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smithsonian contributions to zoology • number 637

A Revision of the Nearctic

Species of the Genus 

Trixoscelis Rondani 

(Diptera: Heleomyzidae: 

Trixoscelidinae) 

George A. Foster and Wayne N. Mathis
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smithsonian contributions to zoology • number 637

A Revision of the Nearctic 

Species of the Genus 

Trixoscelis Rondani 

(Diptera: Heleomyzidae: 

Trixoscelidinae)

George A. Foster and Wayne N. Mathis

washington d.c.

2011
ABSTRACT

Foster, George A., and Wayne N. Mathis. A Revision of the Nearctic Species of the Genus 

Trixoscelis Rondani (Diptera: Heleomyzidae: Trixoscelidinae). Smithsonian Contributions 

to Zoology, number 637, viii + 128 pages, 187 figures, 1 table, 2011.—The Nearctic species 

of the genus Trixoscelis Rondani are revised. Thirteen new species are described, seven new 

combinations and three new synonyms are proposed, and three species groups are characterized. Keys to the 38 known species are provided. Diagnoses, detailed distributional data for 

the species of the genus, notes on the biology, and illustrations (photographs and drawings) 

are included to assist species identification. A phylogenetic analysis was performed to test the 

monophyly of the genus Trixoscelis and the included species groups. The ingroup includes 

a total of 38 exemplar species. Outgroup sampling includes the following exemplar genera: Neossos, Waterhousea, Fenwickia, Aneuria, and Xenura. Analyses, including implied 

weighting, recovered a monophyletic Trixoscelis and species groups if the Mongolian genus 

Paratrixoscelis is included within Trixoscelis.

Cover image: Trixoscelis fumipennis Melander, Figure 1.

Published by Smithsonian Institution Scholarly Press

P.O. Box 37012, MRC 957

Washington, D.C. 20013-7012

www.scholarlypress.si.edu

Text and images in this publication may be protected by copyright and other restrictions or owned by 

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Library of Congress Cataloging-in-Publication Data

Foster, George A. (George Arnold), 1954–

A revision of the Nearctic species of the genus Trixoscelis Rondani (Diptera: Heleomyzidae: 

Trixoscelidinae) / George A. Foster and Wayne N. Mathis.

 p. cm. — (Smithsonian contributions to zoology ; no. 637)

Includes bibliographical references.

1. Heleomyzidae—Classification. 2. Diptera—Classification. 3. Flies. I. Mathis, Wayne N. 

II. Title. III. Series: Smithsonian contributions to zoology ; no. 637.

QL537.H44F67 2011

595.77'3—dc23

2011027004

ISSN: 0081-0282 (print); 1943-6696 (online)

The paper used in this publication meets the minimum requirements of the American National Standard 

for Permanence of Paper for Printed Library Materials Z39.48–1992.
Contents

LIST OF FIGURES v

INTRODUCTION 1

Taxonomic History of the Nearctic Fauna 1

Methods and Materials 2

Acknowledgments 3

SYSTEMATICS 4

Genus Trixoscelis Rondani 4

 Characters Used in the Analysis 6

 Key to Nearctic Species of the T. fumipennis and T. claripennis 

Species Groups 9

 The T. fumipennis Species Group 10

 Trixoscelis albibasis (Malloch), new combination 10

 Trixoscelis bajaensis Foster and Mathis, new species 11

 Trixoscelis bifurcata Foster and Mathis, new species 14

 Trixoscelis buccata Melander 17

 Trixoscelis costalis (Coquillett) 21

 Trixoscelis deserta Melander 23

 Trixoscelis desertensis Foster and Mathis, new species 26

 Trixoscelis fumipennis Melander 30

 Trixoscelis gigapeza Foster and Mathis, new species 35

 Trixoscelis granditarsa (Foster and Mathis), 

new combination 36

 Trixoscelis nevadensis Foster and Mathis, new species 39

 Trixoscelis nigripeza Foster and Mathis, new species 41

 Trixoscelis ornata (Johnson), new combination 43

 Trixoscelis polita (Malloch), new combination 46

 Trixoscelis punctipennis (Melander), new combination 49

 Trixoscelis pygochroa Melander 51

 Trixoscelis suffusa Melander 54

 Trixoscelis triplex Melander 59

 Trixoscelis tumida Melander 61
i v • smithsonian contributions to zoology

 The T. claripennis Species Group 64

 Trixoscelis barberi Foster and Mathis, new species 64

 Trixoscelis claripennis (Malloch) 66

 Trixoscelis flavens Melander 69

 Trixoscelis flavida Melander 74

 Trixoscelis lagunaensis Foster and Mathis, new species 85

 Trixoscelis nitidiventris Melander 86

 Trixoscelis plebs Melander 89

 Trixoscelis signifera Melander 91

Key to Nearctic Species of the T. nuda Species Group 94

 The nuda Species Group 94

 Trixoscelis annetteae Foster and Mathis, new species 95

 Trixoscelis arnaudi Foster and Mathis, new species 97

 Trixoscelis cinerea (Coquillett) 100

 Trixoscelis coloradensis Foster and Mathis, new species 104

 Trixoscelis crepida Foster and Mathis, new species 105

 Trixoscelis flava (Coquillett), new combination 106

 Trixoscelis flavicornis (Melander), new combination 109

 Trixoscelis kernensis Foster and Mathis, new species 111

 Trixoscelis litorea (Aldrich) 115

 Trixoscelis melanderi Vockeroth 117

 Trixoscelis nuda Coquillett 119

REFERENCES 125

index to the species of trixoscelis 127
Figures

1. Frontispiece. Trixoscelis fumipennis Melander 3

2. Consensus cladogram depicting hypothetical cladistic 

relationships among species groups of Trixoscelis 7

3–4. Structures of male terminalia of Trixoscelis albibasis 

(Malloch) 11

5. Distribution map for Trixoscelis albibasis (Malloch) 12

6–8. Structures of male terminalia of Trixoscelis bajaensis 

Foster and Mathis 13

9. Distribution map for Trixoscelis bajaensis Foster and 

Mathis 14

10–12. Structures of male terminalia of Trixoscelis bifurcata 

Foster and Mathis 15

13. Distribution map for Trixoscelis barberi Foster and 

Mathis, T. bifurcata Foster and Mathis, T. coloradensis 

Foster and Mathis, and T. desertensis Foster and Mathis 16

14–17. Structures of male terminalia of Trixoscelis buccata 

Melander 18

18. Distribution map for Trixoscelis buccata Melander 19

19–24. Photographs of Trixoscelis heads 20

25–27. Structures of male terminalia of Trixoscelis costalis 

(Coquillett) 22

28. Distribution map for Trixoscelis costalis (Coquillett) 23

29–32. Structures of male terminalia of Trixoscelis deserta 

Foster and Mathis 25

33. Distribution map for Trixoscelis deserta Melander 27

34–41. Photographs of right wings, dorsal aspects 28

42–45. Structures of male terminalia of Trixoscelis desertensis 

Foster and Mathis (California. Riverside: Palm Springs) 29

46–49. Structures of male terminalia of Trixoscelis fumipennis 

Melander (Canada. Manitoba: Treesbank) 31

50. Distribution map for Trixoscelis fumipennis Melander 35
v i • smithsonian contributions to zoology

51. Structures of male terminalia of Trixoscelis gigapeza 

Foster and Mathis 36

52. Distribution map for Trixoscelis gigapeza Foster and 

Mathis 37

53–55. Structures of male terminalia of Trixoscelis granditarsa 

(Foster and Mathis) (California. San Bernardino: 

Poison Canyon) 38

56. Distribution map for Trixoscelis granditarsa (Foster 

and Mathis) 39

57–62. Photographs of Trixoscelis heads 40

63. Distribution map for Trixoscelis lagunaensis Foster 

and Mathis, T. nigripeza Foster and Mathis, and 

T. nevadensis Foster and Mathis 42

64–65. Structures of male terminalia of Trixoscelis nevadensis 

Foster and Mathis (Nevada. Clark: Red Rock Canyon) 43

66–68. Structures of male terminalia of Trixoscelis nigripeza 

Foster and Mathis (Mexico. Baja California Sur. 

Rancho Tablon) 44

69. Structures of male terminalia of Trixoscelis ornata 

(Johnson) (Dominican Republic. LaVega: near Jarabacoa, 

Salto Baiguate) 45

70. Distribution map for Trixoscelis ornata (Johnson) 47

71–73. Structures of male terminalia of Trixoscelis polita 

(Malloch) (Mexico. Baja California: Los Barriles) 48

74. Distribution map for Trixoscelis polita (Malloch) 50

75. Structures of male terminalia of Trixoscelis punctipennis

(Melander) 51

76. Distribution map for Trixoscelis punctipennis 

(Melander) 52

77–81. Structures of male terminalia of Trixoscelis pygochroa 

Melander 53

82. Distribution map for Trixoscelis pygochroa Melander 55

83–86. Structures of male terminalia of Trixoscelis suffusa 

Melander 56

87. Distribution map for Trixoscelis suffusa Melander 57

88–95. Photographs of right wings, dorsal aspects 58

96–98. Structures of male terminalia of Trixoscelis triplex 

Melander (locality unknown) 60

99. Distribution map for Trixoscelis triplex Melander 61

100–103. Structures of male terminalia of Trixoscelis tumida 

Melander (locality unknown) 63

104. Distribution map for Trixoscelis tumida Melander 65

105. Structures of male terminalia of Trixoscelis barberi 

Foster and Mathis (California. Orange: Corona del Mar) 66

106–109. Structures of male terminalia of Trixoscelis claripennis

(Malloch) (California. Los Angeles: Whitewater Canyon) 68

110. Distribution map for Trixoscelis claripennis (Malloch) 70

111–114. Structures of male terminalia of Trixoscelis flavens 

Melander (Utah. Emery: Wild Horse Creek) 71
number 637 • vii

115. Distribution map for Trixoscelis flavens Melander 72

116–121. Photographs of Trixoscelis heads 73

122–125. Structures of male terminalia of Trixoscelis flavida 

Melander (labeled as T. frontalis) (Washington. Walla 

Walla: Mill Creek) 75

126. Distribution map for Trixoscelis flavida Melander 84

127–128. Structures of male terminalia of Trixoscelis lagunaensis 

Foster and Mathis 86

129–131. Structures of male terminalia of Trixoscelis nitidiventris

Melander (Oregon. Lake: 16 km NE Christmas Valley) 87

132. Distribution map for Trixoscelis nitidiventris Melander 88

133–135. Structures of male terminalia of Trixoscelis plebs 

Melander (Nevada. Clark: Las Vegas Wash) 90

136. Distribution map for Trixoscelis plebs Foster and 

Mathis 91

137. Distribution map for Trixoscelis signifera Melander 93

138–140. Structures of male terminalia of Trixoscelis annettae 

Foster and Mathis (California. San Diego: Palm Canyon) 95

141. Distribution map for Trixoscelis annettae Foster and 

Mathis 97

142–147. Photographs of Trixoscelis heads 98

148–151. Structures of male terminalia of Trixoscelis arnaudi 

Foster and Mathis 99

152. Distribution map for Trixoscelis arnaudi Foster and 

Mathis 101

153–154. Structures of male terminalia of Trixoscelis cinerea 

(Coquillett) (California. Dan Diego: Cardiff-by-Sea) 102

155. Distribution map for Trixoscelis cinerea (Coquillett) 103

156–157. Structures of male terminalia of Trixoscelis coloradensis 

Foster and Mathis (Colorado. Gunnison: Almont) 104

158–160. Structures of male terminalia of Trixoscelis crepida Foster 

and Mathis (California. San Diego: Palomar Mountain) 106

161. Distribution map for Trixoscelis crepida Foster and 

Mathis 107

162. Structures of male terminalia of Trixoscelis flava 

(Coquillett) 108

163. Distribution map for Trixoscelis flava (Coquillett) 109

164. Structures of male terminalia of Trixoscelis flavicornis

(Melander) 110

165. Distribution map for Trixoscelis flavicornis (Melander) 111

166–171. Photographs of Trixoscelis heads 112

172–173. Structures of male terminalia of Trixoscelis kernensis 

Foster and Mathis (California. Kern: Kelso Valley, 

Weldon) 113

174. Distribution map for Trixoscelis kernensis Foster and 

Mathis 114

175–177. Structures of male terminalia of Trixoscelis litorea 

(Aldrich) (California. Merced: Hilmar) 116

178. Distribution map for Trixoscelis litorea (Aldrich) 117
viii • smithsonian contributions to zoology

179–181. Structures of male terminalia of Trixoscelis melanderi

Vockeroth 118

182. Distribution map for Trixoscelis melanderi Vockeroth 120

183–186. Structures of male terminalia of Trixoscelis nuda 

(Coquillett) (California. Los Angeles: Claremont) 121

187. Distribution map for Trixoscelis nuda (Coquillett) 123
A Revision of the Nearctic Species 

of the Genus Trixoscelis Rondani 

(Diptera: Heleomyzidae: Trixoscelidinae)

INTRODUCTION

Recent collecting in western North America has resulted in the discovery 

of many undescribed species of the genus Trixoscelis Rondani. These discoveries prompted this revision of all Nearctic species of the genus, especially 

since the last study of this fauna was published over 50 years ago (Melander, 

1952) and is now woefully out of date and inadequate. For example, some of 

Melander’s species are difficult to identify because many of the diagnostic characters have been found to be highly variable. Additionally, Melander focused 

very little on structures of the male terminalia, which we have found to be 

quite reliable for distinguishing species. In addition to describing the recently 

discovered Nearctic species, we are providing new data, synonymies, revised 

descriptions, comments, distributional data, and illustrations for all included 

species. A revised key to species is also provided. We have included a detailed 

treatment of T. costalis (Coquillett) from the Galápagos Islands in this study 

because this species had erroneously been reported from Arizona (Coquillett, 

1902) and because we have had access to a series of 93 specimens from various 

Galápagos Islands.

Taxonomic History of the Nearctic Fauna

Hendel (1911) was the first to recognize the genus Trixoscelis in North 

America when he described T. prima from specimens collected in Claremont, 

California [cited incorrectly as Claremont, New Hampshire]. Two years later, 

Melander published two papers that treated Trixoscelis. In his first paper (Melander, 1913a), Melander described the second Nearctic species, T. fumipennis,

and noted that (p. 169) “Hendel’s Trixoscelis prima is the same as Parodinia 

cinerea Coquillett” and reported that Malloch had described specimens of 

George A. Foster and Wayne N. Mathis, Department of Entomology, P.O. Box 37012, MRC

169, Smithsonian Institution, Washington, D.C. 

20013-7012, USA; Correspondence: george

foster_64@hotmail.com; mathisw@si.edu. Manuscript received 20 August 2010; accepted 26 May 

2011.
2 • smithsonian contributions to zoology

P. costalis Coquillett as P. claripennis (Malloch). Although 

Melander did not formally place these species in Trixoscelis, he clearly suggested such in his remarks about 

T. fumipennis. Significantly, Melander also misidentified 

Malloch’s species as the European T. frontalis (Fallén), a 

precedent that was perpetuated by various authors until 

this study. In a later treatment of T. frontalis, Melander 

(1952:46) acknowledged that he “[did] not have European specimens for verification” but that it “seems to be 

identical with T. frontalis.” In this study, we document 

that T. frontalis is not known from North America.

In December of 1913, Melander (1913b) published his 

second paper, which included a key to the known Nearctic species of Trixoscelis (in the subfamily Geomyzinae). 

The following species were treated in his key: T. costalis

Coquillett (Parodinia: Rhicnoessa), T. cinerea Coquillett 

(formerly in Parodinia), T. frontalis Fallén (misidentification), T. prima Hendel, and Siligo litorea Aldrich. Curiously, Melander either ignored or overlooked his previous 

synonymy of T. prima Hendel with T. cinerea (Coquillett) 

from his first paper of that year.

Aldrich (1929) formally placed both T. cinerea (Coquillett) and T. nuda (Coquillett) in Trixoscelis and also 

placed T. prima Hendel in synonymy with T. nuda. Malloch (1931) noted that Diastata Meigen and Trixoscelis

are synonyms because both have the same type species, 

Geomyza obscurella Fallén (1823). Malloch treated Spilochroa Williston as a subgenus of Diastata in this study and 

in a second paper (Malloch, 1933).

Melander (1952) published the only major revision 

of the family for the North American fauna and included 

four genera: Neossos Malloch, Zagonia Coquillett, Spilochroa Williston, and Trixoscelis. He described 14 new species of Trixoscelis, and in the present study, we have found 

that all but two, T. mohavea and T. sagulata, are valid. 

Melander’s new species are only known to occur in western North America, which we further document in this 

paper, to be the current center of species diversity in the 

New World.

Cogan (1977), in a review of the Afrotropical fauna 

of Trixoscelis, combined the genus Spilochroa with Trixoscelis because the characters used to differentiate these 

two genera, namely, the strongly patterned wing and weak 

oral vibrissae of Spilochroa, are quite variable. McAlpine 

(1985) accepted this synonymy and added Zagonia as another junior, generic synonym. We concur with McAlpine and herein combine both Spilochroa and Zagonia in 

Trixoscelis. McAlpine (1985) also provided evidence for 

recognizing the former family Trixoscelididae as the tribe 

Trixoscelidini in the family Heleomyzidae. Teskey (1987) 

conditionally maintained the generic status of Spilochroa

and Zagonia in the Manual of Nearctic Diptera.

Methods and Materials

The descriptive terminology for external structures 

and many internal structures follows that published in 

the Manual of Nearctic Diptera (McAlpine, 1981). For 

structures of the male terminalia, however, we have adopted the terminology that Cumming et al. (1995) have 

suggested. Because specimens are small, usually less than 

4 mm in length, study and illustration required use of dissecting and compound microscopes. The descriptions of 

new species are based primarily on their holotypes with 

variation being accounted for in the Remarks section. One 

head ratio, used in the descriptions, is defined below. 

Ratios are averages of three specimens the largest, 

smallest, and one other. The gena-to-eye ratio is the genal 

height measured at the maximum eye height, viewed in 

direct profile, divided by the eye height.

Label data from each specimen were recorded and 

listed alphabetically according to country, state or province, county, and specific locality, such as city. As available, 

date of collection, collector, sex, and specimen depository 

were listed. If a field of data is not on the label, such as 

the date when the specimen was collected or the collector’s 

name, these data are not provided in the Specimens Examined section. Label data from holotype specimens were recorded exactly, and clarifying information, such as script 

style and label color, is enclosed within brackets.

Distribution maps were made using ESRI ArcView 

GIS 3.2. Longitude and latitude coordinates were obtained for the locality where each specimen was collected 

and entered into a Microsoft Excel spreadsheet. If unavailable directly from specimen labels, longitude and latitude 

were estimated using gazetteers and maps to determine the 

geographical coordinates. Our use of “Nearctic Region” 

and “Neotropical Region” in distribution sections under 

each species follows the delimitations used in the most 

recent catalogs of Diptera for those regions (Vockeroth, 

1965; Gill, 1968); that is, the border between Mexico and 

United States is the boundary between these regions.

