterior 

margin. Elytra: each with 10 complete striae; humeri distinct; notched at sides for metathoracic legs. Metathoracic 

Ventrite: excavate for reception of mesothoracic legs; deeply, longitudinally grooved at center; with larger punctures 

laterally and on anterior 0.5, smaller punctures medially 

to posterior margin. Legs: received in ventral excavations; 

prothoracic and mesothoracic coxae visible during body retraction, separated by a diamond/cross-shaped, metasternal 

process, which is distinctly rounded apically (often held between mandibles during body retraction). Abdomen: with 

5 ventrites; 1st ventrite grooved for, and largely concealed 

by, the metathoracic legs.

Diagnosis—Specimens of S. profundus may be distinguished from all other North American Dorcatominae by a 

combination of the following characters: prothoracic coxae 

visible during body retraction; anterior metasternal process 

diamond shaped, rounded apically, not concealing the mandibles; each elytron with 10 complete striae (Fig. 217); pubescence dense and bristling (Figs. 217, 218); first ventrite 

grooved for reception of the metathoracic legs (Fig. 218); 

length less than 3.0 mm. 

Although the Wisconsin specimen of S. profundus collected 

during this survey is the first member of the genus I have 

ever encountered, the descriptions given by Fall (1905) 

and White (1962a) leave little doubt as to its determination 

with the exception of the punctation on the head. Stagetus 

profundus is said to have the head “sparsely not coarsely 

punctate” (Fall 1905), made up of smaller punctures (White 

1976a). However, the head of the Wisconsin specimen is 

clearly more densely punctate with both larger and smaller 

punctures. Both Fall (1905) and White (1975) discussed 

specimens they examined that differed slightly from the 

known species in either punctation or elytral striae, but were 

hesitant to describe them as new species or assign them to 

an already described species until a greater number of specimens was obtained. Until additional specimens and species 

in this genus can be examined, the Wisconsin specimen will 

be considered to represent S. profundus. 

Natural History—Literature to date provides no information as to the hosts or larval food requirements of this species. The only Wisconsin specimen collected during this 

survey was taken from a Lindgren funnel trap in a recently 

burned forest dominated by Pinus strobus Linnaeus and 

Pinus resinosa Aiton. 

Phenology—The adult specimen of S. profundus was collected in Wisconsin during a late April–early May sampling 

interval.

Distribution—The distribution of this species is rather diffuse, from the northwestern states of Washington, Oregon, 

and California, to the northeast from New Jersey, Pennsylvania, and Maryland, and into Indiana (White 1982, 

Philips 2002, Majka 2007a). Stagetus profundus has also 

been recorded in Canada from British Columbia, Ontario, 

Québec (McNamara 1991), and Nova Scotia (Majka 2007a). 

Although specimens of S. profundus have been collected 

most commonly in the northeastern states, in general they 

appear to be rather infrequently encountered (White 1962a). 

The single Wisconsin specimen examined during this study 

represents a NEW STATE RECORD.

Wisconsin Records (Map 56)—The only specimen of 

S. profundus examined during this study was recorded 

from Adams Co. (1): Quincy Bluff TNC.

Genus Striatheca White

Type Species: Striatheca lineata White 1973: 49 (by 

original description and monotypy).

Striatheca White 1973: 48.

Striatheca was established by White (1973): “Striatheca is 

a neo-Latin name of feminine gender formed by taking the 

termination -theca and combining with it stria-, which refers 

to the strongly developed elytral striae.” This genus is said 

to be most closely related to Protheca LeConte, although 

this was prior to the separation of Sculptotheca from Protheca. The characters given for their separation are the form 

of the elytral striae, which are composed of punctures in 
Death-Watch and Spider Beetles of Wisconsin

77

Protheca and Sculptotheca but consist of deeply impressed 

lines in Striatheca, and the form of the anterior process of 

the metathoracic ventrite, which forms a broad lobe in Protheca and Sculptotheca and a hook-like process in Striatheca. The single species, Striatheca lineata, is found in North 

America, north of Mexico. 

The anterior excavation of the metathoracic ventrite, which 

receives the mesothoracic legs in repose, is far less obvious 

than in other Dorcatominae, so that specimens of Striatheca

may potentially be confused with those of Tricorynus. This 

is complicated further by the metathoracic ventrite being 

produced into a narrow, hook-like process in both genera. 

However, careful examination of the ventral surface will 

reveal the metathoracic ventrite to be excavate for the mesothoracic tarsi, especially toward the metasternal process. 

The elytral striation also readily separates these two genera 

in Wisconsin.

Male and female Striatheca are not thought to be easily 

separated. White (1973) stated that there were no external 

sexual characters upon which to separate the sexes.

Striatheca lineata White

(Figs. 219, 220; Map 57)

Striatheca lineata White 1973: 49.

Capsule Description (Figs. 219, 220)—Length: 2.1 mm. 

Width: 1.1 mm. Integument Color: maxillary and labial 

palpi reddish-yellow; antennae orangish; head mostly black, 

suffused with red above mandibles; dorsal surface black; 

scutellum and basal margin of pronotum reddish; margins 

of elytra suffused with red; ventral surface dull reddish, 

suffused with black; tarsi yellowish-orange; surface shining. Body Form: elongate, oval, 1.8X longer than wide.

Vestiture: pubescence yellowish, somewhat sparse, slightly 

denser on pronotal disk, erect on dorsal surface, erect to 

inclined on ventral surface; forming regular rows on either side of elytral striae. Head: antennae 10-segmented, 

clubbed, last 3 segments as long as all preceding, segments 

8 and 9 broadly triangular, 10th segment oval; surface shining with deep, scattered, small to somewhat irregular punctures. Pronotum: subspherical; laterally concave; surface 

shining, punctate, punctures somewhat irregular in size and 

density; laterally crenulate. Elytra: humeri prominent; lateral margins notched for metathoracic legs; with 10 deeply 

impressed striae on each elytron; striae distinct from base to 

apex, not appearing as rows of punctures; surface shining. 

Metathoracic Ventrite: excavate for reception of mesothoracic legs; anteriorly produced in a narrow, hook-like process, concealed by mandibles during body retraction; with 

a moderately impressed, longitudinal sulcus arising from 

anterior carina and extending to apex. Legs: received in 

ventral excavations. Abdomen: with 5 ventrites; 1st ventrite 

grooved for the metathoracic legs.

Diagnosis—Striatheca lineata may be distinguished from 

all other Wisconsin Dorcatominae by a combination of the 

following characters: eyes not incised; prothoracic coxae 

concealed ventrally during body retraction; each elytron 

with 10 distinct striae from base to apex, not appearing as 

rows of punctures (Figs. 219, 220); anterior process of the 

metathoracic ventrite narrow and hook-like; first abdominal 

ventrite grooved for reception of the metathoracic legs 

(extracted in part from Philips 2002).

Natural History—Little has been published on the natural history of S. lineata. This species was described from 

five specimens, taken at various localities at light/UV light 

(White 1973). In Wisconsin, a single specimen was collected in a Lindgren funnel trap baited with ethanol.

Phenology—The single adult specimen of S. lineata was 

recorded from Wisconsin during mid-July.

Distribution—In North America, S. lineata is known only 

from Mississippi, Georgia, and Florida (White 1982). In this 

study, a single specimen was examined from one Wisconsin 

county; it constitutes a NEW STATE RECORD and new 

northwestern range extension of the known distribution for 

the species.

Wisconsin Records (Map 57)—A single specimen was 

examined during this study from the following location: 

Shawano Co. (1): Jung Hemlock–Beech Forest SNA.

Subfamily Mesocoelopodinae

Genera now comprising Mesocoelopodinae were once 

considered members of Dorcatominae (Fall 1905). White 

(1971d) realized Fall’s classification in fact represented two 

separate lineages and proposed the subfamily Tricoryninae 

for Tricorynus Waterhouse, Cryptorama Fall, and Mesocoelopus Jacquelin duVal. He considered Tricoryninae to be 

allied more closely with Xyletininae, whereas Dorcatominae 

was closer to Anobiinae. However, Mesocoelopodinae sensu

Mulsant and Rey (1864) has priority over White’s Tricoryninae (Lawrence and Newton 1995).

Larvae of a number of species in Mesocoelopodinae develop in seeds (White 1982). Other larval food materials 

include dead wood or branches, plant or vine stems, galls, 

as well as a species from apple bark and one from dry kelp 

(White 1982). North American Mesocoelopodinae, north of 

Mexico, includes three genera and 95 species (White 1982, 

1984, Philips 2002), of which only Tricorynus has been recorded from Wisconsin to date.

Members of North American Mesocoelopodinae can be distinguished by having the prothoracic coxae concealed when 

the body is retracted and the metathoracic ventrite without 

tarsal grooves anteriorly on either side of the metasternal 

process (extracted in part from Philips 2002). Species identifications in Mesocoelopodinae can be difficult not only 
General Technical Report FPL–GTR–209

78

due to their small size and compact body structure, but also 

because of the subtle characters used to separate species. 

White (1965, 1984) described species of Tricorynus and 

Cryptorama, both exceedingly specious genera, as markedly 

similar in terms of external morphology. Specimen preparation should ensure that the surface is clear of debris so as 

to expose the surface structure of the cuticle, although even 

when this is done, determinations are often difficult. 

Genus Tricorynus Waterhouse

[Synonymy modified from White 1965, 1982, Philips 2002] 

Type Species: Tricorynus zeae Waterhouse 1849: 68 

(by monotypy). 

Tricorynus Waterhouse 1849: 1xviii.

Catorama Guérin-Méneville 1850: 431.

Hemiptychus LeConte 1865: 239.

Cathorama Gemminger and Harold 1869: 1784 

(emendation).

Xylotheca Reitter 1897: 204.

Hemitychus LeConte; Böving 1954: 297 (lapsus calami).

Tricorynus was described by Waterhouse (1849) for the new 

species, Tricorynus zeae Waterhouse, collected from Barbados Islands (White 1965). The following year, Guérin-Méneville (1850) described the genus Catorama, for Catorama 

tabaci Guérin-Méneville (White 1982). LeConte (1865) 

described five species in the new genus Hemiptychus, transferring two previously described species, Dorcatoma grave

LeConte and Dorcatoma pusillum LeConte, to this genus. 

LeConte and Horn (1883) published a key separating Catorama from Hemiptychus based on the excavation of the 

first ventral segment. Reitter (1897) described Xylotheca for 

one species, Xylotheca meieri Reitter, later synonymized 

with Catorama by Pic (1912a) (White 1965). Fall (1905) 

synonymized Hemiptychus with Catorama and stated that 

members of the genus could be recognized by the 10-segmented antennae and intercoxal hook (Fig. 83) separating 

the mesothoracic coxae. Catorama was finally synonymized 

with Tricorynus by White (1965).

Tricorynus is easily the largest North American genus of 

Ptinidae (White 1974), with 84 species and five subspecies 

in North America, north of Mexico (White 1982). (Tricorynus cryptoglyptus Ford and Tricorynus dudleyae White are 

described later.) This genus is interesting because nearly all 

known species are from the Americas (White 1974). 

Although Tricorynus is a rather large genus, natural history 

of many species is not well known. Most species are known 

to feed in plant seeds, with a few reared from galls (White 

1982, Philips et al. 1998). Other larval food materials include dead limbs and twigs as well as fungi (White 1965). 

One species, Tricorynus herbarius (Gorham), known as the 

Mexican book beetle, is considered the most economically 

significant member of the genus (White 1963), having been 

found to damage historical books, leather, stored foods, 

furniture, and wood (White 1965).

Members of Tricorynus may be distinguished from all other 

Wisconsin Ptinidae by a combination of the following characters: antennae 10-segmented (Fig. 58); prothoracic tibiae 

nearly always striate (Fig. 75); metathoracic ventrite without 

apical, tarsal grooves, and produced into a hook, which the 

beetle is able to grasp between its mandibles when the body 

is contracted (Fig. 83) (extracted in part from Philips 2002). 

White’s (1965) revision of Tricorynus, the last major work 

on this genus in North America, significantly increased our 

understanding of this difficult genus, although he stated, 

“the marked similarities and often minute differences between species are such that any key constructed for their 

separation will require considerable study and effort for effective use.” Punctation of the pronotal and elytral surfaces 

is frequently used in separation of species, a character which 

is impossible to interpret without the proper magnification 

and lighting. The use of a small, hand-held fluorescent light 

significantly enhanced visibility of this feature. Additionally, 

material borrowed from the OSUC, where many of White’s 

type specimens were deposited, was essential for species 

comparisons. Unfortunately, determinations may still be uncertain because it is possible there is more variability within 

species than stated by White (1965). The minute differences 

used by White (1965) for species determinations may actually represent population variation or sibling speciation 

(personal communication T.K. Philips). In fact, one specimen of Tricorynus from Wisconsin was not identified during 

this study because it was unrecognizable to White in 1971, 

even after his work on this genus. This alone suggests future 

work is needed on Tricorynus to evaluate the variability of 

the morphological features; such an analysis would likely 

benefit from molecular analyses. 