The phylogenetic analysis was performed with the assistance of TNT, a computerized algorithm that produces 

cladograms by parsimony. Character data were polarized 

primarily using outgroup procedures.

Dissections of male and female terminalia and descriptions were performed using the method of Clausen 

and Cook (1971) and Grimaldi (1987). Microforceps 

were used to remove abdomens, which were macerated 
number 637 • 3

in a potassium or sodium hydroxide solution. Cleared 

structures were rinsed in distilled water and then transferred to glycerin for observation. If necessary for proper 

orientation, the specimen was transferred from glycerin to 

glycerin jelly. The glycerin jelly was heated, and the specimen appropriately oriented. After cooling, the embedded 

specimen in glycerin jelly became immobilized. Abdomens 

were placed in a plastic microvial filled with glycerin and 

attached to the pin supporting the remainder of the insect 

from which it was removed. For freshly caught specimens, 

we recommend that the epandrium and associated structures of the male terminalia be teased open, thus allowing 

examination of these structures and identification of the 

species without need of dissection.

In the species’ descriptions, paired structures are described in the singular except where the context makes this 

inappropriate.

Acknowledgments

Although many specimens examined for this study are 

in the National Museum of Natural History, Smithsonian 

Institution, Washington, D.C. (USNM), we also borrowed 

and studied or cited numerous specimens that are deposited in the following museums: 

ANSP Academy of Natural Sciences of Philadelphia, Pennsylvania

CAS California Academy of Sciences, San Francisco

CSCA California State Collection of Arthropods, 

Sacramento

CNC Canadian National Collection, Ottawa, 

Ontario

DEBU University of Guelph Insect Collection, 

University of Guelph, Guelph, Ontario, 

Canada

MCZ Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts

WSU Maurice T. James Collection, Washington 

State University, Pullman

H. B. Williams (deceased) prepared the distribution 

maps, and Young Sohn produced the habitus illustration 

(Figure 1) and inked all other line drawings. The plates 

were assembled by Karolyn Darrow, who also expertly 

photographed and assembled the plates of heads and 

FIGURE 1. Trixoscelis fumipennis Melander.
4 • smithsonian contributions to zoology

wings. For reviewing a draft of this paper, we thank Joel 

Kits, Kevin N. Barber, and Allen L. Norrbom. We are also 

grateful to David Challinor (deceased), former Assistant 

Secretary for Research, Smithsonian Institution, and Stanwyn G. Shetler, former Deputy Director of the National 

Museum of Natural History, for financial support to conduct fieldwork and study primary types through grants 

from the Research Opportunity Fund.

We also acknowledge and express thanks for the valuable contribution of Kevin N. Barber, who provided information on the Nearctic fauna and collecting insights for 

trixoscelidines, and of Andrej Woznica for insights on the 

Palearctic fauna, particularly the identity of T. frontalis. 

We acknowledge and thank Robert K. Robbins for patiently introducing us to the use of TNT.

Funding for this research project, especially fieldwork 

in southern California (2003), Texas (2004), Idaho, Oregon, and Washington (2006), and Alaska (2006) was 

provided largely by grants from the Biodiversity Program 

(Biological Surveys and Inventories, BSI), National Museum of Natural History, Smithsonian Institution (Lynne 

R. Parenti and George Zug, chairs). Fieldwork in Alaska 

in 2002 was supported by the Bateman Fund. Fieldwork in 

the George Washington Memorial Parkway (2006–2008) 

was supported by a grant from the National Park Service, 

and we especially thank Brent W. Steury for his assistance, 

facilitation, and support.

SYSTEMATICS

Genus Trixoscelis Rondani

Trixoscelis Rondani, 1856:13 [type species: Geomyza obscurella Fallén, by 

original designation]. —Melander, 1913a:169 [comments on Parodinia 

costalis and P. claripennis in Trixoscelis]; 1913b:296 [key]. —Curran, 

1934:372 [in key to genera of Chyromyidae]. —Melander, 1952:40 

[revision]. —Vockeroth, 1965:817–818 [Nearctic catalog]. —Steyskal, 

1971:10 [nomenclature]. —Sabrosky, 1999:315 [nomenclature].

Parodinia Coquillett, 1902:186 [type species: Parodinia cinerea Coquillett, 

by original designation]. —Malloch, 1913:274–276 [synonymy; discussion, key, relationship to Zagonia].

Zagonia Coquillett in Baker, 1904:27 [type species: Zagonia flava Coquillett, by original designation]. —Melander, 1913b:297 [diagnosis, distribution]. —Curran, 1934: 372 [in key to genera of Chyromyidae]. 

—Melander, 1952:39 [diagnosis, key]. —McAlpine, 1985:234 [synonymical notes, classification].

Spilochroa Williston, 1907:2 [type species: Heterochroa ornata Johnson, 

monotypy]. —Curran, 1934:372 [in key to genera of Chyromyidae]. —

Melander, 1952:40 [diagnosis, key, distribution]. —Wheeler, 1955:111 

[discussion, key to species]. —Vockeroth, 1965:817 [Nearctic catalog]. 

—Cogan, 1977:3 [synonymy]. —McAlpine, 1985:234 [synonymical 

notes, classification].

Siligo Aldrich, in Aldrich and Darlington, 1908:99 [type species: Siligo oregona Aldrich, by original designation]. —Melander, 1913b:297 [diagnosis, distribution, synonymy with Zagonia].

Diastata [in part] Meigen, 1830:94. Malloch, 1931:28 [synonymy; discussion, key to Spilochroa as subgenus]. —Malloch, 1933:214 [synonymy; 

discussion].

Diagnosis. Body generally light brown to 

dark gray microtomentose, pleural sclerites sometimes 

darker brown, somewhat shiny, brown spots present or 

absent at bases of setae, including scutellar setae, two to 

four rows of acrostichal setae varying in regularity; wing 

hyaline to heavily infuscated, costa with a break at end of 

subcosta; costal margin with a row of strong setae varying in number; antenna with scape and pedicel yellowish 

to brown, center of basal flagellomere yellow to mostly 

brown or black; gena moderately short to conspicuously 

high, gena-to-eye ratio 0.15 to 0.55.

Description. Body length 1.64–3.71 mm. 

Head: Eye round to oval, often higher than wide;

ocellar triangle light brown to gray microtomentose; frons 

bare, generally yellowish orange becoming darker dorsally, parafrons usually whitish-silver microtomentose; two 

strong, reclinate parafrontal setae; ocellar setae one strong

pair, positioned at level of or anterior to anterior ocellus, 

one additional posterior pair of shorter, weaker ocellar 

setae; one short cruciate postocellar seta; medial vertical 

seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent; occiput very narrow, 

gray dorsally, often becoming paler ventrally, microtomentose with one row of short dorsoclinate setulae; antenna 

with scape and pedicel yellowish to brown, center of basal 

flagellomere yellow to mostly brown or black; arista brown, 

with sparse hairs. Gena-to-eye ratio from 0.15 to 0.55, 

usually yellow or white, sometimes with a diffuse brown

spot at base of oral vibrissa, microtomentose, bearing one 

row of short ventroclinate setae along ventral edge in addition to one stronger convergent oral vibrissa; face usually 

white; palpus usually yellow, clypeus small indistinct, gray 

to brown.

Thorax: Mesonotum gray, yellowish or brown 

microtomentose, sometimes with brownish vittae along 

dorsocentral and acrostichal rows of varying intensity. Dorsocentral setae 5(2+3); acrostichal setae in two or four rows 

of varying regularity; apical scutellar setae often twice or 

more length of scutellum. Pleural sclerites sometimes distinctly darker than mesonotum, anepisternum mostly bare 
number 637 • 5

except for one strong seta on posterodorsal corner along 

with three to four much smaller setulae in cluster; katepisternum with two longer setae and several very short 

setulae along posterodorsal edge. Wing hyaline to heavily 

infuscated. Halter usually white. Leg color varying from all 

dark to all yellow, male often with swollen hind basitarsus, 

sometimes with other basitarsi swollen in addition; fore 

femur with row of longer setae along posterodorsal and 

posteroventral surfaces

Abdomen: Tergites generally brown to gray microtomentose, lightly and evenly setulose. Male terminalia: 

Tergite 6 reduced to thin strip; sternites 6, 7, and 8 fused 

and asymmetrical; epandrium generally rounded, capsulate; 

hypandrium Y-shaped with stem directed anteriorly; surstyli varying from reduced/absent to large, robust, curved; 

cerci usually reduced or absent; pre- and postgonites fused 

or separate, pregonite often with a row of setae along the 

ventral margin; aedeagus simple, strap-like to highly complex, trilobed, heavily sclerotized. Female terminalia: Spermathecae 3; tergite and sternite 7 often strongly fused to

form a ring but point of fusion weak in some species; sternite 8 may bear lateral setaceous lobe; epiproct and hypoproct often with two strong setae on one or both.

Biology. Information on the biology of Trixoscelis is virtually negligible, being limited, with the exception of one species, to general observations on the 

climate and biotopes where specimens have been collected 

(Cogan, 1971; Campobasso et al., 1999). The immature 

stages are completely unknown, and the only clue as to 

where these may be found are Collin’s (1943) and Skidmore’s (1962) reports of T. frontalis (Fallén) being bred 

from a thrush blackbird’s nest (Turdus merula L.) in England. More specimens have been collected in dry or arid 

zones throughout the world, and certainly in this study 

of the Nearctic fauna we have discovered far greater species diversity in the comparatively arid West. This seeming 

preference for aridity is a pattern elsewhere in the worldwide distribution of Trixoscelis (Cogan, 1971). Kevin 

Barber (pers. comm.) has often observed large numbers of 

T. fumipennis in eastern Canada in areas with short grassy 

vegetation and sandy soils.

Phylogenetic Considerations. A detailed, species-level phylogeny is beyond the scope of this 

paper, especially as Trixoscelis is essentially found worldwide and herein we focus on the Nearctic fauna. Our intent here is to present evidence and an analysis of that 

evidence in an attempt to determine intermediate clusters 

of taxa such as species groups within Trixoscelis.

Recent classifications of Heleomyzidae (McAlpine, 

1985, 2007) place Trixoscelis in the subfamily Trixoscelidinae, tribe Trixoscelidini. We accept this classification and used it as a guide for selecting outgroups. Determining the outgroup(s) turned out to be as challenging as 

discovery of evidence used in the species group analysis. 

As noted previously, we initially studied the so-called genera Spilochroa and Zagonia as potential outgroups for a 

cladistic analysis of species groups within Trixoscelis but 

soon discovered that both putative genera represented taxa 

within the overall generic continuum of Trixoscelis. This 

continuum was especially evident in structures of the male 

terminalia, which for all three previously recognized genera 

are very similar, essentially representing variations on the 

same theme. Thus we confirm here Cogan and McAlpine’s 

synonymy of Spilochroa and Zagonia with Trixoscelis and 

the Nearctic species of these taxa are treated herein.

We then searched more broadly within the higher 

classification for outgroups, starting with Paratrixoscelis

Papp (we examined P. oedipus Becker), and soon discovered that this genus too is clearly within Trixoscelis, appearing in the majority of trees as the sister group to the 

fumipennis species group. Not only is its generic status 

problematic but its suitability as an outgroup is clearly 

questionable. Although we are confident that Paratrixoscelis is a junior synonym of Trixoscelis, we will not formally revise its status until we have examined specimens 

of all three described species of Paratrixoscelis from Mongolia, which is beyond the scope of this revision. Finally, 

we examined genera in related tribes as outgroups, such as 

Fenwickia Malloch (we examined F. claripennis Malloch), 

Aneuria Malloch (A. bipunctata Malloch), and Xeneura 

Malloch (X. picata Hutton) in Fenwickiini and Waterhousea Malloch (W. cyclops Malloch) in Waterhouseiini. To 

root these genera, including Trixoscelis, we used Neossos

Malloch as the overall outgroup. Neossos (family Heleomyzidae; Cogan, 1977) was chosen based on its apparent 

close relationship to Trixoscelis (Melander, 1952). The 

tribes Waterhouseiini and Fenwickiini are in the subfamily Trixoscelidinae (McAlpine, 2007). With these genera 

as outgroups, we proceeded with the cladistic analysis. 

McAlpine (1985) has placed the genus Stuckenbergiella

in Trixoscelidini, but the male is unknown so we did not 

include it in this analysis.

Trixoscelis, including Paratrixoscelis, is apparently a 

monophyletic genus based on the following synapomorphies: gonites well developed and separate from the hypandrium (nos. 14 and 15 below), cerci in male reduced or 

absent (no. 13), female seventh tergite and sternite fused 

or nearly fused in many taxa (no. 21), ocellar setae inserted anterior to the level of the anterior ocellus (no. 4) 

and dorsocentral setae 5(2+3) (no. 5).
6 • smithsonian contributions to zoology

With the phylogenetic background for further study of 

Trixoscelis within the tribe Trixoscelidini, subfamily Trixoscelidinae, established and the monophyly of the genus 

documented, we now proceed with the cladistic analysis 

and resultant relationships among the included species, but 

with a few explanatory remarks first. In the presentation 

on species group relationships that follows, the characters 

used in the analysis are listed first. The cladogram (Figure 

2) is the primary mode to convey these relationships. In 

the discussion of character data, a “0” indicates the plesiomorphic state, while a “1” or “2” indicates the progressively more derived states. Question marks in the matrix 

indicate unclear or unavailable data. Multistate characters 

6, 8, 13, 15, and 21 were treated as nonadditive (dash). 

The numbers used for characters in the presentation are 

the same as those on the cladogram, and the sequence is 

the same as noted in the character matrix (Table 1).

Characters Used in the Analysis

Head

1. Number of frontal setae: 2 pairs (0); 3 pairs (1).

2. Genal height: short, less than 0.15–0.28 as high as 

eye (0); high, 0.33 to over 0.50 as high as eye (1).

3. Face shape in lateral view: normal, concave (0); 

somewhat convex (1).

4. Position of ocellar setae: Inserted behind level of 

anterior ocellus (0); inserted in front of or level 

with anterior ocellus (1).

Thorax

5. Number of pairs of dorsocentral setae: 4 (0); 5 (1) 

(a synapomorphy for Trixoscelis).

6. Male basitarsi: hind basitarsus not enlarged at all 

(0); hind basitarsus moderately but obviously swollen (1); hind basitarsus widely swollen (2).

7. Male mid and fore basitarsi: not enlarged at all (0); 

swollen, if only slightly (1).

8. Wing: hyaline (0); partially maculate (1); predominately dark with round hyaline spots (2).

9. Number of setae at costal break: 2 (0); 1 (1) (a synapomorphy for Waterhouseiini and Fenwickiini).

10. Preapical dorsal tibial seta: present (0); absent (1).

Abdomen (Male)

11. Epandrium: large, robust in relation to the rest of 

the abdomen (0); smaller, less obvious in undissected specimens (1).

12. Number of surstyli: 1 pair (0) (In Neossos the surstyli are bi-lobed but not truly separate (Gilbert 

and Wheeler, 2007)); 2 pairs (1) (an autapomorphy 

for Fenwickiini).

13. Surstylus: large, strong, may be curved, with 

strong setae (0); small in relation to epandrium, 

often subtriangular, setae finer (1); reduced or absent (2) (an autapomorphy for the T. nuda species 

group).

14. Condition of gonites: fused with hypandrium, appearing only as small lobes with one or two setae 

on each (0); distinctly separated from hypandrium, 

variously shaped, pre- and postgonites distinct (1).

15. Postgonite: apparently absent (0); a simple, variously shaped lobe, armed with only a few weak 

setulae (1); a robust, curving lobe on the dorsal 

margin of the pregonite, armed with one strong 

spicule (2) (an autapomorphy for the T. fumipennis

species group).

16. Distiphallus: variously sclerotized, complex, with 

one to several flaps or lobes distally (0); a completely sclerotized strap-like structure, triangular 

or somewhat rectangular in form (1) (an autapomorphy for the T. nuda species group).

17. Distiphallus: without spicules on the distiphallus 

(0); armed with several strong spicules on the dorsal midshaft (1) (an autapomorphy for T. plebs, 

T. nitidiventris, and likely many more Palearctic 

species based on illustrations (Hackman, 1970)).

18. Cerci: well developed (0); reduced or absent (1) (an 

autapomorphy for Trixoscelis).

Abdomen (Female)

19. Appendages of eighth sternite: with lateral lobes 

(0); lateral lobes lacking (1).

20. Sclerotization of spermathecal ducts: not sclerotized (0); partially sclerotized (1).

21. Condition of seventh sternite and tergite: separate 

(0); fused with an evident suture (1); strongly fused 

(2) (derived states 1 and 2 are autapomorphies for 

Trixoscelis).

22. Shape of eighth sternite: lacking a notch (0); 

notched anteriorly (1).

23. Shape of spermathecae: spherical or conical (0); 

long, narrow (1).

Analysis and Results. Using the heuristic 

“traditional search” option in TNT (Goloboff et al., 2003, 

2008), 196 cladograms were generated from the analysis 

of the 23 characters. The cladograms have a length of 51 

steps. The matrix was then subjected to implied weighting 

with a K value of three, which further reduced the number 

of cladograms to 157. With our focus on species group 
number 637 • 7

FIGURE 2. Consensus cladogram depicting hypothetical cladistic 

relationships among species groups of Trixoscelis. A filled square is 

a nonhomoplasious synapomorphy; an open square a homoplasious 

synapomorphy; the top number is the character; and the bottom 

number is the character state.

Neossos

Waterhousea

Fenwikia

Aneuria

Xeneura

T. barberi

T. claripennis

T. flavens

T. flavida

T. lagunaensis

T. nitidiventris

T. plebs

T. signifera

T. annetteae

T. arnaudi

T. cinerea

T. coloradensis

T. crepida

T. flava

T. flavicornis

T. kernensis

T. litorea

T. melanderi

T. nuda

16

2

15

1

1

1

10

1

23

1

2

1

8

1

20

1

16

0

23

1

6

1

23

1

20

1

8

2

21

1

16

1

15

1

13

2

2

1

6

1

17

1

21

2

19

0

18

0

14

0

13

0

12

1

11

0

9

1

5

0

4

0

1

1

18

1

Paratrixoscelis

T. albibasis

T. bajaensis

T. buccata

T. costalis

T. deserta

T. desertensis

T. fumipennis

T. gigapeza

T. granditarsa

T. nevadensis

T. nigripeza

T. ornata

T. punctipennis

T. pygochroa

T. polita

T. suffusa

T. triplex

T. tumida

21

0

15

1

8

0

6

1

2

1

21

1

21

1

15

1

8

0

3

1

6

1

8

0

23

1

3

1

6

2

2

1

8

0

7

1

22

1

21

1

8

2

13

0

6

0

T. bifurcata

15

2

11

0

8

1
8 • smithsonian contributions to zoology

clusters, we then produced a strict consensus tree from 

the pool of 157 cladograms (Figure 2), collapsing some 

nodes, especially in some species of the T. fumipennis species group. Mapping of characters on trees was done with 

WinClada software (Nixon, 1999–2002) with the “slow 

optimization.”