The following key includes four species that may be found 

in Wisconsin as they have been recorded from Illinois 

(White 1965). The southwestern species, Tricorynus estriatus (Horn) is also included in the key as four specimens 

were deposited in the IRCW as being collected from Dane 

County, Wisconsin, although as White stated on the determination label, “either label in error or introduced,” and are 

therefore not described further. Many couplets, referring 

to the size and distance between the compound eyes were 

taken directly from White’s (1965) work as there were insufficient Wisconsin specimens available for accurate measurements. Characteristics of the male genitalia, specifically 

internal processes of the median lobe, were said to be diagnostic for species determinations (White 1965) although, 

these characters were not used during this study as separation of males and females based on external morphology is 

generally not possible. 
Death-Watch and Spider Beetles of Wisconsin

79

Key to the Wisconsin Species of Adult Tricorynus

[Modified from White 1962a and 1965]

1 Elytra without distinctly impressed lateral striae on apical half............................................................. estriatus (Horn)

1’ Elytra with 2 distinctly impressed lateral striae on apical half (Figs. 222, 224, 226, 228, 230, 

 232, 234) ......................................................................................................................................................................... 2

2 (1’) Metathoracic ventrite medially with a distinct longitudinal carina (Fig. 83) ................punctatus (LeConte)(p. 82)

2’ Metathoracic ventrite without longitudinal carina medially........................................................................................... 3

3 (2’) Prothoracic tibiae each with only one stria on outer surface .....................................................ventralis (LeConte)

3’ Prothoracic tibiae bisulcate on outer surface (Fig. 75)................................................................................................... 4

4 (3’) Mesothoracic tibiae grooved along posterior margin (Fig. 75) ................................................................................ 5

4’ Mesothoracic tibiae not grooved along posterior margin ............................................................................................. 11

5 (4) Pronotum laterally with small punctures only............................................................................................................ 6

5’ Pronotum laterally with both large and small punctures ................................................................................................ 7

6 (5) Eyes large to moderate, separated by 1.6–2.3X their vertical diameter; lateral raised 

 pronotal margins evident.......................................................................................................... dichrous (Fall)(p. 81)

6’ Eyes very small, separated by 3.1–4.0X their vertical diameter; pronotum lacking lateral 

 raised margin.............................................................................................................................................. densus (Fall)

7 (5’) Large and small pronotal punctures indistinct and sparse; body not gibbous in 

 form; length 1.8–2.0 mm ........................................................................................................ parvus (Fall)(in part)

7’ Large and small pronotal punctures usually distinct, never sparse; form and size variable ........................................... 8

8 (7’) Eyes large to moderate in size, separated by 1.2–2.2X their vertical diameter..................similis (LeConte)(p. 83)

8’ Eyes moderate to small in size, separated by 2.3–2.7X their vertical diameter ............................................................. 9

9 (8’) Large pronotal punctures laterally larger and distinct; surface distinctly shining ........nigritulus (LeConte) (p. 82)

9’ Large pronotal punctures laterally smaller, less distinct; surface rather feebly shining ............................................... 10

10 (9’) Body light reddish-brown; pronotum laterally flat from front to back ................................. parvus (Fall)(in part)

10’ Body usually nearly black, sometimes light reddish-brown; pronotum laterally evenly 

 rounded front to back............................................................................................................................obscurus White

11 (4’) Pubescence of dorsal surface short and sparse, elytral setae separated by more 

 than their length (Figs. 223, 224)............................................................................... castaneus (Hamilton)(p. 80)

11’ Pubescence of dorsal surface normal, elytral setae separated by much less than their length .................................... 12

12(11’) Pronotum laterally with small punctures only, large punctures absent..........................borealis (LeConte)(p. 79)

12’ Pronotum laterally with both large and small punctures distinct ...............................................confusus (Fall)(p. 81)

Tricorynus borealis (LeConte)

(Figs. 221, 222; Map 58)

[Synonymy modified from White 1965] 

Hemiptychus borealis LeConte 1865: 240.

Catorama borealis (LeConte); Fall 1905: 249.

Tricorynus borealis (LeConte); White 1965: 306.

Capsule Description (Figs. 221, 222)—Length: 

2.4–3.0 mm. Width: 0.9–1.8 mm. Integument 

Color: orange-brown to dark reddish-brown throughout; 

maxillary and labial palpi and antennae yellowish-orange to 

brownish-orange. Body Form: elongate, robust, 2.0X longer than wide. Vestiture: pubescence whitish to yellowish, 

moderately dense and mostly recumbent over entire surface. 

Head: terminal segment of each maxillary palpus elongate; 

antennae 10-segmented with 3-segmented club; combined 

length of last 3 antennomeres much longer than length of all 

preceding combined; surface moderately, densely punctate 
General Technical Report FPL–GTR–209

80

with small punctures only. Pronotum: weakly rounded; 

surface densely punctate, with small punctures only. Elytra:

humeri distinct; scutellum small; laterally with 2 distinctly 

impressed striae on apical half, terminating near or before 

level of metathoracic legs; surface moderately, densely 

punctate. Mesothoracic Scutellum: small. Metathoracic 

Ventrite: not grooved anteriorly to receive the mesothoracic 

tarsi, anteriorly produced into a hook-like process (held 

between mandibles in repose); anterior margin at each side 

with usually 1 narrow, elongate fovea; surface moderately, 

densely punctate with larger punctures sometimes sparser 

than small punctures. Legs: mostly received in ventral 

excavations; prothoracic tibiae bisulcate on outer surface; 

mesothoracic tibiae without sulcus along posterior margin of 

outer surface; metathoracic coxae excavate for metathoracic 

femora. Abdomen: with 5 ventrites (appearing as 4); 

1st ventrite excavate for and mostly concealed by 

metathoracic legs.

Diagnosis—Tricorynus borealis may be distinguished from 

all other Wisconsin Tricorynus by the pubescence of dorsal 

surface being not short and sparse (Fig. 221), the pronotum 

laterally with small punctures only, and each mesothoracic 

tibia not grooved along its posterior margin.

Natural History—Little has been published on the natural 

history of this species. In Wisconsin, one specimen was collected in a Lindgren funnel trap. The other two specimens 

had no additional collection data.

Phenology—Adults of T. borealis were recorded in Wisconsin from early to mid-July.

Distribution—Sporadic records of T. borealis are reported 

from Manitoba and Ontario, Canada; in the United States 

from Michigan and Wyoming (White 1982). In this study, 

specimens were examined from two Wisconsin counties; 

they constitute a NEW STATE RECORD. 

Wisconsin Records (Map 58)—The three specimens of 

T. borealis examined during this study were recorded from 

the following localities: Dane Co. (1): Swamp Lover’s Inc.; 

Wood Co. (2): Griffith St. Nursery.

Tricorynus castaneus (Hamilton)

(Figs. 223, 224; Map 59)

[Synonymy modified from White 1965] 

Hemiptychus castaneus Hamilton 1893: 307.

Catorama castaneum (Hamilton); Fall 1905: 247.

Tricorynus castaneus (Hamilton); White 1965: 308.

Capsule Description (Figs. 223, 224)—Length: 1.5–

1.9 mm. Width: 1.0–1.2 mm. Integument Color: light 

yellowish-brown to reddish-brown throughout; maxillary 

and labial palpi and antennae yellowish-orange to brownishorange; surface distinctly shining. Body Form: elongate, 

oval, 1.6X longer than wide. Vestiture: pubescence whitish to yellowish, exceedingly short and sparse on dorsal 

surface, with setae separated by more than their length on 

elytra and pronotum; setae of legs, metathoracic ventrite, 

and abdomen longer and more dense. Head: terminal segment of each maxillary palpus elongate, pointed apically; 

antennae 10-segmented with 3-segmented club; combined 

length of last 3 antennomeres much longer than length of 

all preceding combined; surface sparsely punctate, with 

small punctures only. Pronotum: mostly rounded; surface 

sparsely punctate with small punctures dorsally on disk; 

large, moderately, dense punctures occurring on lateral margins. Elytra: humeri moderately distinct; scutellum very 

small; laterally with 2 distinctly impressed striae on apical 

half, continued to base by shallow, punctate grooves; surface moderately, sparsely punctate. Mesothoracic Scutellum: small. Metathoracic Ventrite: not grooved anteriorly 

to receive the mesothoracic tarsi; anteriorly produced into a 

hook-like process (held between the mandibles in repose); 

anterior margin at each side with a narrow, elongate fovea; 

surface moderately, densely punctate with both large and 

small punctures; large punctures sparse to absent laterally on 

disk. Legs: mostly received in ventral excavations; prothoracic tibiae bisulcate on outer surface; mesothoracic tibiae 

without sulcus on posterior margin of outer surface; metathoracic coxae excavate for metathoracic femora. Abdomen: with 5 ventrites (appearing as 4); 1st ventrite excavate 

for and mostly concealed by metathoracic legs.

Diagnosis—Tricorynus castaneus may be distinguished 

from all other members of Tricorynus by the lack of a sulcus 

on the posterior mesothoracic tibial margin and pubescence 

of dorsal surface exceedingly short and sparse, with elytral 

setae separated by more than the length of a seta (Figs. 223, 

224). 

Natural History—White (1965) reared specimens of T. castaneus from “bullet oak galls formed by the cynipid Disholcaspis quercus globulus (Fitch) on white oak, Quercus alba

(L.).” Specimens have also been reported from “in Virginia 

creeper with Scolytus,” “sweeping grass,” “from oak gall,” 

“beating turkey oak at night,” and “on Vaccinium and other 

low bushes” (White 1965, 1982). In Wisconsin, most specimens were recorded from “gall on oak.” One specimen was 

“from non-wilting Q. macrocarpa.”

Phenology—Adult specimens of T. castaneus were recorded 

in Wisconsin from mid-July to early August.

Distribution—Tricorynus castaneus is mostly known from 

the eastern United States, northeast from Massachusetts, 

west to Indiana and Wisconsin, southeast from Florida, 

southwest as far as Mississippi, Arkansas, and Texas (White 

1977a, 1982). During this study, specimens were recorded 

from two southern Wisconsin counties.

Wisconsin Records (Map 59)—The 12 specimens of T. castaneus examined during this study were recorded from the 

following localities: Kenosha Co. (11): Kenosha; Waukesha Co. (1): no additional locality data.
Death-Watch and Spider Beetles of Wisconsin

81

Tricorynus confusus (Fall)

(Figs. 58, 225, 226; Map 60)

[Synonymy modified from White 1965] 

Catorama confusum Fall 1905: 252.

Tricorynus confusus (Fall); White 1965: 310.

Capsule Description (Figs. 58, 225, 226)—Length: 2.2–

2.4 mm. Width: 1.3–1.4 mm. Integument Color: light to 

dark reddish-brown throughout; maxillary and labial palpi 

and antennae yellowish-orange to brownish-orange. Body 

Form: elongate, oval, 1.8X longer than wide. Vestiture: pubescence whitish to yellowish, moderately dense and mostly 

recumbent over entire surface. Head: terminal segment of 

each maxillary palpus elongate; antennae 10-segmented 

with 3-segmented club; combined length of last 3 antennomeres much longer than length of all preceding combined; 

surface moderately, densely punctate with both large and 

small punctures. Pronotum: distinctly rounded, slightly 

bulging laterally; surface moderately densely punctate, with 

both large and small punctures laterally on disk. Elytra:

humeri distinct; scutellum small; laterally with 2 distinctly 

impressed striae on apical half, terminating near or before 

level of metathoracic legs; surface moderately, densely 

punctate with both large and small punctures. Mesothoracic 

Scutellum: small. Metathoracic Ventrite: not grooved 

anteriorly to receive the mesothoracic tarsi; anteriorly produced into a hook-like process (held between mandibles in 

repose); anterior margin at each side with 2 circular foveae; 

surface moderately, densely punctate with larger punctures 

absent laterally on disk. Legs: mostly received in ventral 

excavations; prothoracic tibiae bisulcate on outer surface; 

mesothoracic tibiae without sulcus along posterior margin of 

outer surface; metathoracic coxae excavate for metathoracic 

femora. Abdomen: with 5 ventrites (appearing as 4); 

1st ventrite excavate for and mostly concealed by 

metathoracic legs.

Diagnosis—Tricorynus confusus may be separated from 

all other Wisconsin Tricorynus by the pubescence of dorsal 

surface being not short and sparse (Fig. 225), the pronotum 

laterally with both large and small punctures, and each 

mesothoracic tibia not grooved along its posterior margin. 

White (1965) described this species with two elongate foveae anteriorly on the metathoracic ventrite, although the Wisconsin specimens examined have two circular, as opposed to 

elongate foveae aneriorly on the disk.

Natural History—White (1982) reported this species, “on 

tree buds and twigs, oak galls, oak, pecan leaves, under 

apple bark, on Quercus imbricaria.” In Wisconsin, one 

specimen was obtained at a Hg vapor lamp and black light 

at night and the other in a Townes–Malaise trap.

Phenology—Adult specimens of T. confusus were recorded 

in Wisconsin from early July to early August.

Distribution—Tricorynus confusus is one of the most widely distributed species in North America (White 1965) and 

has been recorded from the majority of eastern United States 

west to Iowa, Kansas, Oklahoma, and Texas. In this study, 

specimens were examined from two Wisconsin counties; 

they constitute a NEW STATE RECORD.

Wisconsin Records (Map 60)—The two specimens of 

T. confusus examined during this study were recorded from 

the following localities: Dane Co. (1): Swamp Lover’s Inc.; 

Sauk Co. (1): Spring Green Preserve SNA.

Tricorynus dichrous (Fall)

(Figs. 227, 228; Map 61)

[Synonymy modified from White 1965] 

Catorama dichroum Fall 1905: 240.

Tricorynus dichrous (Fall); White 1965: 314.

Capsule Description (Figs. 227, 228)—Length: 2.1–

2.4 mm. Width: 1.1–1.2 mm. Integument Color: ventral 

surface, head, and pronotum orange-brown; metathoracic 

ventrite orange-brown to reddish-brown; elytra darker than 

remainder, reddish-brown to reddish-black; maxillary and 

labial palpi and antennae yellowish-orange to brownishorange. Body Form: elongate, oval, 1.9X longer than wide.

Vestiture: pubescence yellowish; moderately dense and 

mostly recumbent over entire surface. Head: terminal segment of each maxillary palpus elongate; antennae 10-segmented with 3-segmented club; combined length of last 

3 antennomeres much longer than length of all preceding 

combined; surface moderately, densely punctate. Pronotum: mostly rounded; surface moderately, densely punctate, 

laterally with small punctures only. Elytra: humeri distinct; 

scutellum small; laterally with 2 distinctly impressed striae 

on apical half, terminating near or before level of metathoracic legs; surface moderately, densely punctate, with small 

punctures only. Mesothoracic Scutellum: small. Metathoracic Ventrite: not grooved anteriorly to receive the mesothoracic tarsi; anteriorly produced into a hook-like process 

(held between mandibles in repose); surface moderately, 

densely punctate. Legs: mostly received in ventral excavations; prothoracic tibiae bisulcate on outer surface; mesothoracic tibiae with sulcus along posterior margin of outer surface; metathoracic coxae excavate for metathoracic femora. 

Abdomen: with 5 ventrites (appearing as 4); 1st ventrite 

excavate for and mostly concealed by metathoracic legs.

Diagnosis—Tricorynus dichrous may be distinguished from 

all other Wisconsin Tricorynus by the larger compound 

eyes, separated by 1.6–2.3X their vertical diameter; pronotum with small punctures only; elytra with two distinctly 

impressed lateral striae on the apical half (Fig. 228); each 

mesothoracic tibiae with a posterior groove (e.g., Fig. 75).

Natural History—White (1965) examined specimens recorded as “reared form [sic] elm,” and “in tanglefoot on 

w. oak.” White (1969a) mentioned collecting adults during 

the evenings of June 19, 21, and July 8. In Wisconsin, three 

specimens were collected at Lindgren funnel traps and one 
General Technical Report FPL–GTR–209

82

at a flight intercept trap baited with cantharidin (presumably 

incidental and not an attractant).

Phenology—Adult specimens of T. dichrous were recorded 

in Wisconsin from late June to late July.

Distribution—Tricorynus dichrous has been reported from 

much of the eastern United States, from Massachusetts, 

and New York, southeast to South Carolina and Georgia, 

southwest to Mississippi, and northwest into Illinois (White 

1982). In this study, specimens were examined from two 

Wisconsin counties; they constitute a NEW STATE 

RECORD. 

Wisconsin Records (Map 61)—The four specimens of 

T. dichrous examined during this study were recorded from 

the following localities: Adams Co. (3): Quincy Bluff TNC; 

Walworth Co. (1): Kettle Moraine Oak Opening SNA.

Tricorynus nigritulus (LeConte)

(Figs. 229, 230; Map 62)

[Synonymy modified from White 1965] 

Hemiptychus nigritulus LeConte 1865: 240.

Catorama nigritulum (LeConte); Fall 1905: 241.

Tricorynus nigritulus (LeConte); White 1965: 332.

Capsule Description (Figs. 229, 230)—Length: 1.8–

2.2 mm. Width: 1.1–1.2 mm. Integument Color: maxillary 

and labial palpi and antennae yellowish-orange to brownishorange; head, pronotum, and ventral surface black, reddishblack, or reddish; elytra black to black with slight evidence 

of reddish; surface distinctly shining. Body Form: elongate, 

oval, 1.8X longer than wide. Vestiture: pubescence whitish to yellowish, moderately dense and mostly recumbent 

over entire surface. Head: terminal segment of each maxillary palpus elongate, somewhat pointed apically; antennae 

10-segmented with 3-segmented club; combined length of 

last 3 antennomeres much longer than length of all preceding combined; surface moderately, densely punctate. Pronotum: mostly rounded; surface moderately, densely punctate, 

with both large and small punctures laterally. Elytra: humeri distinct; scutellum small; laterally with 2 distinctly impressed striae on apical half, terminating near or before level 

of metathoracic legs; surface moderately, densely punctate. 

Mesothoracic Scutellum: small. Metathoracic Ventrite:

not grooved anteriorly to receive the mesothoracic tarsi; 

anteriorly produced into a hook-like process (held between 

mandibles in repose); anterior margin at each side with 1–

2 narrow, elongate foveae; surface moderately, densely 

punctate with both large and small punctures; large punctures not smaller, or more sparse laterally on disk. Legs:

mostly received in ventral excavations; prothoracic tibiae 

bisulcate on outer surface; mesothoracic tibiae with sulcus 

along posterior margin of outer surface; metathoracic coxae 

excavate for metathoracic femora. Abdomen: with 5 ventrites (appearing as 4); 1st ventrite excavate for and mostly 

concealed by metathoracic legs.

Diagnosis—Tricorynus nigritulus may be distinguished 

from all other Wisconsin Tricorynus by the following 

combination of characters: eyes moderate to small in size, 

separated by 2.3–2.7X their vertical diameter; pronotum laterally with both large and small punctures; elytra with two 

distinctly impressed lateral striae on apical half (Fig. 230); 

prothoracic tibiae bisulcate on outer surface; mesothoracic 

tibiae grooved posteriorly (e.g., Fig. 75); metathoracic ventrite without a longitudinal carina; metathoracic ventrite and 

metepisternum with anterior foveae; entire surface distinctly 

shining. This species most closely resembles T. similis (for 

separation, see diagnosis for T. similis). 

Natural History—White (1965) examined specimens 

“reared from elm.” Other biological records include specimens from vacineae and other low bushes (Hamilton 1893), 

dead wisteria (White 1982), and larvae from the outer wood 

of a debarked elm stump (Hoffman 1940). Böving (1954) 

described larvae of T. nigritulus from specimens collected 

“in wood of Ulmus americana L.,” “ex dead Wisteria,” and 

“in dead Elm branch.” In Wisconsin, most specimens were 

collected using Lindgren funnel traps, two were obtained at 

Townes–Malaise traps, and one from a flight intercept trap. 

Cantharidin was used as bait on one of the Lindgren traps, 

but the association is presummed incidental and the compound is not considered significant in attracting members of 

Tricorynus.

Phenology—Adult specimens of T. nigritulus were recorded 

in Wisconsin from mid-June to mid-August.

Distribution—Tricorynus nigritulus has been recorded from 

much of the eastern United States, northeast from New York 

and Massachusetts, southeast from North Carolina, southwest to Mississippi and Oklahoma, and northwest into Iowa 

(White 1982). In this study, specimens were examined from 

seven Wisconsin counties; they constitute a NEW STATE 

RECORD.

Wisconsin Records (Map 62)—The 13 specimens of 

T. nigritulus examined during this study were recorded from 

the following localities: Dane Co. (6): Swamp Lover’s Inc.; 

Fond du Lac Co. (1): Waupun Park Maple Forest SNA; 

Iowa Co. (1): no other locality data; Lafayette Co. 

(1): Wedel Property– ~3 mi. north of Argyle; Racine Co. 

(2): Private Property–Arango Residence–Greenbriar Road; 

Renak–Polak Maple–Beech Woods SNA; Rock Co: 

(1): Private Property–1.7 mi. NW Janesville; Sauk Co. 

(1): Hemlock Draw TNC.

Tricorynus punctatus (LeConte)

(Figs. 75, 83, 231, 232; Map 63)

[Synonymy modified from White 1965] 

Hemiptychus punctatus LeConte 1865: 240.

Catorama punctatum (LeConte); Fall 1905: 239.

Tricorynus punctatus (LeConte); White 1965: 340.
Death-Watch and Spider Beetles of Wisconsin

83

Capsule Description (Figs. 75, 83, 231, 232)—Length: 

2.1–2.5 mm. Width: 1.1–1.5 mm. Integument Color: uniformly orange-brown to dark reddish-brown; maxillary and 

labial palpi and antennae yellowish-orange to orange-brown. 

Body Form: elongate, oval, 1.8X longer than wide. Vestiture: pubescence yellowish; moderately dense and mostly 

recumbent over entire surface. Head: terminal segment of 

each maxillary palpus elongate, distinctly pointed apically; 

antennae 10-segmented with 3-segmented club; combined 

length of last 3 antennomeres much longer than length of all 

preceding combined; surface moderately, densely punctate. 

Pronotum: mostly rounded, slightly inflated laterally; surface moderately, densely punctate, with both large and small 

punctures laterally. Elytra: humeri distinct; laterally with 

2 distinctly impressed striae on apical half, terminating near 

or before level of metathoracic legs; surface moderately 

densely punctate. Mesothoracic Scutellum: small. Metathoracic Ventrite: not grooved anteriorly to receive the mesothoracic tarsi; anteriorly produced into a hook-like process 

(held between mandibles in repose); medially with a distinct 

longitudinal carina; surface moderately, densely punctate 

with both large and small punctures, large punctures not significantly smaller laterally. Legs: mostly received in ventral 

excavations; prothoracic tibiae bisulcate on outer surface; 

mesothoracic tibiae with sulcus along posterior margin of 

outer surface; metathoracic coxae excavate for metathoracic 

femora. Abdomen: with 5 ventrites (appearing as 4); 

1st ventrite excavate for and mostly concealed by metathoracic legs.

Diagnosis—Tricorynus punctatus may be distinguished 

from all other Wisconsin Tricorynus by the bisulcate prothoracic tibiae (Fig. 75) and distinct carina of the metathoracic 

ventrite (Fig. 83). The sulcus on the posterior margin of the 

mesothoracic tibia is distinct in all but one specimen, causing it to be determined as another species in White’s (1965) 

taxonomic key. As only two species are known to have a 

carina on the metathoracic ventrite, both of which are said 

to have the mesothoracic tibiae sulcate posteriorly, it is clear 

that this specimen is in fact T. punctatus by the bisulcate 

prothoracic tibiae. 

Natural History—White (1965) examined specimens from 

an “old dead sycamore log.” Larvae were described by Böving (1954) from specimens collected “in grape vine.” In 

Wisconsin, single specimens were obtained at a UV light 

and from a Townes–Malaise trap. Five specimens were recorded from flight intercept traps, one of which was baited 

with cantharidin (presumably incidental and not an attractant) and two from Lindgren funnel traps.

Phenology—Adults of T. punctatus were recorded in Wisconsin from early June to late July.

Distribution—Tricorynus punctatus is widely distributed in 

the eastern United States, northeast from New York, southeast to Florida, southwest to Arizona, and northwest to 

Iowa (White 1965, 1982). In this study, specimens were 

examined from six Wisconsin counties; they constitute a 

NEW STATE RECORD.

Wisconsin Records (Map 63)—The 10 specimens of 

T. punctatus examined during this study were recorded from 

the following localities: Dane Co. (1): No additional locality data; Swamp Lover’s Inc.; Dodge Co. (1): W12286 

Hwy 89; Grant Co. (1): Blue River Sand Barrens SNA; 

Green Co. (1): Abraham’s Woods SNA; Lafayette Co. 

(2): Hardscrabble Prairie SNA; Wedel Property– ~3 mi. 

north of Argyle; Rock Co. (1): Private Property–1.7 mi. 

NW Janesville. 

Tricorynus similis (LeConte)

(Figs. 233, 234; Map 64)

[Synonymy modified from White 1965] 

Hemiptychus similis LeConte 1878: 408.

Catorama simile (LeConte); Fall 1905: 250.

Catorama vexatum Fall 1905: 245.

Tricorynus similis (LeConte); White 1965: 343.

Capsule Description (Figs. 233, 234)—Length: 2.1–

2.7 mm. Width: 1.2–1.4 mm. Integument Color: mostly 

reddish-brown; ventral surface orange-brown to reddishbrown; maxillary and labial palpi and antennae yellowishorange to brownish-orange. Body Form: elongate, oval, 

1.8X longer than wide. Vestiture: pubescence whitish to 

yellowish, moderately dense and mostly recumbent over 

entire surface. Head: terminal segment of each maxillary 

palpus elongate; antennae 10-segmented with 3-segmented 

club; combined length of last 3 antennomeres much longer 

than length of all preceding combined; surface moderately, 

densely punctate. Pronotum: mostly rounded; surface 

moderately, densely punctate, with both large and small 

punctures laterally. Elytra: humeri distinct; scutellum small; 

laterally with 2 distinctly impressed striae on apical half, 

terminating near or before level of metathoracic legs; surface moderately, densely punctate, with both large and small 

punctures. Mesothoracic Scutellum: small. Metathoracic 

Ventrite: not grooved anteriorly to receive the mesothoracic 

tarsi; anteriorly produced into a hook-like process (held 

between mandibles in repose); anterior margin at each side 

with 1 narrow, elongate fovea and 1–2 circular foveae. 