We separate the species of Trixoscelis into three species groups of which two (the fumipennis and nuda groups) 

are monophyletic. The third group, our so-called claripennis group, is obviously not monophyletic but is retained 

as a loose assemblage of species that cannot be placed in 

the morphologically distinct fumipennis group. We do this 

for convenience but also because there are large numbers 

of Old World species (certainly more than has been found 

thus far in the New World) that remain undescribed and 

unplaced into species groups. Their addition may result 

in modified topologies, including an enlarged and more 

heterogeneous fumipennis group.

The nuda species group, including T. annetteae, T. arnaudi, T. cinerea, T. coloradensis, T. crepida, T. flava, 

T. flavicornis, T. kernensis, T. litorea, T. melanderi, and 

T. nuda, share a high gena; a simple, strap-like distiphallus; separated pre- and postgonites that are simple, lobelike structures; and pregonites that bear strong setae. This 

group, to date, is known only from North America and 

includes the two species previously placed in Zagonia, 

T. flava, and T. flavicornis.

The T. claripennis group, which we acknowledge is 

an assemblage of convenience, not being monophyletic, 

includes T. barberi, T. claripennis, T. flavens, T. flavida, 

T. lagunaensis, T. nitidiventris, T. plebs, T. signifera, and 

a host of Palearctic and Afrotropical species. Species of 

this group have a short gena; a multilobed, complex, and 

heavily sclerotized distiphallus; a postgonite that is absent 

or fused to the pregonite; and a pregonite that is simple 

and bears setae along the ventral margin. Although we 

have recognized the T. claripennis group as distinct from 

the T. fumipennis group, in many of the parsimony cladograms, there was some merging of these two groups into a 

single assemblage.

Finally, the large, apparently monophyletic T. fumipennis group has a generally short gena, a heavily sclerotized and complex distiphallus, and fused gonites with 

a variously strong spicule directed posteriorly on a thin, 

curved, dorsal lobe. Species of this group also often exhibit a maculation pattern in the wing. This group includes a number of Palearctic and Afrotropical species 

along with T. albibasis, T. bajaensis, T. bifurcata, T. buccata, T. costalis, T. deserta, T. desertensis, T. fumipennis, 

T. gigapeza, T. granditarsa, T. nevadensis, T. nigripeza, 

TABLE 1. Matrix of characters and taxa used in the cladistic 

analysis of Trixoscelis. Numbers for characters correspond with 

those used in the text. Question marks in the matrix indicate 

unclear or unavailable data.

Taxa 0000 000001 11111111 12222

Character Number 1234 567890 12345678 90123

Neossos 1001 100000 10111200 10000

Waterhousea 1000 000011 1011 ? 001 ? ????

Fenwickia 1000 000010 01000000 10000

Aneuria 1000 000210 01000000 10000

Xeneura 1000 000210 01000000 ? ????

Paratrixoscelis 0001 110000 00011001 00000

T. albibasis 0001 100200 00012001 00110

T. bajaensis 0001 100100 00012001 ?? ???

T. bifurcata 0001 110100 00012001 00200

T. buccata 0101 100100 00012001 00?00

T. costalis 0001 100100 00012001 00100

T. deserta 0001 100100 00012001 00200

T. desertensis 0001 100100 00012001 ?? ???

T. fumipennis 0001 100100 00012001 00200

T. gigapeza 0111 121000 00012001 00101

T. granditarsa 0111 121000 00011001 00201

T. nevadensis 0011 100000 00012001 00200

T. nigripeza 0001 111000 00012001 ?? ???

T. ornata 0001 100200 00012001 00110

T. polita 0001 100200 00012001 00110

T. punctipennis 0001 100200 00012001 00110

T. pygochroa 0001 100100 00012001 00200

T. suffusa 0001 100100 00012001 00200

T. triplex 0001 100000 00012001 00200

T. tumida 0101 121000 00012001 00200

T. barberi 0001 110000 10110001 ?? ???

T. claripennis 0001 110000 10110001 00200

T. flavens 0101 100000 10110001 00?01

T. flavida 0001 110000 10110001 00200

T. lagunaensis 0001 110000 10110001 00200

T. nitidiventris 0001 100000 10110011 00200

T. plebs 0001 100000 10110011 00200

T. signifera 0001 110100 10110001 00200

T. annetteae 0101 100000 10211101 10100

T. arnaudi 0101 100000 10211101 10100

T. cinerea 0101 100000 10211101 10100

T. coloradensis 0101 100000 10211001 11100

T. crepida 0101 100000 10211101 10100

T. flava 0101 110000 10211101 10101

T. flavicornis 0101 100000 10211101 11101

T. kernensis 0101 100000 10211101 10100

T. litorea 0101 100000 10211101 10100

T. melanderi 0101 100000 10211101 10100

T. nuda 0101 100000 10211101 10100
number 637 • 9

T. ornata, T. polita, T. punctipennis, T. pygochroa, T. suffusa, T. triplex, and T. tumida from the Nearctic Region. It also includes all four species previously placed in Spilochroa from the Neotropical Region (Gill, 1968).

Key to Nearctic Species of the T. fumipennis and T. claripennis Species Groups

1. Wing maculate, even if indistinctly and only anterior to vein R2+3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Wing entirely hyaline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2. Wing heavily maculate, mostly dark with hyaline spots [Figures 34, 41] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Wing variously maculate, dark markings on more extensive hyaline background [Figures 37, 40]. . . . . . . . . . . . . . . . . .6

3. Costal cell with a central dark spot [Figure 41]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Costal cell hyaline [Figure 34]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4. Abdomen shiny, dark brown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. polita (Malloch)

Abdomen microtomentose, gray with brown spots. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. ornata (Johnson)

5. Thorax with brown spots at bases of setae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. albibasis (Malloch)

Thorax entirely gray, without brown spots. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. punctipennis (Melander)

6. Gena moderately high to high, gena-to-eye ratio 0.28 or higher. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Gena moderately short, gena-to-eye ratio 0.26 or less. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7. Gena high, gena-to-eye ratio 0.40 or more [Figures 21, 22]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T. buccata Melander

Gena only moderately high, gena-to-eye ratio 0.28–0.33 [Figures 20, 24]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8. Thorax light brown with no vittae along dorsocentral, acrostichal, and supra-alar tracks; fore femur yellow, wing with 

only vague infuscation anterior to vein R2+3 [Figures 91, 92]; male epandrium yellowish. . . . . . . . . . T. suffusa Melander

Thorax light brown with distinct vittae along dorsocentral, acrostichal, or supra-alar tracks; fore femur dark, wing heavily infuscated [Figure 40], epandrium shiny black. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. fumipennis Melander

9. Thorax light brown with distinct vittae along dorsocentral, acrostichal, or supra-alar tracks, wing may be heavily 

maculate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Thorax gray microtomentose with indistinct brown vittae, wing only lightly maculate . . . . . . . . . . . . . . . . . . . . . . . . .11

10. Portion of vein M between crossveins r–m and dm–cu whitish [Figure 90]. . . . . . . . . . . . . . . . . . T. pygochroa Melander

Vein M between crossveins dark [Figures 37, 38]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. deserta Melander

11. Male hind basitarsus distinctly swollen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Male hind basitarsus not swollen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

12. Gena very narrow, only 0.15 eye height, male surstylus in posterior view not bifurcated [Figure 123]. . . . . . . T. signifera

Gena higher, 0.24–0.26 eye height, male surstylus in posterior view bifurcated [Figure 11]. . . . .T. bifurcata, new species

13. Acrostichal setae in 2 rows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. desertensis, new species

Acrostichal setae in 4 rows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. bajaensis, new species

14. Gena 0.12–0.25 eye height [Figure 143]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Gena at least 0.33 eye height [Figures 169, 171]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

15. Thorax usually light brown with vittae of varying intensity along dorsocentral and acrostichal tracks. . . . . . . . . . . . . 16

Thorax gray, sometimes with indistinct vittae between dorsocentral tracks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

16. Abdomen shiny brown or black. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. nitidiventris Melander

Abdomen gray to brown microtomentose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. triplex Melander

17. Fore femur yellow to very light gray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Fore femur black (rarely yellow in males) or dark gray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

18. Dorsal half of anepisternum distinctly brown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. nevadensis, new species

Anepisternum uniformly gray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. plebs Melander

19. Male hind basitarsus black, swollen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. nigripeza, new species

Male hind basitarsus yellow or brown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

20. Male basal flagellomere mostly to entirely bright yellow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. flavida Melander

Male basal flagellomere partly to mostly brown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

21. Male surstylus short, triangular [Figure 106]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. claripennis (Malloch)

Male surstylus long, narrow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1 0 • smithsonian contributions to zoology

22. Male surstylus curved upward [Figure 127]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T. lagunaensis, new species

Male surstylus nearly straight [Figure 105]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. barberi, new species

23. Fore femur black or brownish, male hind basitarsus greatly swollen. . . . . . . . . . . . . . . . . . . . . . . . . . T. tumida Melander

Fore femur usually light to dark yellow (rarely with some darkening on posterior surface, male hind basitarsus swollen 

or not. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

24. Mesonotum yellow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. flavens Melander

Mesonotum uniformly gray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

25. Basal flagellomere yellowish; acrostichal setulae in 2 rows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. nuda (Coquillett) species group (see separate key page 94)

Basal flagellomere black; acrostichal setulae in 4 rows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

26. Distiphallus complex, with 3 long, narrow arms [Figure 51] . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. gigapeza, new species

Distiphallus complex but with short, wider lobes [Figure 55]. . . . . . . . . . . . . . . . . . . T. granditarsa (Foster and Mathis)

The T. fumipennis Species Group

Diagnosis. The species of the fumipennis species group are distinguished from those of the other species groups by the following combination of characters.

Head: Gena short to moderately short, gena-to-eye 

ratio 0.15–0.33 but in several species up to 0.55.

Thorax: Wing maculate in most species to varying 

degree, some species with wing hyaline. 

Abdomen: Male terminalia: Epandrium generally

rather large and distinct in undissected specimens, light to 

very dark, microtomentose to shiny. Distiphallus heavily 

sclerotized and complex; gonites fused and bearing a variously developed spicule directed posteriorly, often on a thin, 

curved, dorsal lobe.

Remarks. This is the largest species group of 

Trixoscelis in North America and examination of illustrations (Hackman, 1970; Cogan, 1977; Collins, 1943; 

Woznica, 2000, 2007) of male terminalia of many Palearctic species indicates there are many more species of this 

group worldwide. The variously developed spicule on the 

gonites can be quite striking and seems to be unique to 

the subfamily Trixoscelidinae. The genus Paratrixoscelis,

described from Mongolia, seems to be closely allied to this 

species group and is likely a synonym of Trixoscelis.

Trixoscelis albibasis (Malloch), 

new combination

FIGURES 3–5, 34

Diastata (Spilochroa) albibasis Malloch, 1931:30.

Spilochroa albibasis. —Wheeler, 1955:112 [key, generic combination]. —

Vockeroth, 1965:817 [Nearctic catalog]. —Cole, 1969:433 [distribution, diagnosis].

Diagnosis. Body light brown microtomentose, pleural sclerites darker brown somewhat shining, 

brown spots at bases of most setae including scutellar 

setae, 4 rows of acrostichal setae, wing heavily infuscated, 

with hyaline spots, costal cell hyaline; antenna mostly yellow, center of basal flagellomere may be mostly brown, 

gena short, gena-to-eye ratio only 0.15.

Description. Body length 2.50–3.60 mm.

Head: Eye higher than wide; ocellar triangle light

gray microtomentose; frons bare, yellowish orange becoming darker dorsally, parafrons whitish-silver microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 1

strong pair, positioned at level of or anterior to anterior 

ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical 

seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent; occiput very narrow, 

gray dorsally, becoming white ventrally, microtomentose 

with 1 row of short dorsoclinate setulae; antenna mostly 

yellow, center of basal flagellomere sometimes mostly 

brown; arista brown, with sparse hairs. Gena short, genato-eye ratio 0.15, mostly white but with diffuse brown spot 

at base of oral vibrissa, microtomentose, bearing 1 row of

short ventroclinate setae along ventral edge in addition to a 

pair of stronger convergent oral vibrissae; face white; palpus yellow, clypeus small indistinct, gray.

Thorax: Mesonotum light brown microtomentose

with darker areas becoming light gray posterior to fourth 

dorsocentral seta including scutellum, light gray extends to 

at least the second abdominal tergite, brown spots at bases 

of most setae. Dorsocentral setae 5(2+3); acrostichal setae 

in 4 somewhat irregular rows; apical scutellar setae about 

twice length of scutellum. Pleural sclerites distinctly darker 

than mesonotum, anepisternum mostly bare except for one 

strong seta on posterodorsal corner along with 3–4 much 
number 637 • 1 1

smaller setulae in a cluster; katepisternum with 2 longer 

setae and several very short setulae along the posterodorsal edge. Wing (Figure 34) predominately infuscated, with 

round to oblong hyaline spots, one semicircular hyaline 

spot at wing tip between veins R4+5 and M, costal cell 

hyaline. Halter white. Legs entirely brownish yellow; fore 

femur with a row of longer setae along posterodorsal and 

posteroventral surfaces.

Abdomen: First and second tergites light gray microtomentose, remainder of abdomen dark brown, evenly 

setulose; tergites 3, 4, and 5 with 2 vague gray spots. Male 

terminalia (Figures 3, 4): Epandrium concolorous with remainder of abdomen; surstylus (Figure 3) long triangular 

evenly endowed with setae, pre- and postgonite fused but 

distinct, pregonite with a row of setae along ventral margin,

postgonite curved with one distal seta, (Figure 3), distiphallus 

complex with four narrow lobes (Figure 4). Female terminalia: Seventh sternite with a row of strong setae along 

posterior margin, distinct notch on anterior medial margin, 

seventh sternite and tergite fused but with distinct suture line; 

spermathecae spherical, ducts not sclerotized; eighth sternite 

lightly sclerotized, subtriangular with distinct lateral lobes 

each bearing several strong setae; hypoproct with 2 short, 

strong setae; epiproct very lightly sclerotized medially forming two triangles with 1 weak seta on tip of each.

Type Material. Malloch described T. albibasis from a single male specimen, the holotype, which is 

labeled “near Ledoux [handwritten] New Mexico/Aug 21/

Cockerell/TypeNo. 43126 U.S.N.M. [red]/Diastata (Spilochroa) albibasis Type [handwritten] Det J. R. Malloch 

[printed] Type [white label with black sub-border].” The 

holotype is directly pinned, is in good condition (abdomen 

removed and dissected with structures in an attached microvial), and is deposited in the USNM (43126).

Type Locality. United States. New Mexico. 

Mora: Ledoux (35°55.4′N, 105°21.7′W).

Other Specimens Examined. Neotropical: MEXICO. Baja California Sur. Los Barriles (23°39′N, 

109°42′W), 29–30 Apr 1979, M. Wasbauer (1♂; USNM).

Sonora. Bahia San Carlos (27°57.7′N, 111°01.5′W), 3 

Mar 1963, P. H. Arnaud, Jr. (1♂, 1♀; USNM).

Distribution (Figure 5). Nearctic: United 

States (New Mexico). Neotropical: Mexico (Baja California Sur, Sonora).

Remarks. This species can be readily distinguished from T. ornata and T. punctipennis by the light 

gray band from the fourth pair of dorsocentral setae to the 

second tergite of the abdomen.

Trixoscelis bajaensis Foster and Mathis, 

new species

FIGURES 6–9, 19–20

Diagnosis. Mesonotum gray, with brown vittae along the dorsocentral setae and the anterior intra-alar 

seta, 4 scattered rows of acrostichal setae, proepimeral 

seta present; wing vaguely maculate anterior to vein R4+5

and on crossvein dm–cu; antenna brown except for small 

area at base of arista yellow; vertex brown microtomentose; gena short, gena-to-eye ratio only 0.20; abdomen 

gray; male epandrium in undissected specimens bulbous, 

yellowish microtomentose in contrast to the rest of the 

abdomen.

Description. Body length approximately 

2.50 mm (measurements taken after dissection).

FIGURES 3–4. Structures of male terminalia of Trixoscelis albibasis (Malloch) (Mexico. Baja California Sur. Los Barriles [23°39’N, 

109°42’W]): (3) epandrium, surstylus, hypandrium, and gonites, lateral aspect; (4) distiphallus, ventral aspect. Scale = 0.1 mm.
1 2 • smithsonian contributions to zoology

Head (Figures 19, 20): Eye round; ocellar triangle 

gray microtomentose; frons bare, mostly brown, parafrons

white microtomentose; 2 strong, reclinate parafrontal setae; 

ocellar setae 1 strong pair, positioned at level of or anterior 

to anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; 

lateral vertical seta long, strong and divergent; occiput narrow, gray microtomentose dorsally becoming concolorous 

with gena ventrally, with 1–2 rows of short dorsoclinate setulae; antenna brown except for small area at base of arista 

yellow; arista brown, with sparse hairs. Gena short, genato-eye ratio 0.20, white microtomentose, bearing 1 row of 

4–5 short ventroclinate setae along ventral edge in addition

to a pair of strong convergent oral vibrissae; face white; 

palpus yellow, clypeus small indistinct, brown.

Thorax: Mesonotum gray, brown vittae along the 

dorsocentral setae and the anterior intra-alar. Dorsocentral

setae 5(2+3); acrostichal setae in 4 irregular rows; apical 

scutellar setae only twice length of scutellum. Mesonotum 

sparsely covered with minute setae. Anepisternum gray, 

mostly bare except for one strong seta on posterodorsal 

corner along with 3–4 much smaller setulae in a cluster; 

katepisternum with 2 longer setae and several very short 

setulae along the posterodorsal edge. Wing vaguely maculate anterior to vein R4+5 and on crossvein dm–cu. Halter 

white. Fore femur light brown, otherwise legs entirely yellow, fifth tarsal segment slightly darker; fore femur with a 

FIGURE 5. Distribution map for Trixoscelis albibasis (Malloch).
number 637 • 1 3

row of longer setae along posterodorsal and posteroventral 

surfaces.

Abdomen: Uniformly gray microtomentose except

epandrium yellowish-brownish microtomentose, extreme 

posterior edges of some sternites lighter, evenly setose. Male 

terminalia (Figures 6–8): Epandrium in undissected specimens yellow, distinctly in contrast to the uniformly gray 

abdomen; surstylus (Figures 6, 7) widely triangular, rather 

straight in lateral view, robust triangular in posterior view; 

pregonite and postgonite fused and trilobed (Figure 8) dorsal lobe long, thin, bearing a sharp re-curved seta distally,

medial lobe slightly curved, also bearing a recurved seta 

distally, ventral-most lobe simple; basiphallus long, narrow,

curving ventrally, distiphallus complex, with two strongly 

sclerotized areas and a thin distal strand. Female terminalia: 

Unknown.