Legs: mostly received in ventral excavations; prothoracic 

tibiae bisulcate on outer surface; mesothoracic tibiae with 

sulcus along posterior margin of outer surface; metathoracic 

coxae excavate for metathoracic femora. Abdomen: with 

5 ventrites (appearing as 4); 1st ventrite excavate for and 

mostly concealed by metathoracic legs. 

Diagnosis—Tricorynus similis may be distinguished from 

all other Wisconsin Tricorynus by the following combination of characters: eyes large to moderate in size, separated 

by 1.2–2.2X their vertical diameter; pronotum with both 

large and small punctures; elytra with two distinctly impressed lateral striae on apical half (Fig. 234); mesothoracic 

tibiae grooved posteriorly (e.g., Fig. 75); metathoracic 
General Technical Report FPL–GTR–209

84

ventrite without a longitudinal carina; metathoracic ventrite 

and metepisternum with anterior foveae. 

Relative to the Wisconsin fauna, this species is most similar 

to T. nigritulus, from which it is separated based on the size 

of the compound eyes. White (1965), however, stated this to 

be a seemingly variable character, and determined a number 

of specimens as “nr. nigritulus” based on their larger eyes, 

but did not account for this variation in his key. Based on 

White’s (1965) descriptions, the form of the posterior mesothoracic tibial sulcus may potentially be diagnostic as it 

is thought to be more or less complete in T. nigritulus and 

absent on posterior third in T. similis. The two Wisconsin 

specimens of T. similis examined during this study have the 

apparently larger eyes, but also appear to have a complete 

sulcus on the mesothoracic tibia, and may therefore be more 

similar to what White (1965) considered as “nr. nigritulus.”

Natural History—White (1965) examined specimens of 

T. similis collected “beating oak.” In Wisconsin, one specimen was collected at a Lindgren funnel trap and one in a 

Townes–Malaise trap.

Phenology—Adult specimens of T. similis were recorded in 

Wisconsin from late May to late July.

Distribution—Tricorynus similis is widely distributed in the 

eastern United States northeast from New York, southeast to 

Florida, southwest to Texas and Oklahoma, and northwest 

into Missouri and Illinois (White 1982). In this study, specimens were examined from two, mostly southern Wisconsin 

counties; they constitute a NEW STATE RECORD.

Wisconsin Records (Map 64)—The two specimens of 

T. similis examined during this study were recorded from 

the following localities: Dane Co. (1): Swamp Lover’s Inc.; 

Grant Co. (1): Dewey Heights Prairie SNA–Nelson Dewey 

State Park.

Literature Cited

Aalbu, R.L.; Andrews, F.G. 1992. Revision of the spider 

beetle genus Niptus in North America, including new cave 

and pholeophile species (Coleoptera: Ptinidae). Pan-Pacific 

Entomologist. 68: 73–96.

Acciavatti, R.E. 1972. The ecology of Anobiidae (Coleoptera) associated with northern hardwood forests in central 

New York, with special reference to Ptilinus ruficornis Say. 

New York: State University of New York, College of Environmental Science and Forestry. 131 p. Ph.D. dissertation.

Arango, R.A. 2009. A new species of nearctic Ernobius

Thomson (Coleoptera: Ptinidae: Ernobiinae) from Wisconsin. The Coleopterists Bulletin. 63: 353–356.

Ark, J.T.; Benoit, J.B.; Rellinger, E.J.; Yoder, J.A.; Keeney, 

G.D. 2005. Record 90 day survival without food and water 

by adults of the American spider beetle, Mezium affine. In: 

Proceedings, 25th Midwest Ecology and Evolution Conference. March 11–13. Carbondale, IL. 

Arnett, R.H., Jr. 1983. Checklist of the beetles of North and 

Central America and the West Indies. The click beetles, fireflies, checkered beetles, and related groups. Gainesville, FL: 

Fauna and Fauna Publications. Vol. 4. 214 p.

Ashworth, J.R. 1993. The biology of Lasioderma serricorne. Journal of Stored Products Research. 29: 291–303.

Baker, W.L. 1972. Eastern forest insects. Misc. Pub. 1175. 

Washington, DC: U.S. Department of Agriculture, Forest 

Service. 642 p.

Becker, G. 1951. Bin kaum bekannter Käfer in bauholz 

breite sich aus. Hols. Zbl. 77: 1895–1896. [Abstract]. In: 

Becker, G.; Theden, O., eds. Jahresberichte uber Holzschutz 

1951/52. Berlin: Springer-Verlag. [1954]. 144 p.

Bellés, X. 1994. Stereocaulophilus volcanius gen. n., sp. 

n. (Coleoptera: Ptinidae) from Lanzarote (Canary Islands). 

Elytron. 8: 43–47.

Bellés, X.; Halstead, D.G.H. 1985. Identification and geographical distribution of Gibbium aequinoctiale Boieldieu 

and Gibbium psylloides (Czenpinski) (Coleoptera: Ptinidae). 

Journal of Stored Product Research. 21: 151–155.

Belmain, S.; Simmonds, M.; Ridout, B. 2000. The deathwatch beetle—accommodated in all the best places. Piccadilly, London: The Royal Society of Chemistry. Pesticide 

Outlook. 11: 233–237.

Benoit, J.B.; Yoder, J.A.; Rellinger, E.J.; Ark, J.T.; Keeney, 

G.D. 2005. Prolonged maintenance of water balance by 

adult females of the American spider beetle, Mezium affine

Boieldieu, in the absence of food and water resources. 

Journal of Insect Physiology. 51: 565–573.

Birch, M.C.; Keenlyside, J.J. 1991. Tapping behaviour is a 

rhythmic communication in the deathwatch beetle, Xestobium rufovillosum (Coleoptera: Anobiidae). Journal of Insect 

Behaviour. 4: 257–263.

Blanc, M.P.; Lugon-Moulin, N.; Panighini, C.; Pijnenburg, 

H.; Rossi, L. 2006. Structure of worldwide populations of 

Lasioderma serricorne (Coleoptera: Anobiidae) as revealed 

by amplified fragment length polymorphism profiles. Bulletin of Entomological Research. 96: 111–116.

Borowski, J.; Zahradník, P. 2007. Ptinidae. In: Löbl, I.; 

Smetana, A., eds. Catalogue of palaearctic coleopteran. 

Stenstrup, Denmark: Apollo Books. Vol. 4: 328–362.

Böving, A.G. 1954. Mature larvae of the beetle family 

Anobiidae. Det Kongelige Danske Videnskabernes Selskab 

Biologiske Meddelelser. 22: 1–298.

Brown, W.J. 1959. Niptus Boield. and allied genera in North 

America (Coleoptera: Ptinidae). The Canadian Entomologist. 91: 627–633.

Cabrera, B.J. 2001. Drugstore beetle, Stegobium paniceum

(L.) (Insecta: Coleoptera: Anobiidae). http://edis.ifas.ufl.edu/

in385. (Date accessed 24 October 2011).
Death-Watch and Spider Beetles of Wisconsin

85

Cabrera, B.J.; Marsh, P.M.; Lewis, V.R.; Seybold, S.J. 2002. 

A new species of Heterospilus (Hymenoptera: Braconidae) 

associated with the deathwatch beetle, Hemicoelus gibbicollis (LeConte) (Coleoptera: Anobiidae). Pan-Pacific Entomologist. 78: 7–16.

Casey, T.L. 1898. Studies in the Ptinidae, Cioidae and 

Sphindidae of America. Journal of the New York 

Entomological Society. 6: 61–93.

Champlain, A.B.; Knull, J.N. 1922. Miscellaneous notes 

on Coleoptera. The Canadian Entomologist. 54: 102–104.

Coffelt, J.A.; Vick, K.W. 1973. A black mutation of Lasioderma serricorne (F.) (Coleoptera: Anobiidae). Journal of 

Stored Products Research. 9: 65–70.

Colwell, R.K. 1996. BIOTA: The biodiversity database 

manager [software book XXV]. Sunderland, MA: Sinauer 

Associates. 574 p.

Craighead, F.C. 1950. Insect enemies of eastern forests. 

Misc. Pub. 657. Washington, DC: U.S. Department of 

Agriculture, Forest Service. 679 p.

Crowson, R.A. 1955. The natural classification of the 

families of Coleoptera. London: Nathaniel Lloyd & Co., 

Ltd. 187 p.

Crowson, R.A. 1955. [reprinted 1967]. The natural classification of the families of Coleoptera. England: E.W. Classey, 

Ltd. 214 p.

Crowson, R.A. 1981. The biology of the Coleoptera. 

London: Academic Press. 802 p.

Davis, W.T.; Leng, C.W. 1912. Insects on a recently felled 

tree. Journal of the New York Entomological Society. 

20: 119–121.

Downie, N.M.; Arnett, R.H. 1996. The beetles of northeastern North America. Polyphaga: Series Bostrichiformia 

through Curculionoidea. Gainesville, FL: The Sandhill 

Crane Press. 891–1721. Vol. II.

Ebeling, W. 1978. Urban entomology. Berkeley, CA: University of California, Agricultural Sciences Publications. 

695 p.

Español, F. 1973. Notas sobre Anobidos. Miscelanea 

Zoologica. 3: 51–67.

Español, F. 1992. Coleoptera, Anobiidae. In: Ramos, M.A., 

et al. (eds.). Fauna Ibérica, Museo Nacional de Ciencias Naturales. Madrid, Spain: Consejo Superior de Investigaciones 

Científicas. 195 p. Vol. 2.

Fabricius, J.C. 1792. Entomologia systematica emendata et 

aucta. Secundum classes, ordines, genera, species adjectis 

synonimis, locis, observationibus, descriptionibus. Hafniae. 

1: 1–330.

Fall, H.C. 1905. Revision of the Ptinidae of Boreal America. 

Transactions, American Entomological Society. 31: 97–296.

Farnham, A.S.; Flora, J.W.; Ingram, S.S.; Faustini, D.L. 

2007. No evidence of substantial nicotine metabolism by 

Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae) 

reared on tobacco. Journal of Stored Products Research. 43: 

171–176.

Felt, E.P. 1905. Insects affecting park and woodland trees. 

Memoir 8. New York: State Museum. 877 p. Vol. 1.

Ferro, M.L.; Gimmel, M.L.; Carlton, C.E. 2007. Fine 

beetles: The community structure of Coleoptera in twigs and 

the efficacy of using twig bundles as a collecting technique 

[Abstract]. Abstract D0035. In: Entomological Society of 

America annual meeting. San Diego, CA: December 9–12.

Fisher, R.C. 1940. Studies of the biology of the deathwatch 

beetle, Xestobium rufovillosum de Geer. Part III. Fungal decay in timber in relation to the occurrence and rate of development of the insect. Annals of Applied Biology. 

27: 545–557.

Fleming, J. 1821. Insecta. In: Constable, A., ed. Supplement 

to the fourth, fifth, and sixth editions of the Encyclopedia 

Britannica. Edinburgh: 41–56, pl. 85. Vol. 5.

Ford, E.J. 1973. A revision of the genus Petalium LeConte 

in the United States, Greater Antilles, and the Bahamas 

(Coleoptera: Anobiidae). Tech. Bull. 1467. Washington, DC: 

U.S. Department of Agriculture, Agricultural Research Service. 40 p.

Ford, E.J. 1984. Priobium carpini (Herbst), an old world 

anobiid now established in Maryland (Coleoptera). The 

Coleopterists Bulletin. 38: 249–250.

Ford, E.J. 1998. Two new species of North American anobiid beetles, with notes on the sexes of Stagetus grossus

White (Coleoptera: Anobiidae). The Coleopterists Bulletin. 

52: 150–154.

Frost, S.W. 1975. Third supplement to insects taken in light 

traps at the Archbold Biological Station, Highlands County, 

Florida. The Florida Entomologist. 58: 35–42.

Furniss, R.L. 1939. Insects attacking forest products and 

shade trees in Washington and Oregon in 1937. Proceedings, 

Entomological Society of British Columbia. 33: 5–8.

Geoffroy, E.L. 1762. Histoire abregee des insectes qui se 

trouvent aux environs de Paris; dans laquelle ces animaux 

sont ranges suivant un ordre methodique. Paris: Durand. 

523 p. Vol. 1.

Gilberg, M. 1989. Inert atmosphere fumigation of museum 

objects. Studies in Conservation. 34: 80–84.

Gistel, J. 1856. Die Mysterien der Europäischen Insectenwelt. Dannheimer, T., ed. Germany: Kempten. 530 p.

Goulson, D.; Birch, M.C.; Wyatt, T.D. 1994. Mate location 

in the deathwatch beetle, Xestobium rufovillosum De Geer 
General Technical Report FPL–GTR–209

86

(Anobiidae): orientation to substrate vibrations. Animal 

Behavior. 47: 899–907.

Grimaldi, D.; Engel, M.S. 2005. Evolution of insects. 

New York: Cambridge University Press. 755 p.

Guérin-Méneville, F.E. 1850. Enumeration des insectes qui 

consomment les tabacs et description du Catorama tabaci. 

Revue et Magasin de Zoologie. 2: 426–442.

Gunasekaran, N.; Rajendran, S. 2005. Toxicity of carbon dioxide to drugstore beetle Stegobium paniceum and cigarette 

beetle Lasioderma serricorne. Journal of Stored Products 

Research. 41: 283–294.