Type Material. The holotype male is labeled “MEX[ICO]: B[aja]. Calif[ornia]. Sur Arroyo San 

Gregorio 13 km. (air) WNW La Purisima/24/25-IV-1983 

M. Wasbauer coll[ector]. malaise trap/HOLOTYPE ♂

Trixoscelis bajaensis Foster & Mathis CSCA [red].” The 

holotype is double mounted (glued to a cardboard triangle 

on its right side), is in excellent condition with structures 

of the male terminalia clearly visible, and is deposited in 

the CSCA. Paratypes are as follows:

MEXICO. Baja California Sur. Rancho Tablon, 

Guillermo Prieto (21 km SW; 27°50′N, 113°19′W; Malaise trap), 14–17 Apr 1983, M. S. Wasbauer (3♂; CSCA, 

USNM).

Sonora: Bahia San Carlos (27°57.7′N, 111°01.5′W), 3 

Mar 1963, P. H. Arnaud, Jr. (1♂; USNM).

Type Locality. Mexico. Baja California 

Sur: Arroyo San Gregorio (13 km WNW of La Purísima; 

26°13.6′N, 112°21.8′W).

Distribution (Figure 9). Nearctic: Mexico (Baja California Sur, Sonora).

Etymology. The species epithet, bajaensis, 

is of Latin derivation and refers to the type locality in 

Mexico.

Remarks. This species is remarkably closely 

allied with T. deserta and T. desertensis but differs in the 

characters of the male postabdomen.

FIGURES 6–8. Structures of male terminalia of Trixoscelis bajaensis Foster and Mathis: (6) epandrium and surstylus, lateral aspect; 

(7) same, posterior aspect; (8) gonite, lateral aspect. Scale = 0.1 mm.
1 4 • smithsonian contributions to zoology

Trixoscelis bifurcata Foster and Mathis, 

new species

FIGURES 10–13, 35

Diagnosis. Body gray, thorax with two brown 

vittae between dorsocentral setae and along postpronotal 

and notopleural line, 4 rows of acrostichal setae; wing infuscated anterior to vein R4+5, darker anterior to vein R2+3; 

antenna mostly brown, yellow only at base of basal flagellomere, especially on medial surface; vertex yellowish to 

brown microtomentose; gena-to-eye ratio 0.24–0.26; male 

epandrium in undissected specimens yellowish.

Description. Body length 2.96–3.00 mm; 

generally gray microtomentose.

Head: Eye higher than wide; ocellar triangle light 

gray microtomentose; frons bare, mostly brown becoming lighter anteriorly, parafrons whitish microtomentose; 

2 strong, reclinate parafrontal setae; ocellar setae 1 strong 

pair, positioned at level of or anterior to anterior ocellus, 1 

additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong and divergent; occiput gray microtomentose with 

2–3 rows of short dorsoclinate setulae; antenna mostly 

brown, yellow only at base of basal flagellomere, especially 

on medial surface; arista brown, with sparse hairs. Gena 

moderately short, gena-to-eye ratio 0.24–0.26, white microtomentose, bearing 1 row of 10–12 short ventroclinate 

setae along ventral edge in addition to a pair of stronger 

FIGURE 9. Distribution map for Trixoscelis bajaensis Foster and Mathis.
number 637 • 1 5

convergent oral vibrissae; face white; palpus yellow, clypeus small indistinct, gray.

Thorax: Mesonotum uniformly gray microtomentose with 2 brown vittae between dorsocentral setae and 

along postpronotal and notopleural line, sparsely covered 

with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae in 4 somewhat 

irregular rows; apical scutellar setae about twice length 

of scutellum. Anepisternum mostly gray with a brownish 

area under the setae, mostly bare except for one strong 

seta on posterodorsal corner along with 3–4 much smaller 

setulae in a cluster; katepisternum with 2 longer setae and 

several very short setulae along the posterodorsal edge. 

Wing (Figure 35) infuscated anterior to vein R4+5, darker 

anterior to vein R2+3. Halter yellow. Fore coxae grayish, 

fore femur uniformly gray, slightly swollen; all other femora and tibiae yellow, tarsi darker, male hind basitarsus 

slightly swollen; fore femur with a row of longer setae 

along posterodorsal and posteroventral surfaces.

Abdomen: Uniformly dark gray microtomentose

except extreme posterior edges of sternites lighter; evenly 

setose. Male terminalia (Figures 10–12): Epandrium in undissected specimens yellowish; surstylus (Figures 10, 11) 

robust, recurved in lateral view, bifurcated in posterior 

view, pre- and postgonite separate, pregonite as in Figure 

12, postgonite (Figure 12) long, thin, becoming triangular

FIGURES 10–12. Structures of male terminalia of Trixoscelis bifurcata Foster and Mathis (Mexico. Sonora. Bahia San Carlos): (10) epandrium, 

surstylus, gonites, distiphallus, lateral aspect; (11) surstyli, posterior aspect; (12) pre- and postgonites and hypandrium, lateral aspect. Scale = 

0.1 mm.
1 6 • smithsonian contributions to zoology

distally with 4–5 dorsally directed, short setae, distiphallus (Figure 10) short, complex, darkly sclerotized. Female 

terminalia: seventh sternite and tergite strongly fused; 

spermathecae rather bulbous; eighth sternite with two distinct setaceous lobes; hypoproct with 2 short strong setae; 

epiproct with 2 weak setae.

Type Material. The holotype male is labeled 

“MEX[ICO]: Sonora Bahia San Carlos 3-III-1963 P. H. 

Arnaud, Jr./HOLOTYPE ♂ Trixoscelis bifurcata Foster & 

Mathis USNM [red]/USNM ENT 00118094 [plastic bar 

code label].” The holotype is double mounted (glued on 

the right side to a paper triangle on a pin), is in excellent 

condition (abdomen removed and dissected; structures in 

an attached microvial), and is deposited in the USNM. 

Paratypes are as follows:

MEXICO. Baja California. Rancho San Ignacio (26 

km E Rosarito; 32°20.9′N, 117°02.5′W), 26–27 Mar 

1982, M. S. Wasbauer (1♂, 1♀; CSCA).

Sonora. Bahia San Carlos (27°57.7′N, 111°01.5′W), 3 

Mar 1963, P. H. Arnaud, Jr. (1♀; USNM).

UNITED STATES. California. Imperial: Ogilby Road, 

Chocolate Mountains (5 km S junction with highway; 

78; 33°28′N, 115°35′W; Malaise trap), 20–22 Mar 1978, 

P. Adams, J. Slansky, M. S. Wasbauer (1♂; CSCA). Riverside: Palm Springs (33°49.8′N, 116°32.7′W), 26 Dec 

1952, P. H. Arnaud, Jr. (1♂; USNM).

Type Locality. Mexico. Sonora. Bahia San 

Carlos (27°57.7′N, 111°01.5′W).

Distribution (Figure 13). Nearctic: Mexico (Baja California, Sonora), United States (California).

FIGURE 13. Distribution map for Trixoscelis barberi Foster and Mathis (squares), T. bifurcata Foster and Mathis (dots), T. coloradensis Foster 

and Mathis (triangle), and T. desertensis Foster and Mathis (star).
number 637 • 1 7

Etymology. The species epithet, bifurcata, is 

of Latin derivation and refers to the unusually bifurcated 

surstylus of this species.

Remarks. Externally, this species is unremarkable and would key to T. signifera. Examination of structures of the male terminalia, however, reveals a bifurcated 

surstylus and other differences that distinguish this species 

from T. signifera.

Trixoscelis buccata Melander

FIGURES 14–18, 21–22, 36

Trixoscelis buccata Melander, 1952:43. —Vockeroth, 1965:817 [Nearctic 

catalog]. —Cole, 1969:433 [distribution, diagnosis].

Diagnosis. Body light brown; 2 or 4 rows 

of acrostichal setae; wing infuscate at crossveins, darker, 

smoky anterior to vein R4+5; basal flagellomere light brown 

to yellowish; vertex brown to blackish; gena high, genato-eye ratio 0.40–0.55; male epandrium in undissected 

specimens yellowish.

Description. Body length 1.64–3.04 mm; 

uniformly light brown microtomentose.

Head (Figures 21, 22): Eye higher than wide; ocellar triangle brown microtomentose; frons bare, yellow on 

ventral 2/3 brown to blackish dorsal 1/3, parafrons whitish microtomentose; 2 strong, reclinate parafrontal setae; 

ocellar setae 1 strong pair, positioned at level of or anterior 

to anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; 

lateral vertical seta long, strong and divergent; occiput gray 

microtomentose dorsal half, ventral half concolorous with 

gena, with 1–2 rows of short dorsoclinate setulae dorsally; 

antenna with basal flagellomere brown except area around 

arista yellow, scape and pedicel yellow; arista with sparse 

hairs. Gena-to-eye ratio 0.40–0.55, whitish microtomentose, bearing several short, scarcely discernible setulae ventrally and 2–3 slightly stronger setae posteriorly in addition 

to a pair of strong convergent oral vibrissae; face white; 

palpus yellow, clypeus small indistinct, white.

Thorax: Mesonotum uniformly light brown microtomentose, sparsely setulose. Dorsocentral setae 5(2+3); 

acrostichal setae in 4 irregular rows, may have 2 distinct 

rows plus a few scattered setulae forming the third and 

fourth rows; apical scutellar setae just over twice length of 

scutellum. Anepisternum mostly bare except for one strong 

seta on posterodorsal corner along with 3–4 much smaller 

setulae in a cluster with the larger seta; katepisternum with 

2 longer setae and one shorter one between them in a row 

along the posterodorsal edge. Wing (Figure 36) smoky hyaline, darker anterior to vein R4+5; junction of vein R1

 with 

costa and crossveins r–m and dm–cu also darkened. Halter 

white. Coxae, femora and tibiae yellow, tarsi darker; fore 

femur with a row of longer setae along posterodorsal and 

posteroventral surfaces, otherwise legs evenly setulose except for preapical tibial setae on all tibiae.

Abdomen: Uniformly light brown microtomentose

except posterior edges of sternites sometimes lighter, evenly 

setose. Male terminalia (Figures 14–17): Epandrium yellowish in undissected specimens, somewhat dorsally oblong; 

surstylus strong, distinct, subtriangular, with a medial curvature, endowed with many strong setae (Figures 14, 15); 

hypandrium ending in spatulate lobes on both sides posteriorly; pre- and postgonite fused, but postgonite (Figure 16) 

distinct and with terminal, sharp spine; pregonite spatulate,

endowed with three or four setae posteriorly; aedeagus as 

in Figure 14; distiphallus strongly black sclerotized in two 

portions, one portion simple, thin ribbon-like (Figure 17). 

Female terminalia: Seventh sternite and tergite fused into a 

ring; spermathecae spherical; eighth sternite with small lateral setaceous lobes; hypoproct armed with two quite short 

but strong setae, epiproct without a pair of distinct setae.

Type Material. Melander designated two 

specimens from “Sabino Canyon, near Tucson, Arizona, 

May 5, 1942” as the “Types” and eleven other specimens 

as paratypes. Of the two so-called “type” specimens one is 

a female and the other is missing both its head and abdomen. This makes it nearly impossible to define T. buccata

based on these types. Thus we herein designate one of the 

eleven so-called “paratypes” (= syntypes) that Melander 

had before him as the lectotype. The lectotype male of 

Trixoscelis buccata Melander, herein designated to stabilize and make more universal the use of this name, is 

the dorsal specimen of two flies on a double mount (vertically mounted on a minuten in a cardboard rectangle) 

that is labeled “UpStaAnaRiv Lost Creek 29/7/48 [29 Jul 

1948] CAL[IFORNIA. San Bernardino:] A. L. Melander/

PARATYPE Trixoscelis buccata Melander [yellow]/A. L. 

Melander Collection 1961 [green stippling on right side]/

LECTOTYPE ♂ Trixoscelis buccata Melander Foster & 

Mathis USNM/USNM ENT 00118095 [plastic bar code 

label].” The ventral specimen on the pin, a paralectotype 

♂, has had the abdomen removed and dissected, and the 

structures are in an attached microvial. The lectotype is deposited in the USNM. Other paralectotypes are as follows:

UNITED STATES. Arizona. Pima: Baboquivari 

Mountains (31°47.4′N, 111°35.2′W), 27 Apr 1947, A. L. 

Melander (2♂, 1♀; USNM); Sabino Canyon (31°52′N, 

111°27.4′W), 5 May 1942, A. L. Melander (2♀, 1 unknown sex [lacking head and abdomen]; USNM).
1 8 • smithsonian contributions to zoology

California. Riverside: Andreas Canyon (33°45.7′N, 

116°32.2′W), 1 Apr 1945, A. L. Melander (1♂, 1♀; USNM). 

San Bernardino: Mojave Desert, Thorn (34°28.6′N, 

117°16.6′W), 30 May 1944, A. L. Melander (2♀; USNM).

Colorado. El Paso: Manitou Springs (38°51.6′N, 

104°55′W), 18 Jun 1940 (not 16 Jun 1940, as Melander 

[1952:43] published), A. L. Melander (1♂, 1♀; USNM).

Type Locality. United States. California. 

San Bernardino: Upper Santa Ana River, Lost Creek 

(35°03.5′N, 119°21.8′W).

Other Specimens Examined. MEXICO.

Baja California Sur. Arroyo San Gregorio (13 km WNW 

of La Purísima; 26°13.6′N, 112°21.8′W), 24–24 Apr 

1983, M. S. Wasbauer (3♂, 1♀; CSCA); Guillermo Prieto (21 km SW; 27°50′N, 113°19′W; Malaise trap), 3–5 

Apr 1982, M. S. Wasbauer (1♀; CSCA); El Pescadero, 

Playa Los Cerritos (23°19.8′N, 110°10.6′W), 14–15 Apr 

1979, M. S. Wasbauer (1♀; CSCA); Los Barriles (23°39′N, 

109°42′W), 5–6 May 1979, M. S. Wasbauer (2♀; CSCA).

Sonora. Alamos (28°40′N, 110°22′W), 26 Feb 1963, 

P. H. Arnaud, Jr. (3♀; USNM).

UNITED STATES. Arizona. Cochise: Portal, Southwestern Research Station (8 km SW of Portal; 31°52.9′N, 

109°12.2′W; 1631 m; Malaise trap), 23 May–9 Jun 1967, 

1972, C. W. Sabrosky, W. W. Wirth (5♀; USNM); Ramsey 

Canyon (31°27.8′N, 110°17.4′W; 1585 m; 24 km S Sierra Vista), Huachuca Mountains, 12 Apr 1967, R. F. 

Sternitsky (1♀; CNC). Coconino: Flagstaff, Oak Creek 

Canyon, Sterling Canyon (35°01.5′N, 111°44.2′W; 1800 

m; riparian woods), 17–25 Jul 1979, S. Peck, J. Peck 

(1♂; DEBU); Flagstaff (16 km NW, San Francisco Mountains; 35°20.5′N, 111°41′W; 2895 m; spruce, fir, aspen 

meadow, Malaise trap), 18–24 Jul 1979, S. Peck (1♀; 

DEBU); Oak Creek Canyon (34°54.8′N, 112°28.1′W), 

21 Jun 1938, Christenson (1♂; USNM). Greenlee: Clifton, Hot Spring (33°04.8′N, 109°18.2′W), 27 Jun, H. S. 

Barber (1♀; USNM). Maricopa: Wickenburg (33°58.1′N, 

112°43.8′W), 18 May 1950 A. H. Sturtevant (1♀; 

FIGURES 14–17. Structures of male terminalia of Trixoscelis buccata Melander: (14) epandrium, surstylus, gonites, distiphallus, lateral aspect; 

(15) epandrium and surstyli, posterior aspect; (16) hypandrium and gonites, lateral aspect; (17) distiphallus, ventral aspect. Scale = 0.1 mm.
number 637 • 1 9

USNM). Yavapai: Prescott (34°32.4′N, 112°28.1′W), 11 

Nov 1950, A. H. Sturtevant (1♂, 1♀; USNM).

Colorado. Rio Grande: South Fork (37°40.2′N, 

106°38.4′W; 2440 m), 20 Jun 1972, W. W. Wirth (4♂, 

1♀; USNM).

New Mexico. Catron: Gila National Forest (Middle 

Fork of Gila River; 33°13.3′N, 108°14.6′W; riparian zone), 

29 May 1991, B. J. Sinclair (1♂, 3♀; CNC); Gila National 

Forest, Whitewater Canyon (33°21.6′N, 108°04′W), 30 May 

1991, J. E. Swann (2♂, 1♀; DEBU); Glenwood (33°19′N, 

108°53′W), 13 Jun 1950, A. H. Sturtevant (1♂, 1♀; 

USNM); Glenwood (8 km E; 33°19′N, 108°52.5′W), 24 Jun 

1953, W. W. Wirth (1♂; USNM); Luna (8 km W; 33°49.1′N, 

108°57.3′W; 2255 m), 9–14 Jul 1979, S. Peck, J. Peck (4♀; 

DEBU); Whitewater Canyon (33°21.6′N, 108°03.9′W; 

Malaise trap), 1 Jun 1972, W. W. Wirth (3♂, 2♀; USNM). 

Grant: Cherry Creek, Pinos Altos (32°51.8′N, 108°13.3′W), 

22 Jun 1953, W. W. Wirth (1♂; USNM); Gila National Forest near Gila River Forks (32°59.4′N, 108°33′W), 29 May 

1991, J. E. Swann (5♂, 2♀; DEBU); Gila National Forest, 

Lake Roberts (33°02′N, 108°10′W; pan traps), 28 May–5 

Jun 1991, J. E. Swann (17♂, 20♀; DEBU).

Texas. Brewster: Big Bend National Park, Dugout 

Wells (29°16.3′N, 103°08.1′W; 915 m), 13 May 1959, 

J. F. McAlpine (3♂; CNC).

Utah. Wasatch: Daniels Pass (40°17.8′N, 111°15.1′W; 

153 m), 9 Jul 1961, J. G. Chillcott (1♂, 1♀; CNC).

Distribution (Figure 18). Nearctic: Mexico (Baja California Sur, Sonora), United States (Arizona, 

California, Colorado, New Mexico, Texas, Utah).

FIGURE 18. Distribution map for Trixoscelis buccata Melander.
2 0 • smithsonian contributions to zoology

FIGURES 19–24. Photographs of heads: (19) Trixoscelis bajaensis, anterior aspect; (20) same, lateral aspect; (21) T. buccata, anterior aspect; 

(22) same, lateral aspect; (23) T. deserta, anterior aspect; (24) same, lateral aspect.
number 637 • 2 1

Remarks. The number of rows of acrostichal 

setulae is problematic as a reliable character for this species because some specimens appear to only have two 

rows, while others clearly have four. If there are only two 

clearly defined rows, then there are often a few other scattered setulae that form a vague third and fourth row of 

acrostichal setulae. The high, whitish gena and generally 

light color along with wing markings distinguish this species from most other congeners. Like other congeners, 

however, the wing markings can vary. We have seen specimens in which only crossvein dm–cu is clearly maculate.

Trixoscelis costalis (Coquillett)

FIGURES 25–28

Rhicnoessa costalis Coquillett, 1901:378.

Parodinia costalis (Coquillett). —Coquillett, 1902:187 [generic combination

in footnote]. —Malloch, 1913:276 [key, diagnosis].

Trixoscelis costalis (Coquillett). —Melander, 1913a:169 [synonymy with 

T. frontalis]. —Melander, 1913b:296 [key, generic combination]. 

—Melander, 1952:44 [compared to T. claripennis]. —Gill, 1968:7 

[Neotropical catalog, distribution]. —Cole, 1969:433 [note].

Diagnosis. Mesonotum gray with brown vittae along dorsocentral and acrostichal rows, sometimes 

continuing over the scutellum, pleural sclerites brown, in 

sharp contrast to mesonotum, 4 rows of acrostichal setae, 

proepimeral seta present; wing smoky brown anterior to 

vein R2+3 and rarely vaguely darker along crossveins and 

vein CuA1; antenna mostly light brown with yellowish 

areas on the flagellum; vertex gray microtomentose; gena 

short, gena-to-eye ratio only 0.15; abdomen mostly gray 

microtomentose, extreme lateral edges of tergites brown; 

male epandrium in undissected specimens large, light yellow microtomentose in contrast to the rest of the abdomen.

Description. Body length 1.69–3.50 mm.

Head: Eye higher than wide; ocellar triangle light

gray to brown microtomentose; frons bare, light brown becoming darker dorsally, parafrons silvery microtomentose; 

2 strong, reclinate parafrontal setae; ocellar setae 1 strong 

pair, positioned at level of or anterior to anterior ocellus, 1 

additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong and divergent;occiput rather narrow, gray microtomentose dorsally becoming concolorous with gena ventrally, with 1–2 rows of short dorsoclinate setulae; antenna 

mostly light brown with yellowish areas on the flagellum; 

arista brown, with sparse hairs. Gena short, gena-to-eye 

ratio 0.15, whitish microtomentose, bearing 1 row of 2–3

short ventroclinate setae along ventral edge in addition to a 

pair of strong convergent oral vibrissae; face white; palpus 

yellow, clypeus small indistinct, brown.

Thorax: Mesonotum gray microtomentose, with

brown vittae along dorsocentral and acrostichal rows, 

sometimes continuing over the scutellum. Dorsocentral 

setae 5(2+3); acrostichal setae in 4 irregular rows; apical 

scutellar setae only slightly longer than scutellum. Mesonotum sparsely covered with minute setae. Anepisternum 

mostly bare except for one strong seta on posterodorsal 

corner along with 3–4 much smaller setulae in a cluster; 

katepisternum with 2 longer setae and several very short 

setulae along the posterodorsal edge. Wing smoky brown 

from anterior margin to vein R2+3 and rarely vaguely darker 

along crossveins and vein CuA1. Halter white. All coxae 

yellow, fore femur brown to black, slightly swollen, all 

other femora, tibiae and tarsi yellow; fore femur with a 

row of longer setae along posterodorsal and posteroventral 

surfaces.

Abdomen: Mostly gray microtomentose, extreme

lateral edges of tergites brown.

Male terminalia (Figures 25–27): Epandrium in undissected specimens yellow, distinctly in contrast to the gray 

abdomen, cercus uniquely distinct and narrow; surstylus 

(Figures 25, 26) long narrow and rather straight, with 

somewhat sharp triangular tip, armed with long, strong 

seta on anterior surface; pre- and postgonite fused (Figures 25, 27) small, bearing short, sharp spicule on the 

postgonite remnant; ventrally, bearing many long, strong 

ventrally directed setae; aedeagus robust, complex, not 

as strongly sclerotized as most other Trixoscelis (Figure 

25). Female terminalia: Seventh tergite and sternite forming strong, tight ring but with evident suture line, seventh 

sternite with row of 5–6 short, strong setae on posterior 

margin; spermathecae spherical; eighth sternite with weak, 

barely evident lateral lobes; hypoproct with 2 very short, 

strong setae, epiproct with 2 weak setae.

Type Material. Coquillett described T. costalis from two specimens from Tagus Cove, Albemarle Island (Galápagos Islands). One specimen labeled as “Type” 

in the USNM collection is labeled “Galapagos Isl[and] Albemarle [handwritten on white label]/Tagus Cove 3-23-

99 [handwritten on white label]/Type No. 4715 U.S.N.M. 

[red]/Rhicnoessa costalis [white label folded in half]/Parodinia costalis Coq. [white label with black border].” The 

specimen is missing; all that remains is the double mount 

and label. The second syntype is apparently lost.

The neotype male, herein designated, is labeled “ECUADOR: Galapagos Islands Isla Santa Fe, arid zone, 

10–50m, 4–6.iv.1989, Peck & Sinclair malaise (89–186) 

[white label]/NEOTYPE ♂ Rhicnoessa costalis Coquillett 
2 2 • smithsonian contributions to zoology

Foster & Mathis CNC [red label].” The neotype is double 

mounted (glued to a paper triangle), is in excellent condition, and is deposited in the CNC.

Other Specimens Examined. ECUADOR. 

Galápagos Islands. Española: Bahia Manzanilla (01°22.1′S, 

89°40.5′W; littoral zone; Prosopis and Cryptocarpus grove 

behind beach; dung trap, FIT, Malaise trap), 5–10 Jun 1985, 

S. Peck, J. Peck (1♂, 3♀; CNC). Floreana: Black Beach 

(30 km E; 01°14.2′S, 90°27′W; 120 m), 21–28 Mar 1989, 

S. Peck, B. J. Sinclair (7♂; CNC). Genovesa: Bahia Darwin 

(0°19.3′N, 89°57.3′W; 20 m; Bursera forest; Malaise trap), 

10 Jan–27 Mar 1992, S. Peck (4♂, 5♀; CNC); El Barranco 

(= Prince Philip’s Steps; 0°19.9′N, 89°57.6′W; arid zone), 

12–16 Nov 2001, B. J. Sinclair (3♂; CNC). Isabela: Cerro 

Azul (1 km NE near Iguana; 0°55′S, 91°24.5′W; 85 m; pan 

trap), 19–25 May 1991, J. Heraty (1♀; CNC). Marchena: 

Punta Espejo (0°18′N, 90°28.5′W; Bursera grove, arid 

zone), 11–24 Mar 1992, S. Peck (5♂, 2♀; CNC); SW Playa 

(0°18.3′N, 90°31.3′W; arid zone, beach forest, dung trap), 

11–23 Mar 1992, S. Peck (2♀; CNC). San Cristobal: Caseta 

(00°48′S, 89°24′W; 560 m; pampa; dung trap), 16–22 Feb 

1989, B. J. Sinclair (2♀; CNC); El Progreso (1 km E; 0°54′S, 

89°33′W; 380 m; agricultural zone), 14 Feb 1989, B. J. 

Sinclair (1♀; CNC). Santa Cruz: Academy Bay (0°44.9′S, 

90°18.5′W; arid zone and thornscrub), 10 May–3 Jun 1985, 

S. Peck, J. Peck (18♂, 18♀; CNC); El Puntudo (00°39′S, 

90°20.5′W; 650 m; Scaleia forest), 1–30 Mar 1989, S. Peck, 

B. J. Sinclair (1♂; CNC); Charles Darwin Research Station 

(0°44.5′S, 90°18.2′W; 10 m; arid zone), 1–30 Mar 1989, 

S. Peck (3♂; CNC). Santa Fe: (0°48.8′S, 90°02.1′W; arid 

zone; 10–50 m), 4–6 Apr 1989, S. Peck, B. J. Sinclair (1♂, 

5♀; CNC); sweeping Sea Lion Beach (0°48.2′S, 90°02.5′W; 

FIGURES 25–27. Structures of male terminalia of Trixoscelis costalis (Coquillett): (25) epandrium, surstylus, gonites, distiphallus, 

lateral aspect; (26) epandrium and surstyli, posterior aspect; (27) gonites, lateral aspect. Scale = 0.1 mm.
number 637 • 2 3

sweeping), 4 Apr 1989, B. J. Sinclair (2♀; CNC); Sea Lion 

Beach (0°48.2′S, 90°02.5′W; sea lion dung trap; littoral 

zone), 3–6 Jun 1989, B. J. Sinclair (4♀; CNC).

Distribution (Figure 28). Neotropical: Ecuador (Galápagos Islands). Although erroneously 

reported from Arizona (Coquillett, 1902), this species is 

known thus far only from the Galápagos Islands.

Remarks. Because the type specimen is destroyed and the status and location of the second syntype 

are unknown, it would have been impossible to confirm the 

validity of this species without the generous loan of CNC 

material collected by Peck and Sinclair. The specimens fit 

Coquillett’s original description (1901) and Malloch’s later 

treatment (1913) except for the color of the fore coxae and 

the number of dorsocentral setae, which was corrected by 

Malloch. Coquillett (p. 378) described the “coxae and front 

legs dark brown.” We have found that the fore coxae are 

consistently white. Because the nearly 100 specimens from 

the Galápagos generally fit the original description and we 

found no other species in the series, we have based our concept of this species on this new material.

Trixoscelis deserta Melander

FIGURES 23–24, 29–33, 37–38

Trixoscelis deserta Melander, 1952:44. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:433 [distribution, diagnosis].

FIGURE 28. Distribution map for Trixoscelis costalis (Coquillett).
2 4 • smithsonian contributions to zoology

Trixoscelis mohavea Melander, 1952:47. —Vockeroth, 1965:818 [Nearctic catalog]. —Cole, 1969:434 [distribution, diagnosis]. NEW 

SYNONYM

Diagnosis. Thorax light brown with vittae 

on mesonotum and diffuse brown strip on dorsal surface 

of anepisternum, 2 rows of acrostichal setae, proepimeral 

seta present; wing smoky brown, distinctly to vaguely 

darker brown anterior to vein R2+3 and vaguely darker 

along crossveins and vein CuA1; antenna nearly completely 

brown except for small area at base of arista yellow; vertex brown microtomentose; gena short, gena-to-eye ratio 

only 0.15–0.22; abdomen blackish; male epandrium in 

undissected specimens large, light brown-yellow microtomentose in contrast to the rest of the abdomen.

Description. Body length 2.49–2.75 mm.

Head (Figures 23, 24): Eye wider than high; ocellar triangle light gray to brown microtomentose; frons 

bare, light brown becoming darker dorsally, parafrons silvery microtomentose; 2 strong, reclinate parafrontal setae; 

ocellar setae 1 strong pair, positioned at level of or anterior 

to anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; 

lateral vertical seta long, strong and divergent;occiput 

rather narrow, gray microtomentose dorsally becoming 

concolorous with gena ventrally, with 1–2 rows of short 

dorsoclinate setulae; antenna nearly completely brown except for small area at base of arista yellow; arista brown, 

with sparse hairs. Gena short, gena-to-eye ratio 0.15–0.22, 

whitish-yellow microtomentose, bearing 1 row of 2–3 

short ventroclinate setae along ventral edge in addition to 

a pair of strong convergent oral vibrissae; face white; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum light brown microtomentose, darker between acrostichal setae and along the dorsocentral row of setae. Dorsocentral setae 5(2+3); acrostichal 

setae in 2 irregular rows; apical scutellar setae only twice 

length of scutellum. Mesonotum sparsely covered with 

minute setae. Anepisternum mostly bare except for one 

strong seta on posterodorsal corner along with 3–4 much 

smaller setulae in a cluster; katepisternum with 2 longer 

setae and several very short setulae along the posterodorsal edge. Wing (Figures 37, 38) smoky brown, distinctly 

darker brown anterior to vein R2+3 and vaguely darker 

along crossveins and vein CuA1

. Halter white to yellow. All 

coxae yellow, fore femur yellow to darker, grayish brown, 

slightly swollen, all other femora and all tibiae yellow, tarsi 

slightly darker; fore femur with a row of longer setae along 

posterodorsal and posteroventral surfaces.

Abdomen: Uniformly gray to blackish microtomentose except epandrium yellowish-brownish microtomentose, extreme posterior edges of sternites lighter, evenly 

setose. Male terminalia (Figures 29–32): Epandrium in 

undissected specimens yellow, distinctly in contrast to the 

uniformly gray abdomen; surstylus (Figures 29, 30) long robust, narrowing distally, slightly curved anteriorly in lateral 

view, somewhat long triangular in posterior view (Figure 

30), armed with long, strong seta on anterior surface; preand postgonite fused (Figures 31, 32) small, bearing short, 

sharp spicule dorsomedially on the postgonite remnant,

ventrally, a simple, rather large lobe bearing several long, 

strong posteroventrally directed setae; distiphallus thin, 

narrow, somewhat complex (Figures 29, 32). Female terminalia: Seventh tergite and sternite forming strong, tight ring; 

spermathecae conical with bulbous head (“ice cream cone” 

shaped); eighth sternite with small lateral lobe bearing only 

two strong setae; hypoproct with two short, strong setae, 

epiproct with only weak setulae.

Type Material. Melander described T. deserta

from a single male, the holotype, that is labeled “Borego 

[sic Borrego; 33°13.2′N, 116°20.1′W] CAL[IFORNIA. 

San Diego:], Palm Canyon, 3 May 1945, A. L. Melander/

HOLOTYPE Trixoscelis deserta Melander [red]/A. L. Melander Collection 1961 [green stippling on right side].” The 

holotype is double mounted (pinned upright on a minuten 

glued in a brown cardboard square), is in excellent condition, and is deposited in the USNM.

Melander described T. mohavea from four syntypes. 

We herein designate one of these syntypes as the lectotype. The lectotype male is labeled “MOJAVE DESERT, 

Piute Butte [Los Angeles: 34°39.5′N, 117°51′W], 12 V 44 

CALIF[ORNIA], A. L. Melander/HOLOTYPE Trixoscelis mohavea Melander [red]/A. L. Melander Collection 

1961 [green stippling on right side]/Trixoscelis mohavea 

Melander [handwritten]/LECTOTYPE ♂ Trixoscelis 

mohavea Melander Foster & Mathis USNM/USNM 

ENT 00118091 [plastic bar code label].” The specimen 

is double mounted (pinned ventrally with a minuten inserted in a small cardboard square), is in good condition 

(distal half of right wing missing), and is deposited in the 

USNM. We have also examined a female specimen that is 

labeled “ALLOTYPE,” although this was not published 

by Melander. The so-called allotype is labeled “MOJAVE 

DESERT, Big Rock Wash, 13 V 44 CALIF[ORNIA], A. L. 

Melander/ALLOTYPE Trixoscelis mohavea Melander 

[red]/A. L. Melander Collection 1961 [green stippling on 

right side].” This specimen is also in excellent condition. 

The two paralectotypes are males, are double mounted together on the same minuten, and are labeled “MOJAVE 
number 637 • 2 5

DESERT, Piute Butte, 12 V 44 CALIF[ORNIA]/PARATYPE Trixoscelis mohavea Melander [yellow]/A. L. Melander Collection 1961 [green stippling on right side].” 

Both specimens are in excellent condition. The dorsal 

specimen has had the abdomen removed and dissected 

with the parts stored in an attached microvial.

Type Locality. United States. California. San 

Diego: Borrego (33°13.2′N, 116°20.1′W).

Other Specimens Examined. MEXICO. Baja California: El Pescadero, Playa Los Cerritos 

(23°19.8′N, 110°10.6′W), 14–17 Apr 1979, M. S. Wasbauer (1♂, 4♀; CSCA).

UNITED STATES. Arizona. La Paz: Ehrenberg (16 km 

NE; 33°36.3′N, 114°31.5′W), 16 Apr 1969, R. R. Pinger 

(1♂; USNM). Mohave: Littlefield (36°53.1′N, 113°55.8′W), 

1 May 2002, D. Mathis and W. N. Mathis (3♂, 2♀; USNM).

FIGURES 29–32. Structures of male terminalia of Trixoscelis deserta Foster and Mathis: (29) epandrium, surstylus, gonites, hypandrium, and 

aedeagus, lateral aspect; (30) epandrium and surstyli, posterior aspect; (31) gonites and hypandrium, lateral aspect; (32) gonites and aedeagus, 

ventral aspect. Scale = 0.1 mm.
2 6 • smithsonian contributions to zoology

California. Contra Costa: Mitchell Canyon, north

base of Mount Diablo (37°56.5′N, 121°56.2′W; 300–500 

m), 26 Aug 1994, M. E. Erwin (5♂, 5♀; CSCA). Humboldt:

Garberville (south fork Eel River; 40°38.5′N, 124°18.7′W), 

7–8 Aug 1982, B. Phelps, M. S. Wasbauer (1♂, 1♀; CSCA). 

Imperial: Ogilby Road, Chocolate Mountains (5 km S junction with highway 78; 33°28′N, 115°35′W; Malaise trap), 

16–22 Oct 1977, M. S. Wasbauer (1♀; CSCA). Inyo: Death 

Valley, Saratoga Springs (35°40.9′N, 116°25.3′W), 30 May 

1953 (1♂; USNM); Death Valley (36°29′N, 117°06′W), Apr 

1948, R. Coleman (2♀; USNM); Fish Lake Valley (9.5 km 

S, 6.5 km E Oasis; 37°29.5′N, 117°54.9′W), 16 Mar–8 Aug 

1982, 1983, D. Giulliani (1♀; CSCA); Morning Star Mine 

(= “Morning Sun Mine”; 36°31.5′N, 117°47.7′W; 388.5 

m), 4–5 Jun 1977, D. Giulliani (3♂, 3♀; CSCA); Mt. Whitney Fish Hatchery (8 km NW Independence; 36°48.2′N, 

118°12′W), 28–29 Aug 1979, M. S. Wasbauer, P. Adams 

(2♂, 14♀; CSCA); Saline Valley (36°42.2′N, 117°48.9′W), 

5–6 May 1977, D. Giulliani (15♂, 20♀; CSCA). Los Angeles: La Crescenta, base of Eagle Canyon (34°23.5′N, 

118°23.3′W; 750–850 m), 26 Apr–26 Jun 1994, 2002, 

S. D. Gaimari (1♂, 6♀; CSCA); La Crescenta, Eagle Canyon (south base Mount Lukens; 34°15′N, 118°15′W; 600 

m), 30 Jun 1994, S. D. Gaimari (3♂, 1♀; CSCA). Nevada:

Grass Valley (39°13.1′N, 121°03.7′W; 760 m), 23 Jun 1979, 

M. S. Wasbauer, F. Hillerman (1♂, 2♀; CSCA). Placer:

Rocklin (6.5 km S; 38°47.3′N, 121°14.1′W; Malaise trap), 

2–4 Jun 1980, P. Adams, M. S. Wasbauer (1♂, 1♀; CSCA). 

Riverside: Indio (33°43.2′N, 116°13′W), 6 Aug 1949, E. R. 

Tinkham (1♂, 7♀; USNM); Thousand Palms (33°48.7′N, 

116°22.6′W), 25 Mar–24 Apr 1955, W. R. Richards (5♂, 

5♀; CNC); Thousand Palms, Willis Palms Oasis (33°49′N, 

116°23.6′W), 25 Mar–3 Apr 1955, W. R. Richards, W. R. 