Halstead, D.G.H. 1986. Keys for the identification of beetles 

associated with stored products. Introduction and key to 

families. Journal of Stored Products Research. 22: 163–203.

Hamilton, J. 1893. Descriptions of some species of Coleoptera occurring near Allegheny, heretofore undescribed. 

Canadian Entomologist. 25: 305–310.

Harrington, W.H. 1887. Insects infesting maple trees. Annual report, Entomological Society of Ontario. 17: 22–33.

Harrington, W.H. 1897. Some beetles occurring upon 

beech. Annual report, Entomological Society of Ontario. 

27: 69–75.

Hatch, M.H. 1961. The beetles of the Pacific Northwest. 

Part III: Pselaphidae and Diversicornia I. Seattle, WA: University of Washington, Biology Publication. 16: 1–503.

Hedges, S.A.; Lacey, M.S. 1996. Field guide for the management of structure-infesting beetles. In: Moreland, D., ed.; 

Stvan, J., ill. Stored product beetles/occasional & overwintering beetles. Cleveland, OH: G.I.E., Inc. 212 p. Vol. II.

Herbst, J.F.W. 1792. Natursystem aller bekannten in- und 

auslaendischen Insekten, als eine Fortsetzung der von Bueffonschen Naturgeschichte. Berlin: Pauli. 197 p. Vol. 4.

Hinton, H.E. 1941. The Ptinidae of economic importance. 

Bulletin of Entomological Research. 31: 331–381.

Hoffman, C.H. 1940. Additions to annotated lists of insects 

reared from elm bark and wood. Bulletin of the Brooklyn 

Entomological Society. 35: 54–63.

Hopkins, A.D. 1893. Catalogue of West Virginia forest and 

shade tree insects. West Virginia: Agricultural Experimental 

Station Bulletin. 32: 171–251.

Hori, M. 2004. Repellency of hinokitiol against the cigarette 

beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae). Applied Entomology and Zoology. 39: 521–526.

Howe, R.W. 1940. New records of insects in grain stores. 

The Entomologist’s Monthly Magazine. 76: 73–75.

Howe, R.W. 1953. Studies on beetles of the family Ptinidae: 

VIII. The intrinsic rate of increase of some Ptinid beetles. 

Annals of Applied Biology. 40: 121–133.

Howe, R.W. 1957. A laboratory study of the cigarette beetle, 

Lasioderma serricorne (F.) (Col., Anobiidae) with a critical 

review of the literature on its biology. Bulletin of Entomological Research. 48: 9–56.

Imai, T.; Harada, H. 2006. Low-temperature as an alternative to fumigation to disinfest stored tobacco of the cigarette 

beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae). 

Applied Entomology and Zoology. 41: 87–91.

Ivie, M.A. 1985. Phylogenetic studies in the Bostrichiformia 

(Coleoptera). Columbus, OH: Ohio State University. 137 p. 

Ph.D. dissertation.

Jacobs, J.M.; Spence, J.R.; Langor, D.W. 2007. Influence of 

boreal forest succession and dead wood qualities on saproxylic beetles. Agriculture and Forest Entomology. 9: 3–16.

Johnson, C. 1975. A review of the palearctic species of 

the genus Ernobius Thomson. Entomologische Blätter. 

71: 65–93.

Johnson, C.W. 1921. A new ptinid for New England. 

Psyche. 28: 7.

Jonsell, M.; Nordlander, G.; Jonsson, M. 1999. Colonization 

patterns of insects breeding in wood-decaying fungi. Journal 

of Insect Conservation. 3: 145–161.

Jonsson, M.; Oskar, K.; Jonsell, M.; Nordlander, G. 2003. 

Modelling mating success of saproxylic beetles in relation 

to search behavior, population density and substrate abundance. Animal Behaviour. 65: 1069–1076.

Karawaiew, W. 1899. Über anatomie und metamorphosis 

des darmkanals der larve von Anobium paniceum. Biologisches Zentralblatt. 19: 122–130, 161–171, 196–220.

Knutson, L.V. 1963. Revision of the genus Hadrobregmus

of North America (Coleoptera: Anobiidae). Proceedings, 

Entomological Society of Washington. Washington, DC: 

U.S. Department of Agriculture, Agriculture Research Service. 65: 177–195.

Kuwahara, Y.; Fukami, H.; Howard, R.; Ishii, S.; Matsumura, F.; Burkholder, W.E. 1978. Chemical studies on the Anobiidae: sex pheromone of the drugstore beetle, Stegobium 

paniceum (L.) (Coleoptera). Tetrahedron. 34: 1769–1774.

Kuwahara, Y.; Fukami, H.; Ishii, S.; Matsumura, F.; Burkholder, W.E. 1975. Studies on the isolation and bioassay of 

the sex pheromone of the drugstore beetle, Stegobium paniceum (Coleoptera: Anobiidae). Journal of Chemical Ecology. 1: 413–422.

Kyhl, J.F.; Seybold, S.J. 2002. Yard & garden brief: powderpost and other wood-destroying beetles in Minnesota structures. Minneapolis, MN: University of Minnesota Extension 

Service. http://www.extension.umn.edu/yardandgarden/

ygbriefs/e609powderpost.html. (Date accessed 24 October 

2011).
Death-Watch and Spider Beetles of Wisconsin

87

Latreille, P.A. 1802. Histoire Naturelle, Générale et Particuliére des Crustacés et des Insectes. In: Dufart, F., ed. 

Familles Naturelles des Genres. Paris: 387 p. Vol. 3.

Latreille, P.A. 1809. Genera crustaceorum et insectorum 

secundum ordinem naturalem in familias disposita, iconibus 

exemplisque plurimis explicata. Paris: Koenig. 399 p. Vol. 4.

Latreille, P.A. 1810. Considerations generales sur l’ordre 

naturel des animaux composant les classes des crustaces, 

des arachnides, et des insectes; avec un tableau methodique 

de leurs genres, disposes en familles. Paris: Schoell. 444 p.

Lawrence, J.F.; Newton, A.F. 1995. Families and subfamilies of Coleoptera (with selected genera, notes, references 

and data on family group names). In: Pakaluk, J.; Slipinski, 

S.A., eds. Biology, phylogeny and classification of Coleoptera. Papers celebrating the 80th birthday of Roy A. Crowson. Warszawa, Poland: Muzeum i Instytut Zoologii PAN. 

779–1006. Vol. 2.

LeConte, J.L. 1861. Classification of the Coleoptera of 

North America. Prepared for the Smithsonian Institution. 

Part I. Washington, DC: Smithsonian Miscellaneous 

Collection. 3: 1–208.

LeConte, J.L. 1865. Prodromus of a monograph of the species of the tribe Anobiini, of the family Ptinidae, inhabiting 

North America. Proceedings, Academy of Natural Sciences 

of Philadelphia. 17: 222–236.

LeConte, J.L. 1874. Appendix, p. 272–276. In: Austin, 

E.P.; LeConte, J.L., eds. Catalogue of the Coleoptera of Mt. 

Washington, N.H.; with descriptions of new species. Proceedings, Boston Society of Natural History. 16: 265–276. 

[Descriptions of new species by LeConte.]

LeConte, J.L. 1878. Descriptions of new species. In: Hubbard, H.G.; Schwarz, E.A. The Coleoptera of Michigan. 

Proceedings, American Philosophical Society. 17: 593–626.

LeConte, J.L.; Horn, G.H. 1883. Classification of the Coleoptera of North America. Washington, DC: Smithsonian 

Miscellaneous Collection. 507: 1–567.

Lefkovitch, L.P. 1963. Census studies on unrestricted populations of Lasioderma serricorne (F.) (Coleoptera: Anobiidae). Journal of Animal Ecology. 32: 221–231.

Leng, C.W. 1920. Catalogue of the Coleoptera of America, 

north of Mexico. Sherman, J.D., Jr., ed. Mount Vernon, NY: 

470 p.

Leng, C.W. 1928. Order Coleoptera. In: Leonard, M.D., ed. 

A list of the insects of New York. New York: Cornell Agricultural Experiment Station Memoir. 101: 203–520.

Levinson, H.; Levinson, A. 1994. Origin of grain storage 

and insect species consuming desiccated food. Journal of 

Pest Science. 67: 47–60.

Levinson, H.Z.; Levinson, A.R.; Francke, W.; Machenroth, 

W.; Heeman, V. 1981. The pheromone activity of anhydroserricornin and serricornin for male cigarette beetles Lasioderma serricorne (F.). Naturwissenschaften. 68: 148–149.

Lindhe, A.; Lindelöw, A.; Asenblad, N. 2005. Saproxylic 

beetles in standing dead wood density in relation to substrate sun-exposure and diameter. Biodiversity and Conservation. 14: 3033–3053.

Linsley, E.G. 1943. The recognition and control of deathwatch, powderpost, and false powderpost beetles. Pests. 

11: 11–14.

Linsley, E.G.; MacSwaine, J.W. 1942. The bionomics of 

Ptinus californicus, a depredator in the nests of bees. Bulletin of the Society of the California Academy of Science. 

40: 126–137.

Mahroof, R.M.; Phillips, T.W. 2008. Responses of storedproduct Anobiidae to pheromone lures and plant-derived 

volatiles. Journal of Applied Entomology. 132: 161–167.

Majka, C.G. 2007a. The Derodontidae, Dermestidae, Bostrichidae, and Anobiidae of the maritime provinces of Canada (Coleoptera: Bostrichiformia). Zootaxa. 1573: 1–38.

Majka, C.G. 2007b. The Eucnemidae (Coleoptera) of the 

maritime provinces of Canada: new records, observations on 

composition and zoogeography, and comments on the rarity 

of saproxylic beetles. Zootaxa. 1636: 33–46.

Mallis, A. 1960. Handbook of pest control: the behavior, life 

history, and control of household pests. New York: MacNair–Dorland Co. 1,132 p.

McNamara, J. 1991. Family Anobiidae: deathwatch beetles. 

In: Bousquet, Y., ed. Checklist of beetles of Canada and 

Alaska. E. Ottawa, Ontario: Agriculture Canada Publication. 

1861: 201–205.

Melsheimer, F.E. 1845. Descriptions of new species of 

Coleoptera of the United States. Proceedings, Academy of 

Natural Sciences of Philadelphia. 2: 302–318.

Moore, H.B. 1964. Observations on the biology of Xyletinus peltatus (Harris) (Coleoptera: Anobiidae) with notes on 

morphology. Raleigh, NC: North Carolina State University. 

71 p. Ph.D. dissertation.

Moore, H.B. 1979. Wood-inhabiting insects in houses: their 

identification, biology, prevention and control. Prepared as 

part of interagency agreement IAA–25–75. Washington, 

DC: U.S. Department of Agriculture, Forest Service, and 

Department of Housing and Urban Development. 133 p.

Mueller, O.F. 1764. Fauna insectorum Friedrichsdalina, sive 

methodica descriptio insectorum agri Fridrichsdalensis, cum 

characteribus genericis et specificis, nominibus trivialibus, 

locis natalibus, iconibus allegatis, novisque pluribus speciebus additis. Hafniae et Lipsiae. 96 p.

Mulsant, E.; Rey, C. 1864. Histoire naturelle des coleopteres 

de France. Paris: Térédiles, Savy. 391 p.
General Technical Report FPL–GTR–209

88

Ngamo, T.S.L.; Ngassoum, M.B.; Mapongmestsem, P.M.; 

Noudjou, W.F.; Malaisse, F.; Haubruge, E.; Lognay, G.; 

Kouninki, H.; Hance, T. 2007. Use of essential oils of aromatic plants as protectant of grains during storage. Agricultural Journal. 2: 204–209.

Novoa, F.; Baselga, A. 2000. A new species of Ernobius

Thomson (Coleoptera: Anobiidae: Ernobiinae) from the Cíes 

Islands, Spain. The Coleopterists Bulletin. 54: 403–407.

Packard, A.S. 1890. Fifth report of the United States Entomological Commission, being a revised and enlarged edition 

of Bulletin No. 7, on insects injurious to forest and shade 

trees. 5th report, U.S. Entomological Commission. Washington, DC: U.S. Department of Agriculture. 957 p.

Pant, N.C.; Fraenkel, G. 1954. Studies on the symbiotic 

yeasts of two insect species, Lasioderma serricorne F. and 

Stegobium paniceum L. Biological Bulletin. 107: 420–432.

Papadopoulou, S.C.; Buchelos, C.T. 2002. Identification of 

female adult Lasioderma serricorne (F.) by simple external 

observation of the abdomen. Journal of Stored Products 

Research. 38: 315–318.

Papp, C.S. 1962. Ptinidae of North America. Deutsche 

Entomologische Zeitschrift, N.F. 9: 367–423. 

Paykull, G. von. 1798. Fauna Suecica, Insecta. Upsaliae. 

358 p.

Pellitteri, P.J. 1977. Faunistic survey of stored product insects found in southern Wisconsin feed mills. Madison, WI: 

University of Wisconsin. 131 p. Master’s thesis.

Pellitteri, P.J.; Boush, G.M. 1983. Stored-product insect 

pests in feed mills in southern Wisconsin. Wisconsin Academy of Sciences, Arts and Letters. 71: 103–112.

Perry, A.S.; Buckner, A.J. 1959. The metabolic fate of prolan in a dilan-resistant strain of house flies. Journal of Economic Entomology. 52: 997–1002.