M. Mason (3♂, 1♀; CNC); Palm Springs, Andreas Canyon (33°45.7′N, 116°32.2′W), 10 Apr 1955, W. R. Richards (1♂; CNC); Thermal (33°38.4′N, 116°08.4′W), 9 Apr 

1955, W. R. Richards (1♂; CNC); University of California, 

Riverside (33°58.5′N, 117°19.7′W, Malaise trap), 7–21 Jun 

1983, D. Yu (1♂; DEBU). Sacramento: Sacramento River 

Levee (38°36.3′N, 121°33.3′W), 5 Oct 1969, M. Wasbauer (1♀; CSCA). San Bernardino: Helendale (34°44.6′N, 

117°19.5′W), 18 May 1955 W. R. Richards, W. R. M. 

Mason (8♂, 14♀; CNC); Phelan (11.2 km E; Baldy Mesa 

Road; 34°26′N, 117°27′W), 15–31 May 1982, J. T. Huber 

(2♂; DEBU); Twenty-nine Palms (34°08.1′N, 116°03.3′W), 

4 May 1958, A. L. Melander (1♂; USNM); Victorville 

(34°32.2′N, 117°17.5′W), 2–24 May 1952, 1953, 1955, G. 

A. Marsh, W. R. M. Mason, R. O. Schuster, A. H. Sturtevant 

(5♂; USNM). San Diego: Warner Springs, Agua Caliente 

Creek (33°16.7′N, 116°43.2′W; 945 m), 23–25 Aug 1980, 

P. Adams, M. S. Wasbauer (1♂; CSCA); Tecate (32°34.6′N, 

116°37.7′W), 2 May 1966, R. Duke (1♀; USNM). San 

Luis Obispo: Montana de Oro State Park Dunes (5 km 

SW Los Osos; 35°15.8′N, 120°51.8′W), 16–17 Aug 1983, 

P. Adams, M. S. Wasbauer (1♀; CSCA). Santa Barbara: 

Colson Canyon Campground (24 km E Santa Maria; 

34°55.8′N, 120°12.7′W), 8 Aug 1983, P. Adams, M. S. 

Wasbauer (20♂, 21♀; CSCA); Davey Brown Campground 

(19 km NE Los Olivos; 34°45.5′N, 119°57.1′W), 10 Aug 

1983, P. Adams, M. S. Wasbauer (3♂; CSCA). Shasta: Redding (40°34.2′N, 122°22′W), 1–3 Jun 1979, 7 Jul 1979, T. 

R. Haig (6♂, 9♀; CSCA). Siskiyou: Fort Jones (41°36.5′N, 

122°50.5′W), 6–10 Jun 1979, F. D. Horn (4♂, 5♀; CSCA). 

Solano: Gates Canyon (38°22.9′N, 122°02.3′W; 250–500 

m), 23 Jul 1994, S. D. Gaimari (1♂, 1♀; CSCA). Ventura: 

Camarillo (34°13′N, 119°02.3′W; ex. walnut), 16 Sep 

1970, D. Buettner (5♀; CSCA).

Nevada. Clark: Red Rock Canyon (36°08.7′N, 

115°25′W), 11 May 2001, D. Mathis, W. N. Mathis (8♂; 

USNM). Nye: Mercury (36°39.6′N, 115°59.7′W), 13 Jun 

1965, H. or S. Stapin (5♂, 3♀; USNM).

Utah. Emery: Green River (38°59.7′N, 110°09.7′W), 

19 Jul 1988, D. Mathis, W. N. Mathis (1♀; USNM).

Wyoming. Big Horn: Red Gulch Road, Highway 14 

(44°31.7′N, 107°50′W; shell pan traps in barren area nr. 

cottonwoods), 5–19 Aug 1990, J. E. Swann (1♂; DEBU); 

Red Gulch Road, Highway 14 (44°31.7′N, 107°50′W; 

shell pan traps in grass hammock in desert area; cow 

dung), 5–19 Aug 1990, J. E. Swann (1♂; DEBU).

Distribution (Figure 33). Nearctic: 

Mexico (Baja California), United States (Arizona, California, Nevada, Utah, Wyoming).

Remarks. Examination of the male terminalia of T. mohavea reveals it to be identical to T. deserta. 

Although both species were described in the same paper, 

page precedence gives seniority to T. deserta. We have 

discovered considerable variation in body size and wing 

coloration. We have examined many specimens that are 

diminutive in size or in which the wing maculation is quite 

light and limited to the cells anterior to vein R2+3. Structures of the male terminalia, however, are identical with 

other specimens of T. deserta.

Trixoscelis desertensis Foster and Mathis, 

new species

FIGURES 13, 39, 42–45

Diagnosis. Mesonotum light brown, silvery on postpronotal and notopleural areas, 2 rows of 
number 637 • 2 7

acrostichal setae, proepimeral seta present; wing vaguely 

maculate anterior to vein R2+3 otherwise hyaline; antenna 

nearly completely brown except for small area at base of 

arista yellow; vertex brown microtomentose; gena short, 

gena-to-eye ratio only 0.20; abdomen blackish; male 

epandrium in undissected specimens large, light brownyellow microtomentose in contrast to the rest of the 

abdomen.

Description. Body length approximately 

2.50 mm (measurement of both specimens taken after 

dissection).

Head: Eye round; ocellar triangle light gray

to brown microtomentose; frons bare, yellow, becoming darker dorsally, parafrons silvery microtomentose; 2 

strong, reclinate parafrontal setae; ocellar setae 1 strong 

pair, positioned at level of or anterior to anterior ocellus, 1 

additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong and divergent;occiput narrow, gray microtomentose 

dorsally becoming concolorous with gena ventrally, with 

1–2 rows of short dorsoclinate setulae; antenna nearly completely brown except for small area at base of arista yellow; 

arista brown, with sparse hairs. Gena short, gena-to-eye 

ratio 0.20, white microtomentose, bearing 1 row of 6–8

short ventroclinate setae along ventral edge in addition to a 

pair of strong convergent oral vibrissae; face white; palpus 

yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum light brown, silvery on 

postpronotal and notopleural areas. Dorsocentral setae 

FIGURE 33. Distribution map for Trixoscelis deserta Melander.
2 8 • smithsonian contributions to zoology

FIGURES 34–41. Photographs of right wings, dorsal aspects: (34) Trixoscelis albibasis; (35) T. bifurcata; (36) T. buccata; (37) T. deserta (dark); 

(38) T. deserta (light); (39) T. desertensis; (40) T. fumipennis; (41) T. ornata.
number 637 • 2 9

5(2+3); acrostichal setae in 2 irregular rows; apical scutellar setae only twice length of scutellum. Mesonotum 

sparsely covered with minute setae. Anepisternum brown 

medially, silvery both dorsally and ventrally, mostly bare 

except for one strong seta on posterodorsal corner along 

with 3–4 much smaller setulae in a cluster; katepisternum 

with 2 longer setae and several very short setulae along 

the posterodorsal edge. Wing (Figure 39) vaguely maculate anterior to vein R2+3 otherwise hyaline. Halter white. 

All coxae, femora, tibiae and basal four tarsal segments 

yellow, fifth tarsal segment dark; fore femur with a row 

of longer setae along posterodorsal and posteroventral 

surfaces.

Abdomen: Uniformly gray microtomentose except

epandrium yellowish-brownish microtomentose, extreme 

posterior edges of sternites lighter, evenly setose. Male terminalia (Figures 42–45): Epandrium in undissected specimens yellow, distinctly in contrast to the uniformly gray 

FIGURES 42–45. Structures of male terminalia of Trixoscelis desertensis Foster and Mathis (California. Riverside: Palm Springs): 

(42) epandrium, surstylus, gonites, and aedeagus, lateral aspect; (43) gonites, lateral aspect California. Riverside: Barton Flats; 

(44) same, latero-oblique aspect California. Riverside: Barton Flats; (45) same, ventral aspect California. Riverside: Barton Flats. 

Scale = 0.1 mm.
3 0 • smithsonian contributions to zoology

abdomen; surstylus (Figure 42) short robust, narrowing 

distally, slightly curved anteriorly in lateral view, somewhat 

long triangular in posterior view; pre- and postgonite fused 

(Figures 43–45) bearing long, robust, sharp spicule on the

postgonite remnant, ventrally bilobed (Figures 43, 45), one 

lobe rather large, bearing two long, strong posteroventrally 

directed setae; aedeagus short, thin, weak, with a medial 

tuft of spicules (Figure 42). Female terminalia: Unknown.

Type Material. The holotype male is labeled 

“Barton Flats CAL[IFORNIA] 10/7/46 A. L. Melander./

PARATYPE Trixoscelis suffusa Melander [yellow]/A. L. 

Melander Collection 1961 [white label with green stippling 

on right third]HOLOTYPE ♂ Trixoscelis desertensis Foster 

& Mathis USNM [red]/USNM ENT 00118090 [plastic bar 

code label].” The holotype is double mounted (pinned with 

a minuten ventrally and mounted in a cardboard square), is 

in good condition (abdomen removed and dissected; structures in an attached microvial, right wing missing), and is 

deposited in the USNM. Paratype is as follows:

UNITED STATES. California. Riverside: Palm Springs 

(33°49.8′N, 116°32.7′W), 16 Mar 1954, A. L. Melander 

(1♂; USNM).

Type Locality. United States. California. San 

Bernardino: Barton Flats (34°10.4′N, 116°51.8′W).

Distribution (Figure 13). Nearctic: 

United States (California).

Etymology. The species epithet, desertensis, 

is of Latin derivation and refers to the desert habitat of the 

species and its apparent close relationship to T. deserta.

Remarks. This new species seems to be extremely close to T. deserta but differs in the morphology 

of the structures of the male terminalia.

Trixoscelis fumipennis Melander

FIGURES 1, 40, 46–50, 57–58

Trixoscelis fumipennis Melander, 1913a:168; 1952:46 [revision]. —Melander, 1952:46 [diagnosis, key]. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis (Figure 1). Thorax brown with 

lighter stripes, 4 rows of acrostichal setae; antenna yellow to brown; vertex light gray-silvery microtomentose, 

fronto-orbital area between base of antenna and eye margin with an orange spot only seen in some angles; wing 

heavily infuscated with dark and whitish areas; gena-toeye ratio 0.28–0.33; abdomen black, shiny; male epandrium in undissected specimens black, subshiny, enlarged, 

bulbous.

Description. Body length 2.30–2.75 mm; 

thorax brown, abdomen black.

Head (Figures 57, 58): Eye slightly wider than 

high, nearly round; ocellar triangle light gray microtomentose; frons bare, orange anteriorly becoming black dorsally 

around ocellar triangle, parafrons whitish microtomentose; 

2 strong, reclinate parafrontal setae; ocellar setae 1 strong 

pair, positioned at level of or anterior to anterior ocellus, 1 

additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong, and divergent; occiput very narrow, gray microtomentose with 1 row of short dorsoclinate setulae; antenna 

mostly brown on lateral surfaces, yellow on medial surfaces 

and around base of arista; arista brown, with sparse hairs. 

Gena-to-eye ratio 0.28–0.33, white microtomentose, bearing 1 row of 2–3 short ventroclinate setae along ventral edge 

in addition to a pair of strong convergent oral vibrissae; face

white; palpus yellow, clypeus small indistinct, dark yellow.

Thorax: Mesonotum light brown microtomentose

with slightly but distinctly darker lines between acrostichal 

setae extended to the scutellum and along the line of the 

dorsocentral setae, an additional darker line along the line 

of the intra-alar setae, sparsely covered with setae much 

shorter than the dorsocentral setae. Dorsocentral setae

5(2+3); acrostichal setae in 4 irregular rows; apical scutellar 

setae about twice length of scutellum. Anepisternum mostly 

bare except for one strong seta on posterodorsal corner 

along with 10–12 much smaller setulae in a cluster; katepisternum with 2 longer setae and several very short setulae 

along the posterodorsal edge. Wing (Figure 40) heavily infuscated, darkest anterior to vein R2+3 and along crossveins 

and veins R4+5 and CuA1, area within discal cell whitish. 

Halter white. Legs entirely yellow except fore femur light 

brown to black, fore tibia sometimes dark; fore femur with 

a row of longer setae along posterodorsal and posteroventral surfaces.

Abdomen: May be entirely black or basal four 

segments dark brown subshiny, remaining distal segments 

black, distal margins of tergites black, evenly setose. Male 

terminalia (Figures 46–49): Epandrium (Figures 46, 47) uniformly black, somewhat vertically oblong; surstylus strong, 

distinct, long triangular, with medial curvature, endowed 

with many strong setae; hypandrium ending in spatulate 

setaceous lobes on both sides posteriorly; pre- and postgonite fused but distinct, postgonite (Figure 49) with terminal,

pointed spine; pregonite spatulate, endowed with three or 

four setae posteriorly and some setulae; aedeagus (Figure 

48) dark sclerotized, distiphallus simple, thin ribbon-like. 

Female terminalia: Seventh sternite and tergite strongly
number 637 • 3 1

fused, forming tight ring; spermathecae conical; eighth sternite with small but distinct setaceous lobes; hypoproct with 

two short but strong setae; epiproct sclerotized in two triangles each with a moderately strong seta at the posteriorly 

directed apex. 

Type Material. The holotype female is labeled “Aweme, Manitoba, N. Criddle, VI 12 11/HoloTYPE 6018 [red]/TYPE Trixoscelis fumipennis Mel. [red; 

handwritten]/Trixosc[elis] fumipennis Mel. Typ. [handwritten]” The holotype is double mounted [glued on its 

FIGURES 46–49. Structures of male terminalia of Trixoscelis fumipennis Melander (Canada. Manitoba: Treesbank): (46) epandrium, cercus, 

surstylus, gonites, and aedeagus, lateral aspect; (47) epandrium and surstyli, posterior aspect; (48) aedeagus, lateral aspect; (49) gonites, lateral 

aspect. Scale = 0.1 mm.
3 2 • smithsonian contributions to zoology

right side to a paper triangle], is in excellent condition, 

and is deposited in the ANSP (6018). There are two female paratypes in the USNM. They are double mounted 

on paper triangles and are labeled “Aweme, Manitoba, 

N. Criddle, VI 12 11/PARATYPE Trixoscelis fumipennis

Mel. [red]/A. L. Melander Collection 1961 [white label 

with green stippling on right side].” One specimen is 

headless but is otherwise in moderately good condition; 

the other specimen is in good condition except all frontal 

setae are missing. There is one additional paratype (ANSP) 

that is labeled “Aweme, Manitoba, N. Criddle, VI 12 11/

Para-Type 6018.3 [blue].” The fourth and final paratype 

is deposited in the CNC and is labeled “Trixoscelis fumipennis Melander PARATYPE No. 2835 [yellow]\Trixoscelis fumipennis Cresson PARATYPE No. 2835 [two hatch 

marks crossing out the info on a yellow label]\Aweme, 

Manitoba, N. Criddle, VI 11[or 12?] 11\PARATYPE Trixoscelis fumipennis [blue].” This paratype is in poor condition with the head missing as well as all legs except one 

mid coxa and femur and one hind coxa, femur, and tibia.

Type Locality. Canada. Manitoba. Aweme 

(49°42.5′N, 99°36.2′W).

Other Specimens Examined. CANADA. 

Alberta. Delburne (52°11.9′N, 113°14.1′W), 9 Jul 1979, 

D. H. Pengelly (1♀; DEBU); Drumheller, 25 km SE, Hoodoos (hillside grasses, sweeping) (51°22′N, 112°32′W), 16 

Jul 1999, K. N. Barber (3♂; DEBU); Elkwater, Elkwater 

Park (49°39.6′N, 110°16.9′W), 26 May, 8 Jun–12 Jun 

1952, 1956, L. A. Komotopetz, O. Peck (3♀; CNC); Empress (50°57.3′N, 110°0.3′W), 7 Jun 1957, Brooks, LacNay 

(1♂; CNC); Frank (49°36.1′N, 114°24.5′W), 15 Jun 1962, 

W. R. M. Mason (1♀; CNC); Grassy Lake (49°49.6′N, 

111°42′W), 24 Jun 1974, J. F. McAlpine (1♂, 4♀; CNC); 

Lethbridge (49°41.6′N, 112°50.5′W), 5–7 Jul 1956, O. 

Peck (2♀; CNC); Manyberries (49°24′N, 110°41.7′W), 

4 Jun 1952, A. R. Brooks (1♂, 3♀; CNC); Medicine Hat 

(50°02.4′N, 110°40.6′W), 7–23 Jun 1927, 1952, A. R. 

Brooks, F. S. Carr (3♀; CNC); Onefour (49°07.2′N, 

110°28.2′W), 3 May 1956, O. Peck (1♂; CNC); Onefour 

(49°07.3′N, 110°28.2′W), 2 Aug 1980, G. Gibson (1♂; 

DEBU); Steveville (50°50.3′N, 111°36′W), 21 Aug 1957, 

A. R. Brooks, J. E. Brooks (1♂; CNC); Milk River Valley (8 km E Writing-on-Stone Provincial Park; 49°05′N,

111°38′W), 1 Aug 1980, G. Gibson (3♂, 1♀; DEBU).

British Columbia. Fife (49°04′N, 118°12′W; 8 km 

E), 8 Jun 1959, R. E. Leech (1♂; CNC); Lytton (40 km 

N; 50°31′N, 121°43′W; 600 m; alfalfa, sage, clover, and 

mustard), 13 Jun 2000, H. Goulet, Gillespie (2♂; DEBU); 

Lytton (50°14′N, 121°34′W; 200 m; alfalfa, sage, rose and 

cactus), 13 Jun 2000, H. Goulet, Gillespie (2♂; DEBU); 

Okanogan Valley near Osoyoos (49°02′N, 119°27′W), 

10 Jul 1980, S. A. Marshall (2♂, 1♀; DEBU); Oliver, 

McIntyre Creek (50°02′N, 118°33′W), 6 Jun 1959, R. E. 

Leech (3♀; CNC); Oliver (49°10.8′N, 119°33.9′W), 

14–25 May 1959, R. E. Leech, E. E. MacDougall (2♂, 

2♀; CNC); Osoyoos, Haynes Eco. Reserve (49°02′N, 

119°27′W; pan trap; Purshia/Aristida steppe), 20 May–14 

Jun 1987, G. G. Cannings (5♀; DEBU); Robson (49°20′N, 

117°41′W), 5 Jun 1952, H. R. Foxlee (1♀; CNC).

Manitoba. Aweme (49°42.5′N, 99°36.2′W), 12 Jun 

1916, N. Criddle (1♂, 1♀; USNM); Bald Head Hills 

(12 km W Glenboro; 49°40.9′N, 99°18.3′W), 1 Aug 

1983, K. N. Barber (1♂; DEBU); Stockton (49°35.3′N, 

99°27.2′W; 3.2 km W), 6 Aug 1958, R. B. Madge (1♀; 

CNC). Treesbank (49°39.9′N, 99°36.1′W), 12 Jun–23 Jul 

1915, N. Criddle, J. M. Aldrich (9♂, 7♀; USNM); Shilo 

(49°48.1′N, 99°38.5′W; 4.8 km S), 30 Jul 1958, R. L. 

Hurley (1♂, 1♀; CNC); Shilo (49°48′N, 99°38.6′W; 8 km 

SW), 8 Jun–22 Jul 1958, R. B. Madge, C. D. F. Miller, 

J. G. Chillcott (1♂, 5♀; CNC).

Nova Scotia. Camp Aldershot (45°04.6′N, 

64°29.8′W), Jul 1966, K. M. Evans (3♂, 2♀; CNC).