Philips, T.K. 2000. Phylogenetic analysis of the New World 

Ptininae (Coleoptera: Bostrichoidea). Systematic Entomology. 25: 235–262.

Philips, T.K. 2002. Family 70: Anobiidae. In: Arnett, R.H., 

Jr.; Thomas, M.C.; Skelley, P.E.; Frank, J.H., eds. American 

Beetles. Boca Raton, FL: CRC Press. 245–260. Vol. 2.

Philips, T.K.; Ivie, M.A.; Ivie, L.L. 1998. Leaf mining and 

grazing in spider beetles (Coleoptera: Anobiidae: Ptininae): an unreported mode of larval and adult feeding in 

the Bostrichoidea. Proceedings, Entomological Society of 

Washington. 100: 147–153.

Pic, M. 1903. Sur les genres “Micranobium” Gorham et 

“Rhadine” Baudi. Echange. 19: 171–172.

Pic, M. 1912a. Pars 48. Anobiidae. In: Schenkling, S., ed. 

Coleopterorum Catalogus. Berlin: W. Junk. 10: 1–92.

Pic, M. 1912b. Quelques mots sur la classification des Anobiides. L’Echange, Revue Linneenne. 28: 47–48.

Powell, T.E. 1931. An ecological study of the tobacco beetle, Lasioderma serricorne Fabr., with special references to 

its life history and control. Ecological Monographs. 

1: 333–393.

Quinn, M.A. 2000. Abundance and distribution of potential 

arthropod prey species in a typical golden-cheeked warbler 

habitat. College Station, TX: Texas A&M University. 182 p. 

Master’s thesis.

Radinovsky, S. 1957. The biology of Ptinus villiger (Reit.). 

Winnipeg, Manitoba, Canada: University of Manitoba. 62 p. 

Master’s thesis.

Ramírez, J.L.; Santana, M.A.; Galindo-Castro, I.; Gonzalez, A. 2005. The role of biotechnology in art preservation. 

Trends in Biotechnology. 23: 584–588.

Redtenbacher, L. 1849. Fauna Austriaca. Die Kaefer. Nach 

der analytischen Methode bearbeitet. Wien: Carl Gerold. 

883 p.

Rees, D. 2004. Insects of stored products. Australia: Csiro 

Publishing. 181 p.

Reitter, E. 1877. Beitraege sur Kaeferfauna von Japan. 

(Drittes Stueck.). Deutsche Entomologische Zeitschrift. 

21: 369–384.

Reitter, E. 1897. Zehnter Beitrag zur Coleopteren-Fauna von 

Europa und den angrenzenden Laendern. Wiener Entomologische Zeitung. 16: 203–206.

Rozen, J.G., Jr. 1957. Biological notes on Eucrada humeralis (Melsheimer) (Anobiidae). The Coleopterists Bulletin. 

XI: 53–54.

Ruckes, H., Jr. 1957. A synopsis of the California deathwatch beetles of the genus Ernobius Thomson, with descriptions of two new species which attack pine cones. The PanPacific Entomologist. 33: 157–161.

Runner, G.A. 1919. The tobacco beetle: an important pest in 

tobacco products. Agric. Bull. 737. Washington, DC: U.S. 

Department of Agriculture. 77 p.

Say, T. 1825. Descriptions of new species of coleopterous 

insects inhabiting the United States. Journal of the Academy 

of Natural Sciences of Philadelphia. 5: 160–204.

Schooley, H.O. 1983. A deathwatch cone beetle (Anobiidae: Ernobius bicolor) reduces the natural storage of black 

spruce seed in Newfoundland. The Forestry Chronicle. 

59: 139–142.

Schwemmler, W. 1989. Insect endocytobiosis: morphology, 

physiology, genetics, evolution. In: Schwemmler, W.; Gassner, G., eds. Boca Raton, FL: CRC Press, Inc. 272 p.
Death-Watch and Spider Beetles of Wisconsin

89

Seidlitz, G.von. 1889. See Seidlitz, G. von (1891).

Seidlitz, G. von, 1891. Fauna Baltica. Die Kaefer (Coleoptera) der deutschen Ostseeprovinzen Russlands. 2nd ed. 

(1887–1891). Koenigsberg: Familien LVI, Gattungen 

192 and Arten. 818 p.

Seybold, S.J. 2001. Scientific note: a new and unusual host 

record for Hemicoelus gibbicollis (LeConte) (Coleoptera: 

Anobiidae). Pan-Pacific Entomologist. 77: 123–125.

Shuckard, W.E. 1840. The British Coleoptera delineated, 

consisting of figures of all the genera of British beetles, 

drawn in outline by W. Spry, M.E.S. London: W. Crofts. 

vii + 83 p., 86 + 8 pls.

Simeone, J.B. 1960. Observations on Hadrobregmus carinatus (Say) and other wood-feeding Anobiidae (Coleoptera) in 

the northeastern United States. Ithaca, NY: Cornell University. 183 p. Ph.D. dissertation.

Simeone, J.B. 1961. An introduced species of Ptilinus from 

New York (Coleoptera: Anobiidae). The Canadian Entomologist. 43: 428–430.

Smith, E.H.; Whitman, R.C. 1992. NPMA field guide to 

structural pests. Fairfax, VA: National Pest Management 

Association, Inc. 800 p.

Spilman, T.J. 1975. Ptinidae, Anobiidae. In: Blackwelder, 

R.E.; Arnett, R.H., Jr., eds. Checklist of the beetles of Canada, United States, Mexico, Central America, and the West 

Indies. Vol. 1(5): The darkling beetles, ladybird beetles and 

related groups (red version). Rensselaerville, NY: Biological 

Research Institute of America. 

Spilman, T.J. 1991. Insects & mite pests in food, an illustrated key. Spider beetles (Ptinidae, Coleoptera). 1: 137–147.

Stephens, J.F. 1829. A systematic catalogue of British insects: being an attempt to arrange all the hitherto discovered 

indigenous insects in accordance with their natural affinities. 

Containing also the references to every English writer on 

entomology, and to the principal foreign authors. With all 

the published British genera to the present time. London: 

Baldwin and Cradock. 388 p.

Stephens, J.F. 1835. Illustrations of British entomology, or, 

a synopsis of indigenous insects: containing their generic 

and specific distinctions; with an account of their metamorphoses, times of appearance, localities, food, and economy, 

as far as practicable. Mandibulata. London: Baldwin and 

Cradock. 5: 369–447.

Suomi, D.A.; Akre, R.D. 1992. Characteristics of structures 

attacked by the wood-infesting beetle, Hemicoelus 

gibbicollis (Coleoptera: Anobiidae). Journal of the Entomological Society of British Columbia. 89: 63–70.

Swingle, M.C. 1938. Low temperature as a possible means 

of controlling the cigarette beetle in stored tobacco. Agric. 

Circ. 462. Washington, DC: U.S. Department of Agriculture. 

8 p.

Thomson, C.G. 1859. Skandinaviens Coleoptera, synoptiskt 

bearbetade. Lund. 1: 290 p.

U.S. Department of Agriculture. 1971. Stored tobacco insects, biology and control. Agric. Handb. 233. Washington, 

DC: Stored Product Insects Research Branch, Market Quality Research Division, Agricultural Research Service. 12 p.

VanRyckeghem, A. 2004. Stored product pests. In: Mallis, 

A., ed. Mallis handbook of pest control: the behavior, life 

history, and control of household pests. 9th ed. Hedges, 

S.A.; Moreland, D.; Angus, K., eds. Richfield, OH: GIE 

Media. 1397 p., 746–823. Chapter 13.

Viitanen, H. 2001. Biodegradation of cultural heritage, State 

of the Art, Finland. ARIADNE Proceedings: Prague, 8 pp.

Waterhouse, G.R. 1849. Descriptions of two beetles from 

Barbados. Proceedings, Entomological Society of London. 

1xviii–1xx. 

Weiss, H.B. 1922. Notes on the puffball beetle, Caenocara 

oculata (Say). Psyche. 29: 92–94.

Weiss, H.B.; West, E. 1922. Notes on fungous insects. 

Canadian Entomologist. 54: 198–199.

White, R.E. 1960. Four new eastern species of drug-store 

and death-watch beetles (Coleoptera: Anobiidae). Ohio 

Journal of Science. 60: 235–238.

White, R.E. 1962a. The Anobiidae of Ohio (Coleoptera). 

Bulletin of the Ohio Biological Survey (new series). 

1: 1–58.

White, R.E. 1962b. A new Xyletinus, with a key to the North 

American species (Coleoptera: Anobiidae). Annals of the 

Entomological Society of America. 55: 251–253.

White, R.E. 1963. The Mexican book beetle, Catorama herbarium, established in the United States (Coleoptera: Anobiidae). Annals of the Entomological Society of America. 

56: 280–285.

White, R.E. 1965. Taxonomic and distribution notes on 

Anobiidae (Coleoptera). The Coleopterists Bulletin. 

19: 113–116.

White, R.E. 1966a. Six new Anobiidae from North America 

with keys. Proceedings, Entomological Society of Washington. 68: 228–236.

White, R.E. 1966b. Cryptoramorphus floridanus, new 

genus, new species (Coleoptera: Anobiidae), with generic 

reassignments. Annals of the Entomological Society of 

America. 59: 959–961.

White, R.E. 1969a. Field note: an unusual concentration of 

Anobiidae. The Coleopterists Bulletin. 23: 102, 107.

White, R.E. 1969b. Xyletinus Latreille, 1809, and Lasioderma Stephens, 1835 (Insecta, Coleoptera: Anobiidae): 

proposed designation of a type-species under the plenary 

powers to avoid synonymy. Bulletin of Zoological Nomenclature. 26: 57–58.
General Technical Report FPL–GTR–209

90

White, R.E. 1969c. Taxonomic notes on North American 

Anobiidae (Coleoptera). Entomological News. 80: 252–258.

White, R.E. 1970. Ptilinus serricollis Say, a forgotten name. 

Proceedings, Entomological Society of Washington. 

72: 414.

White, R.E. 1971a. Key to North American genera of Anobiidae, with phylogenetic and synonymic notes (Coleoptera). Annals of the Entomological Society of America. 

64: 179–191.

White, R.E. 1971b. The Status of Lasioderma castaneum

Melsheimer and Dorcatoma affinis Boheman. Proceedings, 

Entomological Society of Washington. 73: 213–215.

White, R.E. 1971c. New generic synonymy and new combinations in Anobiidae. Proceedings, Entomological Society 

of Washington. 73: 341–343.

White, R.E. 1971d. A new subfamily in Anobiidae (Coleoptera). Annals of the Entomological Society of America. 

64: 1301–1304.

White, R.E. 1973. A new genus, two new species, and a species key for Byrrhodes. Proceedings, Entomological Society 

of Washington. 75: 48–54.

White, R.E. 1974. Type-species for world genera of Anobiidae (Coleoptera). Transactions, American Entomological 

Society. (1973)99: 415–475.

White, R.E. 1975. Sixteen new neotropical Anobiidae with a 

new genus and keys (Coleoptera). Proceedings, Entomological Society of Washington. 77: 169–188.

White, R.E. 1976a. A new genus and four new species of 

North American Anobiidae with notes. The Coleopterists 

Bulletin. 30: 337–342.

White, R.E. 1976b. Eight new North American species of 

Anobiidae with keys and notes (Coleoptera). Proceedings, 

Entomological Society of Washington. 78: 154–170.

White, R.E. 1977a. Note: new state records for species of 

Tricorynus (Anobiidae: Coleoptera). Proceedings, Entomological Society of Washington. 79: 37.

White, R.E. 1977b. Ten new North American species of Xyletinus (Anobiidae: Coleoptera). Proceedings, Entomological Society of Washington. 79: 521–537.

White, R.E. 1979. The genus Protheca of the Americas 

(Coleoptera: Anobiidae). Tech. Bull. 1605. Washington, 

DC: U.S. Department of Agriculture. 24 p.

White, R.E. 1980. Review of Vrilletta, with two new species 

and a key (Coleoptera: Anobiidae). Journal of the Washington Academy of Science. 70: 144–148.

White, R.E. 1981. Three new species of Anobiidae from 

southwestern United States and northwestern Mexico (Coleoptera). Proceedings, Entomological Society of Washington. 

83: 472–478.

White, R.E. 1982. A catalog of the Coleoptera of America 

north of Mexico. Family: Anobiidae. Agric. Handb. 529–70. 

Washington, DC: U.S. Department of Agriculture, Agricultural Research Service. xi–58.

White, R.E. 1983a. A new species of Ernobius (Coleoptera: 

Anobiidae) injurious to spruce. Proceedings, Entomological 

Society of Washington. 85: 557–559.

White, R.E. 1983b. Keys to neotropical species of Calymmaderus Solier and species of Calytheca White, with taxonomic notes (Coleoptera: Anobiidae). Proceedings of the 

Entomological Society of Washington. 85: 229–250.

White, R.E. 1984. A revision of the American genus 

Cryptorama (Coleoptera: Anobiidae). Transactions, 

American Entomological Society. 110: 77–127.

White, R.E. 1985. North American Euvrilletta (Coleoptera: 

Anobiidae)—transferal of taxa from Xyletinus, two new species, and a key. Coleopterists Bulletin. 39: 185–193.