Ontario. Acorn Lodge (Highway 21, 0.7 km S Ausable River Cut; 43°13.1′N, 81°52.2′W; mowed grasses 

on stable sand, sweeping), 16 Jun 2000, K. N. Barber 

(3♂, 3♀; DEBU); Algonquin Provincial Park (45°50.2′N, 

78°25.8′W), 29 Jun 1958, T. H. Scholten (1♂; DEBU); 

Batchawana Bay Provincial Park (46°56′N, 84°33′W; 

grasses on sand near entrance, sweeping), 4 Jul 2000, 

K. N. Barber (3♂, 3♀; DEBU); Brockville, 1000 Islands 

Regional Airport (mowed grasses on stable sand, sweeping) (44°38′N, 75°44′W), 10 Jun 2004, K. N. Barber (3♂, 

3♀; DEBU); Cambridge, Kossuth Road next to golf course 

(mowed grasses on stable sand, sweeping) (43°27′N, 

80°19′W), 10 Jun 2007, K. N. Barber (3♂, 3♀; DEBU); 

Chapleau, Brownlee Cemetery (mowed grasses on stable 

sand, sweeping) (47°49′N, 83°24′W), 17 Jun 2004, K. N. 

Barber (3♂, 3♀; DEBU); Corkery, cemetery (45°16′N, 

76°06′W; mowed grasses on stable sand, sweeping), 25 

Jul 2007, K. N. Barber (1♂, 2♀; DEBU); Dunn’s Valley, 

Shaw Road, D. V. Cemetery (46°27′N, 83°36′W; mowed 

grasses on stable sand, sweeping), 6 Jul 2007, K. N. Barber 

(2♀; DEBU); Flinton, St. John the Evangelist RC Church 

(44°41′N, 77°12′W; mowed grasses on stable sand, sweeping), 9 Jul 2001, K. N. Barber (1♀; DEBU); Garden River 

Indian Reservation, Bell’s Point Campground (46°32′N, 

84°12′W; mowed grasses on stable sand, sweeping), 

25–26 Jul 2000, K. N. Barber (3♀; DEBU); Goulais River, 

Pine Shores Road, G. R. Cemetery (46°41′N, 84°25′W; 

mowed grasses on stable sand, sweeping), 30 Jun 2007, 
number 637 • 3 3

K. N. Barber (3♂, 3♀; DEBU); Grand Bend, Pinery Provincial Park (43°18.2′N, 81°45.4′W), 17 Jul 1982, K. N. 

Barber (1♂; DEBU); Guelph (43°32.2′N, 80°13.7′W), 19 

Jun 1981, M. Eymann (1♀; DEBU); Hamilton, Kinsmen 

Playground, Beach Boulevard (43°16′N, 79°46′W; mowed 

grasses on stable sand, sweeping), 13 Aug 2000, K. N. 

Barber (1♀; DEBU); Hawk Junction, Community Centre 

(48°05′N, 84°33′W; mowed grasses on stable sand, sweeping), 17 Jun 2004, K. N. Barber (2♀; DEBU); Hawk Junction, Pine Grove Cemetery (48°05′N, 84°33′W; mowed 

grasses on stable sand, sweeping), 17 Jun 2004, K. N. Barber (3♂, 3♀; DEBU); Huntsville (9.5 km E of junction of 

highways 11 and 60; 45°21′N, 79°06′W; mowed grasses 

on stable sand, sweeping), 7 Jul 2005, K. N. Barber 

(1♂; DEBU); Hwy 69, 4 km WSW Foot’s Bay (45°06′N, 

79°47′W; mowed grasses on stable sand, sweeping), 8 Sep 

2004, K. N. Barber (1♂, 1♀; DEBU); Iron Bridge (3.1 km 

S, Sunset Cemetery; 46°15′N, 83°11′W; mowed grasses on 

stable sand, sweeping), 1 Sep 2003, K. N. Barber (3♂, 3♀; 

DEBU); Manitoulin Island, Michaels Bay Park (45°36′N, 

82°06′W; mowed grasses on stable sand, sweeping), 30 

Aug 2004, K. N. Barber (3♂; DEBU); Manitoulin Island, Providence Bay, “The Country Corner” (45°40′N, 

82°16′W; mowed grasses on stable sand, sweeping), 30 Jul 

2004, K. N. Barber (3♂, 3♀; DEBU); Manitoulin Island, 

Little Current, Holy Trinity Angli. Cemetery (45°58′N, 

81°56′W; mowed grasses on stable sand, sweeping), 30 

Aug 2004, K. N. Barber (3♂, 3♀; DEBU); Manitoulin Island, Burpee Mills Cemetery (4.4 km W Poplar; 45°46′N, 

82°32′W; mowed grasses on stable sand, sweeping), 22 

Jul 2000, K. N. Barber (3♂; DEBU); Massey (46°12′N, 

82°04′W; railside grasses on stable sand, sweeping), 12 Jun 

2004, K. N. Barber (3♂, 4♀; DEBU); Maynard (44°43′N, 

75°34′W; cemetery, mowed grasses on stable sand, sweeping), 10 Jun 2004, K. N. Barber (5♂, 5♀; DEBU); Metcalfe 

(45°14.1′N, 75°28.3′W), 22 Jul 1993, B. E. Cooper (1♀; 

CNC); Midland (8 km S, Huronia Municipal Airport; 

44°41′N, 79°55′W; mowed grasses on stable sand, sweeping), 1 Sep 2003, K. N. Barber (3♂, 3♀; DEBU); Neys 

Provincial Park near Visitor Center (48°46′N, 86°37′W; 

mowed grasses on stable sand, sweeping), 25 Jun 2003, 

K. N. Barber (3♂, 3♀; DEBU); Ottawa, Mer Bleue Bog 

(45°24′N, 75°30′W), 14–24 Jun 1980, K. N. Barber 

(2♂, 8♀; CNC) (19♂, 28♀; DEBU); Ottawa (45°20′N, 

75°35′W; damp, second growth Acer Betula wood), 15 

Jun 1998, J. R. Vockeroth (1♂; CNC); Pancake Bay Provincial Park (46°56′N, 84°40′W; grasses on sand near picnic shelter, sweeping), 4 Jul 2000, K. N. Barber (3♂, 3♀; 

DEBU); Port Colburne, Lakeshore Road West (mowed 

grasses on stable sand, sweeping) (42°52′N, 79°16′W), 

14 Aug 2000, K. N. Barber (1♂, 3♀; DEBU); Prescott, 

1.4 km NW, MacIntosh Road opposite sand hills (mowed 

grasses on stable sand, sweeping) (44°43′N, 75°32′W), 10 

Aug 2000, K. N. Barber (3♂, 3♀; DEBU); Prescott, Sandy 

Hill Cemetery (44°43′N, 75°31′W; mowed grasses on stable sand, sweeping), 7 Jun 2004, K. N. Barber (5♂, 5♀; 

DEBU); Rutherglen (2.4 km E; 46°16′N, 79°00′W; grasses 

on disturbed sand hill, sweeping), 6 Jul 2001, K. N. Barber 

(1♂, 3♀; DEBU); Rydal Bank (6.6 km N, Sands Cemetery; 

46°23′N, 83°43′W; mowed grasses on stable sand, sweeping), 6 Jul 2007, K. N. Barber (1♂, 2♀; DEBU); Sault St. 

Marie, Pine Grove Cemetery (46°35′N, 84°16′W; mowed 

grasses on stable sand, sweeping), 1 Jul 2007, K. N. Barber (3♂, 3♀; DEBU); Sault St. Marie (12 km W Pointe 

des Chenes Park; 46°28′N, 84°31′W; mowed grasses on 

stable sand, sweeping), 18 Jun 2000, K. N. Barber (5♂, 

5♀; DEBU); Sault St. Marie (10 km W, airport road, airport entrance; 46°29′N, 84°29′W; mowed grasses, sweeping), 19 Jun 2000, K. N. Barber (5♂, 5♀; DEBU); Sault St. 

Marie (12 km W, CFS hanger opposite Pointe des Chenes 

Park; 46°28′N, 84°31′W; mowed grasses on stable sand, 

sweeping), 17 Aug 1999, K. N. Barber (1♀; DEBU); St. 

Joseph Island, Beech Beach (46°07′N, 83°53′W; mowed 

grasses on stable sand, sweeping), 9–23 Jul 2000, K. N. 

Barber (3♂, 4♀; DEBU); Thessalon, Peace Park (46°15′N, 

83°33′W; mowed grasses on stable sand, sweeping), 3 Jul 

2000, K. N. Barber (3♂, 3♀; DEBU); Thessalon, Lakeside 

Park (46°15′N, 83°34′W; mowed grasses on stable sand, 

sweeping), 3 Jul 2000, K. N. Barber (2♂, 3♀; DEBU); Walford (1.3 km W; Walford Protestant Cemetery; 46°12′N, 

82°14′W; mowed grasses on stable sand, sweeping), 6 Jul 

2001, K. N. Barber (3♂, 3♀; DEBU); Wawa (5 km S; Kinniwabi Pines Motel; 48°46′N, 86°37′W; mowed grasses 

on stable sand, sweeping), 17 Jun 2003, K. N. Barber 

(3♂, 3♀; DEBU); Webbwood, St. Lawrence Cemetery 

(46°15′N, 81°54′W; mowed grasses on stable sand, sweeping), 2 Sep 2002, K. N. Barber (2♀; DEBU); White River, 

“Black’s Cabin” (48°36′N, 85°15′W; mowed grasses on 

stable sand, sweeping), 14 Jun 2003, K. N. Barber (3♂, 

3♀; DEBU).

Quebec. M. Ste. Marie–Low (45°56.5′N, 75°52.7′W; 

550 m), 22 Jun 1965, J. R. Vockeroth (1♂; CNC).

Saskatchewan. Assiniboia (49°38′N, 105°59′W), 

15–25 Jun 1955, A. R. Brooks and J. R. Vockeroth (3♀; 

CNC); Cut Knife, Attons Lake (52°50′N, 108°51.7′W), 

30 May 1940, A. R. Brooks (5♀; CNC); Elbow (51°07′N, 

106°35′W), 3 Apr–12 Jul 1960, A. R. Brooks (3♂, 9♀; 

CNC); Grasslands National Park, Snake Pit Prairie Dog 

Town (49°07′N, 107°26′W), 7 Jun 1998, Christopherson, Raab (1♀; DEBU); Grasslands National Park, Larson 
3 4 • smithsonian contributions to zoology

Prairie Dog Town (49°07′N, 107°26′W), 12 Jul 1998, 

Christopherson, Raab (2♀; DEBU); Grasslands National 

Park, Monument Prairie Dog Town (49°07′N, 107°26′W), 

29 Jun 1998, Christopherson, Raab (1♀; DEBU); Grasslands National Park (49°07′N, 107°26′W), 05 Jun 1998, 

Christopherson (3♂, 2♀; DEBU); Grasslands National 

Park, Val Marie (49°14′N, 107°44′W; pitfall trap), 14 

Jul 1996 (5♂, 4♀; DEBU); Grasslands National Park, 

Val Marie, Prairie Dog RBT (49°14′N, 107°44′W), 22 

Jul 1997, S. A. Marshall, Finnamore (1♂, 2♀; DEBU); 

Lumsden (50°39′N, 104°52′W), 12 Jul 1958, A. and 

J. Brooks (2♀; CNC); Pike Lake (51°54′N, 106°49′W), 

24 May 1940, A. R. Brooks (2♂, 1♀; CNC); Saskatoon 

(52°07.8′N, 106°40.2′W), 13 Apr–4 Aug 1925, 1949, 

1950, 1957, A. R. Brooks, K. M. King (5♂, 9♀; CNC). 

Saskatoon, S. Saskatoon River valley, off Central Avenue 

(52°10′N, 106°43′W);prairie grasses, sweeping) 12 Jul 

1999, K. N. Barber (3♂, 1♀; DEBU); Saskatoon, 13 km 

S, Beaver Creek Conservation Area (51°58′N, 106°43′W), 

prairie grasses, sweeping) 12 Jul 1999, K. N. Barber (3♂, 

3♀; DEBU).

Yukon Territory. Klondike Loop (32 km N Whitehorse; 60°44′N, 135°03′W; dry slope, pan trap), 27 Jun–

14 Jul 1987, S. A. Marshall (1♀; DEBU).

UNITED STATES. Arizona. Coconino: Bonito Park 

(32 km N Flagstaff; 35°22.1′N, 111°33.3′W; 2125 m; 

sweeping ponderosa pine meadow), 5–8 Aug 1984, B. V. 

Brown (5♂; DEBU).

Colorado. El Paso: Colorado Springs (38°50′N, 

104°49.3′W), 20 Jun 1961, G. C. Steyskal (1♂; USNM). 

Jefferson: Golden, Mt. Vernon Canyon (39°41.7′N, 

105°12.6′W; 2200 m), 31 Jul 1961, C. H. Mann (1♀; 

CNC). Larimer: Estes Park (40°23.6′N, 105°29.6′W; 2290 

m), 20 Jul 1961, C. H. Mann (1♀; CNC).

Michigan. Alger: Au Train (3 km E; 46°25.8′N, 

86°50.2′W; short grasses on stable sand, sweeping), 23 Jul 

1999, K. N. Barber (1♂, 3♀; DEBU). Cheboygan: Huron 

Beach, 19 km NW, Highway 23 rest area (45°38′N, 

84°13′W; mowed grasses on stable sand, sweeping), 14 Jul 

2000, K. N. Barber (3♂, 3♀; DEBU). Chippewa: Riverview RV Campground, Bay Mills Indian Res. (46°27′N, 

84°35′W; mowed grasses on stable sand, sweeping), 29 Jul 

2000, K. N. Barber (2♀; DEBU). Crawford: Grayling (5 

km S, mile 252 on I-75, rest area; 44°39′N, 84°42.9′W), 

22 Jun 2003, K. N. Barber (2♂, 2♀; DEBU). Iosco:

Tawas Point State Park (44°15.2′N, 83°26.8′W; mowed 

grasses near lighthouse), 14 Jul 2000, K. N. Barber (3♀; 

DEBU). Livingston: E. S. George Reserve Field (42°36′N, 

83°55′W), 7 Aug 1958, A. Wenner (1♂; USNM). Sanilac: Forestville (mowed grasses on stable sand, sweeping) 

(43°39′N, 82°36′W), 14 Jul 2000, K. N. Barber (1♂, 

2♀; DEBU). St. Clair: Lakeport State Park (43°07.4′N, 

82°29.7′W; mowed grasses on stable sand, sweeping), 14 

Jul 2000, K. N. Barber (3♂, 3♀; DEBU).

Montana. Hill: Havre (43°33′N, 109°40.7′W), 13 Jun 

1916, J. M. Aldrich (5♀; USNM). Ravalli: Hannon Memorial Fishing access, Route 93 (45°58′N, 114°08.2′W), 

16 Jun 1996, R. S. Zack (1♂; WSU). Sheridan: Medicine 

Lake (48°30.1′N, 104°30.1′W), 9 Jun 1969, W. W. Wirth 

(1♀; USNM).

Nebraska. Cherry: Valentine (8 km S; 42°52′N, 

100°33′W), 14 Jul 1986, T. Henry, A. G. Wheeler (1♀; 

USNM). Garden: Lisco (11.3 km SE, Sand Hills; 41°20.2′N, 

101°57.3′W; 1100 m), 10 Jun 1994, S. D. Gaimari (1♀; 

CSCA). Thomas: Halsey (41°54.2′N, 100°16.1′W), 22 

Aug 1958, R. Henzlik (1♂; USNM).

New Mexico. Socorro: Water Canyon (32 km W Socorro; 33°51.4′N, 107°25′W; 2135 m), 28 Jun–7 Jul 1979, 

S. Peck, J. Peck (15♂, 9♀; DEBU). 

New York. St. Lawrence: Ogdensburg (6.4 km S, 

Eel Weir Road, Pine Hill Cemetery; 44°47′N, 75°29′W; 

mowed grasses on stable sand, sweeping), 11 Jun 2004, 

K. N. Barber (1♂, 2♀; DEBU).

North Dakota. Grand Forks: University Park 

(47°55.5′N, 97°03.7′W), Jun 1896, R. P. Currie (1♂, 1♀; 

USNM). Mountrail: White Lake (48°23.5′N, 102°27.8′W), 

8 Jun 1969, W. W. Wirth (1♂; USNM).

Oregon. Wallowa: Joseph (45°21.3′N, 117°13.8′W), 

13 Jun 1973, P. W. Oman, C. Musgrave (1♂, 1♀; DEBU).

Utah. Duchesne: Helper (32 km N; Avintaquin Campground; 39°53.1′N, 110°46.6′W), 18 Jul 1988, D. Mathis, 

W. N. Mathis (1♂; USNM).

Washington. Spokane: Dartford (47°47.1′N, 

117°25′W), 22–28 Jun, 6–12 Jul 1970, R. D. Gray (3♂, 

4♀; WSU); Liberty Lake (47°38.9′N, 117°05.5′W), 26 Jun 

1924, A. L. Melander (3♀; USNM). Whitman: Pullman 

(46°43.9′N, 117°10.8′W), Washington State University 

Golf Course, 7 Jul 1976, R. D. Akre (1♀; WSU).

Distribution (Figure 50). Nearctic: Canada (Alberta, British Columbia, Manitoba, Nova Scotia, 

Ontario, Quebec, Saskatchewan, Yukon), United States 

(Arizona, Colorado, Michigan, Montana, Nebraska, 

New Mexico, New York, North Dakota, Oregon, Utah, 

Washington).

Remarks. Considerable variation exists in the 

coloration of the basal flagellomere. It may be entirely 

yellow to entirely light brown. We have also noted some 

variation in the intensity of the wing maculation. Indeed, 

most specimens have a strong wing coloration easily seen 

with the naked eye. We have seen a very few specimens, 
number 637 • 3 5

however, with only very light maculation that are identical 

in all other respects to other specimens of T. fumipennis. A 

unique feature of this species is the orange coloration of the 

small space between the antennal base and the eye margin.

Trixoscelis gigapeza Foster and Mathis, 

new species

FIGURES 51–52

Diagnosis. Body gray microtomentose; 2–4 

rows of scattered acrostichal setae; wing hyaline; basal 

flagellomere mostly brown, area around base of arista 

yellow, scape and pedicel yellow; vertex brown laterad of 

ocellar triangle; gena high, gena-to-eye ratio 0.45–0.50; 

male epandrium in undissected specimens light brown, 

darker than remainder of abdomen, shiny.

Description. Body length approximately 

2.30–3.25 mm.

Head: Eye as high as wide; ocellar triangle gray 

microtomentose; frons bare, yellow, parafrons whitish microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior 

to anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; 

lateral vertical seta long, strong and divergent;occiput 

mostly gray microtomentose ventral 1/5 concolorous with 

gena, with 1–2 rows of short dorsoclinate setulae dorsally, 

one row of several setae ventrally; antenna with basal flagellomere mostly brown, area around base of arista yellow, 

scape and pedicel yellow; arista brown, with sparse hairs. 