White, R.E. 1990. Lasioderma haemorrhoidale (Ill.) now 

established in California, with biological data on Lasioderma species (Coleoptera: Anobiidae). The Coleopterists 

Bulletin. 44: 344–348.

Williams, L.H. 1973. Anobiid beetles should be controlled. 

Pest Control. 41: 18–22, 38–44.

Williams, L.H.; Mauldin, J.K. 1974. Anobiid beetle, Xyletinus peltatus (Coleoptera: Anobiidae), oviposition on various 

woods. The Canadian Entomologist. 106: 949–955.

Williams, L.H.; Mauldin, J.K. 1981. Survival and growth 

of the Anobiid beetle Xyletinus peltatus (Coleoptera: 

Anobiidae) in various woods. Canadian Entomologist. 

113: 651–657.

Williams, L.H.; Smythe, R.V. 1978. Wood-destroying beetle 

treatment incidence in Arkansas and Georgia during 1962 

and 1967 with estimated losses caused by beetles for 11 

southern states during 1970. Res. Pap. SO-143. New Orleans, LA: U.S. Department of Agriculture, Forest Service, 

Southern Forest Experiment Station. 12 p.

Woodroffe, G.E. 1953. An ecological study of the insects 

and mites in the nests of certain birds in Britain. Bulletin of 

Entomological Research. 44: 739–772.

Zayas, F. De. 1988. Entomofauna Cubana. Orden Coleoptera. Separata. Descripción de nuevas espécies. Editorial 

Científico-Técnica. 212 p.
Death-Watch and Spider Beetles of Wisconsin

91

Appendix A—Checklist of 

Wisconsin Ptinidae

[Species in bold are new state records]

PTININAE

Gibbium

 aequinoctiale Boieldieu

Mezium

 affine Boieldieu

Pseudeurostus

 hilleri (Reitter)

Ptinus

 bimaculatus Melsheimer

 clavipes Panzer

 concurrens Fall

 fur (Linnaeus)

 villiger (Reitter)

EUCRADINAE

Eucrada

 humeralis (Melsheimer)

ERNOBIINAE

Ernobius

 filicornis LeConte

 granulatus LeConte

 youngi Arango

ANOBIINAE

Hemicoelus

 carinatus (Say)

 defectus (Fall)

 pusillus (Fall)

 umbrosus (Fall)

Microbregma

 emarginatum (Duftschmid)

Hadrobregmus

 notatus (Say)

Priobium

 sericeum (Say)

Trichodesma

 gibbosa (Say)

Oligomerus

 alternans LeConte 

 brevipilis (Fall)

 obtusus LeConte

 sericans (Melsheimer)

Stegobium

 paniceum (Linnaeus)

PTILININAE

Ptilinus

 lobatus Casey

ruficornis Say

XYLETININAE

Euvrilletta

 brevis White

 harrisii (Fall)

 peltata (Harris)

Vrilletta

 laurentina Fall

Xyletinus

 confusus White

 fucatus LeConte

Lasioderma 

 serricorne (Fabricius)

DORCATOMINAE

Calymmaderus Solier

 nitidus (LeConte)

 obsoletus (Fall)

Byrrhodes

 incomptus (LeConte)

 intermedius (LeConte)

 tristriatus (LeConte)

Caenocara

 bicolor (Germar)

 blanchardi Fall

 inepta LeConte

 oculata (Say)

 tenuipalpa Fall

Dorcatoma

 falli White

 pallicornis LeConte

 setulosa LeConte

Petalium

 alternatum Ford

 bistriatum (Say)

 debile Fall

 incisum Ford

 seriatum Fall 

 whitei Ford

Protheca

 hispida LeConte

Sculptotheca

 puberula (LeConte)

Stagetus

 profundus (LeConte)

Striatheca

 lineata White

MESOCOELOPODINAE

Tricorynus

 borealis (LeConte)

 castaneus (Hamilton)

 confusus (Fall)

 dichrous (Fall)

 nigritulus (LeConte)

 punctatus (LeConte)

 similis (LeConte)

 
General Technical Report FPL–GTR–209

92

Appendix B—Wisconsin Distribution Maps

Map 1. Gibbium aequinoctiale Boieldieu

Map 2. Mezium affine Boieldieu

Map 3. Pseudeurostus hilleri (Reitter)

Map 4. Ptinus bimaculatus Melsheimer
Death-Watch and Spider Beetles of Wisconsin

93

Map 5. Ptinus clavipes Panzer

Map 6. Ptinus concurrens Fall

Map 7. Ptinus fur (Linnaeus)

Map 8. Ptinus villiger (Reitter)
General Technical Report FPL–GTR–209

94

Map 9. Eurada humeralis (Melsheimer)

Map 10. Ernobius filicornis LeConte

Map 11. Ernobius granulatus LeConte

Map 12. Ernobius youngi Arango
Death-Watch and Spider Beetles of Wisconsin

95

Map 13. Hemicoelus carinatus (Say)

Map 14. Hemicoelus defectus (Fall)

Map 15. Hemicoelus pusillus (Fall)

Map 16. Hemicoelus umbrosus (Fall)
General Technical Report FPL–GTR–209

96

Map 17. Microbregma emarginatum (Duftschmid)

Map 18. Hadrobregmus notatus (Say)

Map 19. Priobium sericeum (Say)

Map 20. Trichodesma gibbosa (Say)
Death-Watch and Spider Beetles of Wisconsin

97

Map 21. Oligomerus alternans LeConte

Map 22. Oligomerus brevipilis (Fall)

Map 23. Oligomerus obtusus LeConte

Map 24. Oligomerus sericans (Melsheimer)
General Technical Report FPL–GTR–209

98

Map 25. Stegobium paniceum (Linnaeus)

Map 26. Ptilinus lobatus Casey

Map 27. Ptilinus ruficornis Say

Map 28. Euvrilletta brevis White
Death-Watch and Spider Beetles of Wisconsin

99

Map 29. Euvrilletta harrisii (Fall)

Map 30. Euvrilletta peltata (Harris)

Map 31. Vrilletta laurentina Fall

Map 32. Xyletinus confusus White
General Technical Report FPL–GTR–209

100

Map 33. Xyletinus fucatus LeConte

Map 34. Lasioderma serricorne (Fabricius)

Map 35. Calymmaderus nitidus (LeConte)

Map 36. Calymmaderus obsoletus (Fall)
Death-Watch and Spider Beetles of Wisconsin

101

Map 37. Byrrhodes incomptus (LeConte)

Map 38. Byrrhodes intermedius (LeConte)

Map 39. Byrrhodes tristriatus (LeConte)

Map 40. Caenocara bicolor (Germar)
General Technical Report FPL–GTR–209

102

Map 41. Caenocara blanchardi Fall

Map 42. Caenocara inepta LeConte

Map 43. Caenocara oculata (Say)

Map 44. Caenocara tenuipalpa Fall
Death-Watch and Spider Beetles of Wisconsin

103

Map 45. Dorcatoma falli White

Map 46. Dorcatoma pallicornis LeConte

Map 47. Dorcatoma setulosa LeConte

Map 48. Petalium alternatum Ford
General Technical Report FPL–GTR–209

104

Map 49. Petalium bistriatum (Say)

Map 50. Petalium debile Fall

Map 51. Petalium incisum Ford

Map 52. Petalium seriatum Fall
Death-Watch and Spider Beetles of Wisconsin

105

Map 53. Petalium whitei Ford

Map 54. Protheca hispida LeConte

Map 55. Sculptotheca puberula (LeConte)

Map 56. Stagetus profundus (LeConte)
General Technical Report FPL–GTR–209

106

Map 57. Striatheca lineata White

Map 58. Tricorynus borealis (LeConte)

Map 59. Tricorynus castaneus (Hamilton)

Map 60. Tricorynus confusus (Fall)
Death-Watch and Spider Beetles of Wisconsin

107

Map 61. Tricorynus dichrous (Fall)

Map 62. Tricorynus nigritulus (LeConte)

Map 63. Tricorunus punctatus (LeConte)

Map 64. Tricorynus similis (LeConte)
General Technical Report FPL–GTR–209

108

Figure 1: Crex Meadows Wildlife Area

Figure 2: Schmidt Maple Woods

Figure 3: Augusta State Wildlife Area

Figure 4: Black River State Forest

Figure 5: Jung Hemlock–Beech Forest

Figure 6: Kettle Moraine Red Oaks
Death-Watch and Spider Beetles of Wisconsin

109

Figure 9: Ptilinus ruficornis female boring into cut Acer

negundo; pre-oviposition

Figure 10: Hemicoelus carinatus on grass near cut Acer 

negundo

Figure 11: Rearing chamber

Figure 12: Wood structure

Figure 7: 115+-year-old one-room school house

Figure 8: Ptinid damage to school house flooring
General Technical Report FPL–GTR–209

110

Plastic funnels (8)

Collection cup

Figure 13: Lindgren funnel trap

Figure 14: Flight intercept trap

Hole for string

Transparent Plexiglas window

Wooden board

Metal stake

Plastic collection tray
Death-Watch and Spider Beetles of Wisconsin

111

Figure 15: Wisconsin vegetation map (scanned); from Robert W. Finley 1976, USDA Forest Service, North Central 

Forest Experiment Station.
General Technical Report FPL–GTR–209

112Figure 17: Generalized ptinid body form

Figure 18: Generalized ptinid body form Figure 16: Generalized ptinid body form
Death-Watch and Spider Beetles of Wisconsin

113

Figure 25: Eucrada humeralis (Melsheimer), antennae, 

female

Figure 26: Ernobius filicornis LeConte, antennae, male

Figure 27: Oligomerus sericans (Melsheimer), antennae, 

male

Figure 28: Priobium sericeum (Say), antennae

Figure 19: Pseudeurostus hilleri (Reitter), antennae

Figure 20: Ptinus bimaculatus Melsheimer, antennae

Figure 21: Ptinus fur (Linnaeus), antennae, male

Figure 22: Ptinus fur (Linnaeus), antennae, female

Figure 23: Gibbium aequinoctiale Boieldieu, antennae

Figure 24: Eucrada humeralis (Melsheimer), antennae, male
General Technical Report FPL–GTR–209

114

Figure 29: Stegobium paniceum (Linnaeus), antennae

Figure 30: Trichodesma gibbosa (Say), antennae

Figure 31: Hadrobregmus notatus (Say), antennae

Figure 32: Microbregma emarginata (Duftschmid), antennae

Figure 33: Hemicoelus carinatus (Say), antennae, male

Figure 34: Hemicoelus carinatus (Say), antennae, female

Figure 35: Hemicoelus pusillus (Fall), antennae, male

Figure 36: Ptilinus ruficornis Say, antennae, male

Figure 37: Ptilinus ruficornis Say, antennae, female

Figure 38: Lasioderma serricorne (Fabricius), antennae; 

adapted from Philips 2002
Death-Watch and Spider Beetles of Wisconsin

115

Figure 41: Euvrilletta brevis White, antennae, female; adapted from White 1985

Figure 42: Euvrilletta harrisii (Fall), antennae, male; adapted 

from White 1985

Figure 43: Euvrilletta harrisii (Fall), antennae, female; adapted from White 1985

Figure 44: Xyletinus confusus White, antennae, male

Figure 45: Petalium bistriatum (Say), antennae

Figure 46: Petalium seriatum Fall, antennae

Figure 47: Calymmaderus obsoletus (Fall), antennae

Figure 48: Caenocara bicolor (Germar), antennae, male; 

adapted from Fall 1905

Figure 39: Vrilletta laurentina Fall, antennae

Figure 40: Euvrilletta brevis White, antennae, male; adapted 

from White 1985
General Technical Report FPL–GTR–209

116

Figure 57: Byrrhodes tristriatus LeConte, antennae, female

Figure 58: Tricorynus confusus (Fall), antennae; adapted 

from White 1963

Figure 49: Caenocara blanchardi Fall, antennae, male; 

adapted from Fall 1905

Figure 50: Caenocara oculata (Say), antennae, male; adapted from Fall 1905

Figure 51: Caenocara oculata (Say), antennae, female; 

adapted from Fall 1905

Figure 52: Caenocara tenuipalpa Fall, antennae, male; 

adapted from Fall 1905

Figure 53: Protheca hispida LeConte, antennae

Figure 54: Sculptotheca puberula (LeConte), antennae

Figure 55: Dorcatoma falli White, antennae

Figure 56: Byrrhodes incomptus (LeConte), antennae, male
Death-Watch and Spider Beetles of Wisconsin

117

Figure 59: Euvrilletta peltata (Harris), 

terminal maxillary palpomere

Figure 60: Euvrilletta harrisii (Fall), 

terminal maxillary palpomere

Figure 61: Caenocara blanchardi

Fall, terminal maxillary palpomere; 

adapted from Fall 1905

Figure 62: Caenocara oculata

(Say), terminal maxillary palpomere; 

adapted from Fall 1905

Figure 63: Caenocara tenuipalpa

Fall, terminal maxillary palpomere; 

adapted from Fall 1905

Figure 64: Dorcatoma sp., 

prosternal process

Figure 65: Byrrhodes sp., 

prosternal process

Figure 66: Stegobium paniceum

(Linnaeus), tarsal claw, male; 

adapted from Halstead 1986

Figure 67: Stegobium paniceum

(Linnaeus), tarsal claw, female; 

adapted from Halstead1986

Figure 68: Trichodesma gibbosa (Say), 

tarsal claw Figure 69: Hemicoelus sp., tarsal claw
General Technical Report FPL–GTR–209

118

Figure 70: Pseudeurostus hilleri (Reitter), abdomen; adapted 

from Spilman 1991

Figure 74: Hemicoelus pusillus (Fall), 

abdomen

Figure 71: Ptinus fur (Linnaeus), abdomen

Figure 72: Gibbium sp., abdomen; adapted from Spilman 1991

Figure 73: Hemicoelus carinatus (Say), abdomen
Death-Watch and Spider Beetles of Wisconsin

119

Figure 75: Tricorynus punctatus (LeConte), pro- and mesothoracic 

legs

Figure 76: Hemicoelus sp., elytral punctures Figure 77: Oligomerus sp., elytral punctures

Figure 78: Ptilinus ruficornis Say, abdomen, 

female

Figure 79: Hadrobregmus notatus (Say), 

abdomen
General Technical Report FPL–GTR–209

120

Figure 80: Dorcatoma falli White, metathoracic ventrite

Figure 81: Dorcatoma pallicornis LeConte, metathoracic 

ventrite

Figure 82: Petalium incisum Ford, metathoracic 

ventrite

Figure 83: Tricorynus punctatus (LeConte), metathoracic 

ventrite
Death-Watch and Spider Beetles of Wisconsin

121

Figure 84: Ptinus villiger (Reitter), frons

Figure 85: Oligomerus sericans (Melsheimer), frons

Figure 86: Hemicoelus carinatus (Say), prothorax, ventral

Figure 87: Ernobius sp., prothorax, ventral
General Technical Report FPL–GTR–209

122

Figure 88: Euvrilletta harrisii (Fall), frons

Figure 89: Xyletinus fucatus LeConte, frons

Figure 90: Petalium incisum Ford, pronotal notch

Figure 91: Petalium whitei Ford, pronotum 

without notch
Death-Watch and Spider Beetles of Wisconsin

123

Figure 92: Ptilinus ruficornis Say, pronotal apex with asperities, female

Figure 93: Oligomerus sericans (Melsheimer), left antenna

Figure 94: Oligomerus sericans (Melsheimer), right antenna. (SEM images taken by Tom Kuster)
General Technical Report FPL–GTR–209

124

Figure 95: Oligomerus sericans (Melsheimer), genitalia, 

dorsal, male

Figure 96: Oligomerus brevipilis (Fall), genitalia 

dorsal, male

Figure 97: Oligomerus obtusus LeConte, genitalia dorsal, 

male

Figure 98: Oligomerus alternans LeConte, genitalia dorsal, 

male
Death-Watch and Spider Beetles of Wisconsin

125

Figure 99: Gibbium aequinoctiale Boieldieu, dorsal

Figure 100: Gibbium aequinoctiale Boieldieu, lateral

Figure 101: Mezium affine Boieldieu, dorsal

Figure 102: Mezium affine Boieldieu, lateral
General Technical Report FPL–GTR–209

126

Figure 103: Pseudeurostus hilleri (Reitter), 

dorsal

Figure 104: Pseudeurostus hilleri (Reitter), lateral

Figure 105: Ptinus bimaculatus

Melsheimer, dorsal

Figure 106: Ptinus bimaculatus Melsheimer, lateral
Death-Watch and Spider Beetles of Wisconsin

127

Figure 107: Ptinus clavipes Panzer, 

dorsal

Figure 108: Ptinus clavipes Panzer, lateral

Figure 109: Ptinus concurrens

Fall, dorsal

Figure 110: Ptinus concurrens Fall, lateral
General Technical Report FPL–GTR–209

128

Figure 111: Ptinus fur (Linnaeus), dorsal, male

Figure 112: Ptinus fur (Linnaeus), lateral, male

Figure 113: Ptinus fur (Linnaeus), dorsal, female

Figure 114: Ptinus fur (Linnaeus), lateral, female
Death-Watch and Spider Beetles of Wisconsin

129

Figure 115: Ptinus villiger (Reitter), 

dorsal, male

Figure 116: Ptinus villiger (Reitter), lateral, male

Figure 117: Ptinus villiger

(Reitter), dorsal, female

Figure 118: Ptinus villiger (Reitter), lateral, female
General Technical Report FPL–GTR–209

130

Figure 119: Eucrada humeralis (Melsheimer), 

dorsal, male

Figure 120: Eucrada humeralis (Melsheimer), lateral, male

Figure 121: Eucrada humeralis (Melsheimer), dorsal, 

female

Figure 122: Eucrada humeralis (Melsheimer), lateral, 

female
Death-Watch and Spider Beetles of Wisconsin

131

Figure 123: Ernobius filicornis LeConte, 

dorsal, male

Figure 124: Ernobius filicornis LeConte, lateral, male

Figure 125: Ernobius granulatus

LeConte, dorsal, male

Figure 126: Ernobius granulatus LeConte, lateral, male
General Technical Report FPL–GTR–209

132

Figure 127: Ernobius youngi

Arango, dorsal, female 

(Holotype)

Figure 128: Ernobius youngi Arango, lateral, female 

(Holotype)

Figure 129: Hemicoelus 

carinatus (Say), dorsal, 

female

Figure 130: Hemicoelus carinatus (Say), lateral, female
Death-Watch and Spider Beetles of Wisconsin

133

Figure 131: Hemicoelus defectus

(Fall), dorsal

Figure 132: Hemicoelus defectus (Fall), lateral

Figure 133: Hemicoelus pusillus

(Fall), dorsal

Figure 134: Hemicoelus pusillus (Fall), lateral
General Technical Report FPL–GTR–209

134

Figure 135: Hemicoelus umbrosus

(Fall), dorsal

Figure 136: Hemicoelus umbrosus (Fall), lateral

Figure 137: Microbregma emarginatum 

emarginatum (Duftschmid), dorsal

Figure 138: Microbregma emarginatum emarginatum

(Duftschmid), lateral
Death-Watch and Spider Beetles of Wisconsin

135

Figure 139: Hadrobregmus notatus

(Say), dorsal

Figure 140: Hadrobregmus notatus (Say), lateral

Figure 141: Priobium sericeum (Say), 

dorsal

Figure 142: Priobium sericeum (Say), lateral
General Technical Report FPL–GTR–209

136

Figure 143: Trichodesma gibbosa

(Say), dorsal

Figure 144: Trichodesma gibbosa (Say), lateral

Figure 145: Oligomerus 

alternans LeConte, dorsal

Figure 146: Oligomerus alternans LeConte, lateral
Death-Watch and Spider Beetles of Wisconsin

137

Figure 147: Oligomerus brevipilis

Fall, dorsal

Figure 148: Oligomerus brevipilis Fall, lateral

Figure 149: Oligomerus obtusus LeConte, dorsal, male

Figure 150: Oligomerus obtusus LeConte, lateral, male
General Technical Report FPL–GTR–209

138

Figure 151: Oligomerus 

sericans (Melsheimer), 

dorsal, male

Figure 152: Oligomerus sericans (Melsheimer), lateral, male

Figure 153: Stegobium paniceum

(Linnaeus), dorsal

Figure 154: Stegobium paniceum (Linnaeus), lateral
Death-Watch and Spider Beetles of Wisconsin

139

Figure 155: Ptilinus lobatus Casey, 

dorsal, male

Figure 156: Ptilinus lobatus Casey, lateral, male

Figure 157: Ptilinus ruficornis Say, dorsal, male

Figure 158: Ptilinus ruficornis Say, lateral, male
General Technical Report FPL–GTR–209

140

Figure 159: Ptilinus ruficornis

Say, dorsal, female

Figure 160: Ptilinus ruficornis Say, lateral, female

Figure 161: Euvrilletta brevis White, dorsal

Figure 162: Euvrilletta brevis White, lateral
Death-Watch and Spider Beetles of Wisconsin

141

Figure 163: Euvrilletta 

harrisii (Fall), dorsal

Figure 164: Euvrilletta harrisii (Fall), lateral

Figure 165: Euvrilletta 

peltata (Harris), dorsal

Figure 166: Euvrilletta peltata (Harris), lateral
General Technical Report FPL–GTR–209

142

Figure 167: Vrilletta laurentina

Fall, dorsal

Figure 168: Vrilletta laurentina Fall, lateral

Figure 169: Xyletinus confusus

White, dorsal, male

Figure 170: Xyletinus confusus White, lateral, male
Death-Watch and Spider Beetles of Wisconsin

143

Figure 171: Xyletinus 

fucatus LeConte, dorsal

Figure 172: Xyletinus fucatus LeConte, lateral

Figure 173: Lasioderma serricorne (Fabricius), dorsal

Figure 174: Lasioderma serricorne (Fabricius), lateral
General Technical Report FPL–GTR–209

144

Figure 175: Calymmaderus nitidus

(LeConte), dorsal

Figure 176: Calymmaderus nitidus (LeConte), lateral

Figure 177: Calymmaderus obsoletus

(Fall), dorsal

Figure 178: Calymmaderus obsoletus (Fall), lateral
Death-Watch and Spider Beetles of Wisconsin

145

Figure 179: Byrrhodes incomptus

(LeConte), dorsal

Figure 180: Byrrhodes incomptus (LeConte), lateral

Figure 181: Byrrhodes intermedius

(LeConte), dorsal

Figure 182: Byrrhodes intermedius (LeConte), lateral
General Technical Report FPL–GTR–209

146

Figure 183: Byrrhodes tristriatus

(LeConte), dorsal

Figure 184: Byrrhodes tristriatus (LeConte), lateral

Figure 185: Caenocara bicolor (Germar), dorsal

Figure 186: Caenocara bicolor (Germar), lateral
Death-Watch and Spider Beetles of Wisconsin

147

Figure 187: Caenocara blanchardi Fall, 

dorsal, female

Figure 188: Caenocara blanchardi Fall, lateral, female

Figure 189: Caenocara inepta

LeConte, dorsal

Figure 190: Caenocara inepta LeConte, lateral
General Technical Report FPL–GTR–209

148

Figure 191: Caenocara oculata (Say), 

dorsal, male

Figure 192: Caenocara oculata (Say), lateral, male

Figure 193: Caenocara tenuipalpa

Fall, dorsal

Figure 194: Caenocara tenuipalpa Fall, lateral
Death-Watch and Spider Beetles of Wisconsin

149

Figure 195: Dorcatoma falli White, 

dorsal

Figure 196: Dorcatoma falli White, lateral

Figure 197: Dorcatoma pallicornis

LeConte, dorsal

Figure 198: Dorcatoma pallicornis LeConte, lateral
General Technical Report FPL–GTR–209

150

Figure 199: Dorcatoma setulosa

LeConte, dorsal

Figure 200: Dorcatoma setulosa LeConte, lateral

Figure 201: Petalium 

alternatum Ford, dorsal

Figure 202: Petalium alternatum Ford, lateral
Death-Watch and Spider Beetles of Wisconsin

151

Figure 203: Petalium bistriatum

(Say), dorsal

Figure 204: Petalium bistriatum (Say), lateral

Figure 205: Petalium debile Fall, 

dorsal

Figure 206: Petalium debile Fall, lateral
General Technical Report FPL–GTR–209

152

Figure 207: Petalium incisum

Ford, dorsal

Figure 208: Petalium incisum Ford, lateral

Figure 209: Petalium 

seriatum Fall, dorsal

Figure 210: Petalium seriatum Fall, lateral
Death-Watch and Spider Beetles of Wisconsin

153

Figure 211: Petalium whitei

Ford, dorsal

Figure 212: Petalium whitei Ford, lateral

Figure 213: Protheca hispida

LeConte, dorsal

Figure 214: Protheca hispida LeConte, lateral
General Technical Report FPL–GTR–209

154

Figure 215: Sculptotheca puberula

(LeConte), dorsal

Figure 216: Sculptotheca puberula (LeConte), lateral

Figure 217: Stagetus profundus

(LeConte), dorsal

Figure 218: Stagetus profundus (LeConte), lateral
Death-Watch and Spider Beetles of Wisconsin

155

Figure 219: Striatheca lineata White, 

dorsal

Figure 220: Striatheca lineata White, lateral

Figure 221: Tricorynus borealis

(LeConte), dorsal

Figure 222: Tricorynus borealis (LeConte), lateral
General Technical Report FPL–GTR–209

156

Figure 223: Tricorynus castaneus

(Hamilton), dorsal

Figure 224: Tricorynus castaneus (Hamilton), lateral

Figure 225: Tricorynus confusus

(Fall), dorsal

Figure 226: Tricorynus confusus (Fall), lateral
Death-Watch and Spider Beetles of Wisconsin

157

Figure 227: Tricorynus dichrous

(Fall), dorsal

Figure 228: Tricorynus dichrous (Fall), lateral

Figure 229: Tricorynus nigritulus

(LeConte), dorsal

Figure 230: Tricorynus nigritulus (LeConte), lateral
General Technical Report FPL–GTR–209

158

Figure 231: Tricorynus punctatus

(LeConte), dorsal

Figure 232: Tricorynus punctatus (LeConte), lateral

Figure 233: Tricorynus similis

(LeConte), dorsal

Figure 234: Tricorynus similis (LeConte), lateral