Gena-to-eye ratio 0.45–0.50, white microtomentose, bearing several short, scarcely discernible setulae ventrally and 

2–3 slightly stronger setae posteriorly in addition to a pair

of strong convergent oral vibrissae, extreme ventral margin 

shiny, chitinous; face white, convex; palpus yellow, labellum as long as head, straight, clypeus indistinct.

Thorax: Mesonotum uniformly gray microtomentose, sparsely setulose. Dorsocentral setae 5(2+3); acrostichal setae in 2–4 irregular rows; apical scutellar setae 

twice length of scutellum. Anepisternum mostly bare except 

for one strong seta on posterodorsal corner along with 3–4 

much smaller setulae in a cluster with the larger seta; katepisternum with 2 longer setae and one shorter one between 

them in a row along the posterodorsal edge. Wing hyaline. 

FIGURE 50. Distribution map for Trixoscelis fumipennis Melander.
3 6 • smithsonian contributions to zoology

Halter white. Coxae, femora, and tibiae yellow, fore femur 

darker, tarsi brown, male basitarsus swollen, hind basitarsus largest; fore femur with a row of longer setae along 

posterodorsal and posteroventral surfaces, otherwise legs 

evenly setulose except for preapical tibial setae on all tibiae.

Abdomen: Uniformly gray microtomentose, evenly

setose. Male terminalia (Figure 51): Epandrium male epandrium in undissected specimens light brown, darker than remainder of abdomen, shiny; surstylus strong, distinct, long 

triangular, endowed only with a few weak setulae (Figure 

51); pre- and postgonite fused but distinct, pregonite (Figure 51) a rounded lobe with 4–5 moderately strong setae

along ventral margin, postgonite long, curved; distiphallus 

strongly black sclerotized, quite complex with several long 

narrow arms (Figure 51). Female terminalia: Seventh sternite quite large, fused to seventh tergite but with evident 

suture line; spermathecae very long and narrow; eighth sternite weak, oval with small strongly sclerotized lateral lobes 

each with cluster of setae on posterior margin; hypoproct 

with 2 short, strong setae; epiproct with 2 weak setae. 

Type Material. The holotype male is labeled 

“Daggett, Cal[ifornia] 14 IV 1955 W. R. M. Mason/

HOLOTYPE ♂ Trixoscelis gigapeza Foster & Mathis 

CNC [red].” The holotype is glued directly to the pin on 

its right side, is in excellent condition (abdomen removed 

and dissected; structures in an attached microvial), and is 

deposited in the CNC. Paratypes are as follows:

UNITED STATES. California. San Bernardino:

Daggett (34°51.8′N, 116°53.3′W), 13–14 Apr 1955, 

W. R. M. Mason (1♂, 1♀; CNC); Newberry Springs 

(34°49.6′N, 116°41.3′W), 14 Apr 1955, W. R. M. Mason 

(1♂; CNC); Phelan (11.2 km E; Baldy Mesa Road; 

34°25.6′N, 117°34.3′W; pan traps), 15–31 May 1982, 

J. T. Huber (3♂, 2♀; DEBU). San Diego: Borrego (N 

end Clark Lake; 33°20.3′N, 116°16.7′W), 23 Mar 1978, 

P. Adams, J. Slansky, M. S. Wasbauer (1♂, 2♀; CSCA).

Type Locality. United States. California. San 

Bernardino: Daggett (34°51.8′N, 116°53.3′W).

Distribution (Figure 52). Nearctic: 

United States (California).

Etymology. The species epithet, gigapeza, is 

of Latin derivation and refers to the large tarsal segments 

or “feet” of this species.

Remarks. Externally, this species closely resembles T. granditarsa, but structures of the male terminalia exhibit strong differences in the surstylus, gonites, 

and distiphallus.

Trixoscelis granditarsa (Foster and Mathis), 

new combination

FIGURES 53–56, 59–60

Pelomyia granditarsa Foster and Mathis, 2003:14.

Diagnosis. Body gray microtomentose; 2 or 4 

rows of scattered acrostichal setae; wing hyaline; lateral 

surface of basal flagellomere brown, medial surface yellow 

basally, brown distally, scape and pedicel yellow; vertex 

brown laterad of ocellar triangle; gena high, gena-to-eye 

ratio 0.45–0.50; male epandrium in undissected specimens 

large, yellowish.

Description. Body length 2.88–3.40 mm; 

uniformly gray microtomentose.

Head (Figures 59, 60): Eye as high as wide; ocellar triangle gray microtomentose; frons bare, yellow, 

parafrons whitish microtomentose; 2 strong, reclinate 

parafrontal setae; ocellar setae 1 strong pair, positioned at 

level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate 

FIGURE 51. Structures of male terminalia of Trixoscelis gigapeza 

Foster and Mathis: epandrium, surstylus, gonites, and aedeagus, lateral aspect. Scale = 0.1 mm.
number 637 • 3 7

postocellar seta; medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and 

divergent;occiput mostly gray microtomentose ventral 1/5 

concolorous with gena, with 1–2 rows of short dorsoclinate 

setulae dorsally, one row of several setae ventrally; antenna 

with basal flagellomere brown laterally, medially yellow 

on proximal half, brown on distal half, scape and pedicel 

yellow; arista brown, with sparse hairs. Gena-to-eye ratio 

0.45–0.50, white microtomentose, bearing several short,

scarcely discernible setulae ventrally and 2–3 slightly stronger setae posteriorly in addition to a pair of strong convergent oral vibrissae, extreme ventral margin shiny, chitinous; 

face white, convex; palpus yellow, labellum as long as head, 

straight, clypeus indistinct.

Thorax: Mesonotum uniformly gray microtomentose, sparsely setulose. Dorsocentral setae 5(2+3); acrostichal setae in 2–4 irregular rows; apical scutellar setae 

twice length of scutellum. Anepisternum mostly bare except 

for one strong seta on posterodorsal corner along with 3–4 

much smaller setulae in a cluster with the larger seta; katepisternum with 2 longer setae and one shorter one between 

them in a row along the posterodorsal edge. Wing hyaline. 

Halter white. Coxae, femora, and tibiae yellow, fore femur 

may be slightly darker, tarsi brown, male first and second 

tarsal segments swollen, hind ones greatly so; fore femur 

with a row of longer setae along posterodorsal and posteroventral surfaces; otherwise, legs evenly setulose except for 

preapical tibial setae on all tibiae.

FIGURE 52. Distribution map for Trixoscelis gigapeza Foster and Mathis.
3 8 • smithsonian contributions to zoology

Abdomen: Uniformly gray microtomentose, 

evenly setose. Male terminalia (Figures 53–55): Epandrium yellow in undissected specimens, oblong; surstylus strong, distinct, subtriangular, endowed only with a 

few weak setulae (Figure 53); pre- and postgonite fused, 

pregonite (Figure 54) a simple lobe with 4–5 setae along 

ventral margin, postgonite curved, subtriangular; distiphallus strongly black sclerotized, quite complex with 

many short lobes (Figure 55). Female terminalia: Seventh 

sternite and tergite strongly fused; spermathecae elongate, 

4× longer than wide; eighth sternite reduced to two distinct setaceous lobes; hypoproct with many weak setae; 

epiproct with two weak setae.

Type Material. The holotype male is labeled 

“B-15 1932/Las Vegas, Nev Apr 15, 1932 E. W. Davis/

Lepidium fremonti [Brassicaceae]/2017A/HOLOTYPE 

Pelomyia granditarsa ♂ Foster & W. N. Mathis USNM[red 

label; species name and ‘♂ Foster &’ handwritten].” The 

holotype is double mounted (glued to a paper triangle), 

is in poor condition (mostly greasy and partially covered 

with mounting glue), and is deposited in the USNM.

Other Specimens Examined. UNITED 

STATES. California. Riverside: Banning (33°55.5′N, 

116°52.6′W), 7 Apr 1931, A. C. Browne (1♀; CSCA). San 

Bernardino: Poison Canyon (35°39.3′N, 117°27.5′W), 

10 Apr 2003, W. N. Mathis, T. Zatwarnicki (6♂, 3♀; 

FIGURES 53–55. Structures of male terminalia of Trixoscelis granditarsa (Foster and Mathis) (California. San Bernardino: Poison Canyon): (53) epandrium, surstylus, and gonites, lateral aspect; (54) gonites, lateral aspect; (55) 

aedeagus, lateral aspect. Scale = 0.1 mm.
number 637 • 3 9

USNM); Apple Valley (34°30′N, 116°32.2′W), 10 May 

1955, W. R. Richards (1♀;CNC). San Diego: Borrego 

(north end Clark Lake; 33°20.3′N, 116°16.7′W; Malaise 

trap), 23 Mar 1978, P. Adams, J. Slansky, M. S. Wasbauer 

(1♂, 2♀; CSCA).

Type Locality. United States. Nevada. Clark: 

Las Vegas (36°10.5′N, 115°08.2′W).

Distribution (Figure 56). Nearctic: 

United States (California, Nevada).

Remarks. This species so closely resembles the 

genus Pelomyia of the family Tethinidae, even to the extent 

of having a shiny chitinous stripe along the ventral margin of the gena, that it was originally placed in that genus 

based on a single specimen (Foster and Mathis, 2003). 

This species and T. gigapeza also bear a resemblance to 

Stuckenbergiella, as illustrated by Cogan (1971), but do 

not exactly fit the description. The collection of many 

specimens on a recent trip to California has allowed us 

to thoroughly examine this enigmatic species, and we can 

now correctly place it in Trixoscelis.

Trixoscelis nevadensis Foster and Mathis, 

new species

FIGURES 63–65

Diagnosis. Body gray microtomentose; 2 

rows of acrostichal setae, proepimeral seta present; wing 

hyaline; antenna nearly completely yellow except for small 

area in center of lateral surface of basal flagellomere; 

FIGURE 56. Distribution map for Trixoscelis granditarsa (Foster and Mathis).
4 0 • smithsonian contributions to zoology

FIGURES 57–62. Photographs of heads: (57) T. fumipennis, anterior aspect; (58) same, lateral aspect; (59) T. granditarsa, anterior aspect; (60) 

same, lateral aspect; (61) T. ornata, anterior aspect; (62) same, lateral aspect.
number 637 • 4 1

vertex brown microtomentose; gena short, gena-to-eye 

ratio only 0.15; abdomen gray.

Description. Body length approximately 

1.70–2.50 mm (measurement taken after dissection).

Head: Eye round; ocellar triangle light gray

to brown microtomentose; frons bare, yellow, becoming darker dorsally, parafrons silvery microtomentose; 2 

strong, reclinate parafrontal setae; ocellar setae 1 strong 

pair, positioned at level of or anterior to anterior ocellus, 1 

additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong and divergent;occiput narrow, gray microtomentose 

dorsally becoming concolorous with gena ventrally, with 

1–2 rows of short dorsoclinate setulae; antenna nearly completely yellow except for small area in center of lateral surface of basal flagellomere, arista brown, with sparse hairs. 

Gena short, 0.15 eye height, white microtomentose, bearing 

1 row of 6–8 short ventroclinate setae along ventral edge in 

addition to a pair of strong convergent oral vibrissae; face 

white; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum gray microtomentose, vague

vittae along dorsocentral setae. Dorsocentral setae 5(2+3); 

acrostichal setae in 2 irregular rows; apical scutellar setae 

only twice length of scutellum. Mesonotum sparsely covered with minute setae. Anepisternum mostly bare except 

for one strong seta on posterodorsal corner along with 3–4 

much smaller setulae in a cluster; katepisternum with 2 

longer setae and several very short setulae along the posterodorsal edge. Wing hyaline. Halter white. Fore and hind 

femora light gray, all coxae, mid femur, tibiae and basal 

four tarsal segments yellow, 5th tarsal segment darker; fore 

femur with a row of longer setae along posterodorsal and 

posteroventral surfaces.

Abdomen: Uniformly gray microtomentose. Male

terminalia (Figures 64, 65): Surstylus (Figure 64) short robust, narrowing distally, slightly curved anteriorly in lateral 

view, somewhat long triangular in posterior view; pre- and 

postgonite fused but distinct (Figure 65), postgonite remnant bearing long, thin, curved lobe armed with strong, 

short spicule distally, ventral lobe rather large, bare except 

for a few sparse setulae on medial surface; aedeagus short, 

thin, weak, with complex sclerotization. Female terminalia: 

Seventh sternite and tergite strongly fused; spermathecae 

spherical; eighth sternite with two distinct setaceous lobes 

each bearing 2 strong setae; hypoproct with 2 short, strong 

setae; epiproct with two weak setae.

Type Material. The holotype male is labeled 

“USA.N[E]V[ADA]. Clark: Red Rock Canyon 36°08.7 

‘N, 115°25′W 11 May 2001 D. & W. N. Mathis/HOLOTYPE ♂ Trixoscelis nevadensis Foster & Mathis USNM 

[red]/USNM ENT 00118086 [plastic bar code label].” 

The holotype is double mounted (pinned from right side 

with a minuten mounted in a white silicone block), is in 

excellent condition (abdomen removed and dissected; 

structures in an attached microvial), and is deposited in 

the USNM. Paratypes are as follows:

UNITED STATES. California. Imperial: Holtville (3.2 

km E; 32°48.7′N, 115°22′W), 24 Apr 1973, P. W. Oman 

(1♂, 1♀; DEBU). Riverside: Morongo Valley (33°57.6′N, 

116°31.5′W; 915 m), 19 Apr 1955, W. R. M. Mason (1♂; 

CNC); Palm Springs (33°49.8′N, 116°32.7′W) 23 Apr 

1944, A. L. Melander (1♂; USNM. This specimen was 

among the paratype series of T. suffusa).

Nevada. Clark: Red Rock Canyon (36°08.7 ‘N, 

115°25′W), 11 May 2001, D. Mathis and W. N. Mathis 

(1♀; USNM).

Type Locality. United States. Nevada. Clark: 

Red Rock Canyon (36°08.7 ‘N, 115°25′W).

Distribution (Figure 63). Nearctic: 

United States (California, Nevada,).

Etymology. The species epithet, nevadensis, 

is of Latin derivation and refers to the type locality in 

Nevada.

Remarks. This species is very similar to T. 

deserta but shows distinct differences in structures of the 

male terminalia, particularly the gonites. The surstylus 

also lacks the strong seta on the anterior face.

Trixoscelis nigripeza Foster and Mathis, 

new species

FIGURES 63, 66–68

Diagnosis. Mesonotum gray, brown vittae along the dorsocentral and acrostichal rows of setae, 

4 scattered rows of acrostichal setae, proepimeral seta 

present, wing hyaline; antenna yellow except dorsal portion of outer surface of basal flagellomere brown; vertex 

black microtomentose; gena short, gena-to-eye ratio only 

0.17–0.22; abdomen gray; male epandrium in undissected 

specimens somewhat bulbous, light gray in contrast to the 

darker gray abdomen.

Description. Body length approximately 

2.00 mm (measurement taken after dissection).

Head: Eye round; ocellar triangle gray microtomentose; frons bare, yellow anteriorly, rather black 

posteriorly, parafrons white microtomentose; 2 strong, 

reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 
4 2 • smithsonian contributions to zoology

widely separated and convergent; lateral vertical seta long, 

strong and divergent;occiput widens posteriorly, gray microtomentose dorsally becoming concolorous with gena 

ventrally, with 1–2 rows of short dorsoclinate setulae; 

antenna yellow except dorsal portion of outer surface of 

basal flagellomere brown; arista brown, with sparse hairs. 

Gena short, gena-to-eye ratio 0.17–0.22, white microtomentose, bearing 1 row of 4–5 short ventroclinate setae 

along ventral edge in addition to a pair of strong convergent oral vibrissae; face white; palpus yellow, clypeus 

small indistinct.

Thorax: Mesonotum gray, brown vittae along the 

dorsocentral and acrostichal rows of setae. Dorsocentral 

setae 5(2+3); acrostichal setae in 4 irregular rows; apical 

scutellar setae only twice length of scutellum. Mesonotum 

sparsely covered with minute setae. Anepisternum mostly 

gray, brownish dorsally, mostly bare except for one strong 

seta on posterodorsal corner along with 3–4 much smaller 

setulae in a cluster; katepisternum with 2 longer setae and 

several very short setulae along the posterodorsal edge. 

Wing hyaline. Halter white. Coxae gray dorsally, yellow 

ventrally, fore and hind femora gray, tibia yellow, male 

mid and hind basistarsomere black and clearly swollen; 

fore femur with a row of longer setae along posterodorsal 

and posteroventral surfaces.

Abdomen: Uniformly gray microtomentose except

epandrium yellow, evenly setose. Male terminalia (Figures 

66–68): Epandrium in undissected specimens light gray, distinctly in contrast to the uniformly darker gray abdomen; 

surstylus (Figure 66 ) widely triangular, anteriorly curving 

FIGURE 63. Distribution map for Trixoscelis lagunaensis Foster and Mathis (dots), T. nigripeza Foster and Mathis (triangle), and T. nevadensis 

Foster and Mathis (squares).
number 637 • 4 3

in lateral view, robust triangular in posterior view; pre- and 

postgonite fused, complex (Figure 68) with postgonite remnant bearing sharp spicule distally, pregonite portion rather 

amorphous with a patch of setulae on the posterior margin; 

distiphallus (Figure 67) complex, strongly sclerotized, with 

two short strands distally. Female terminalia: Unknown.

Type Material. The holotype male is labeled 

“MEX[ICO]: B[aja]. Calif[ornia]. Sur Rancho Tablon 

area, 13 km. S[outh]. Guillermo Prieto/14/17 April 1983 

M. Wasbauer coll[ector]. malaise trap/HOLOTYPE ♂

Trixoscelis nigripeza Foster & Mathis CSCA [red].” The 

holotype is double mounted (glued to a cardboard triangle 

on its right side), is in fair condition (right basal flagellomere missing, left eye with small blob of dirt embedded 

dorsally, left wing slightly damaged, left leg missing tarsal 

segments 2–5; abdomen removed and dissected; structures 

in an attached microvial), and is deposited in the CSCA. 

Paratypes are as follows.

MEXICO. Baja California Sur. Rancho Tablon, Guillermo Prieto (21 km SW; 27°50′N, 113°19′W; Malaise 

trap), 14–17 Apr 1983, M. S. Wasbauer (1♂; CSCA).

Type Locality. Mexico. Baja California Sur. 

Rancho Tablon, Guillermo Prieto (21 km SW; 27°50′N, 

113°19′W; Malaise trap).

Distribution (Figure 63). Nearctic: 

Mexico (Baja California Sur).

Etymology. The species epithet, nigripeza, is 

of Latin derivation and refers to the black mid and hind 

basitarsi of the male.

Remarks. The female is unknown to date; 

however, the male mid and hind basitarsi are black and 

distinctly swollen, making this species quite distinct from 

its congeners.

Trixoscelis ornata (Johnson), new combination

FIGURES 41, 61–62, 69–70

Heterochroa ornata Johnson, 1895:306.

Peratochaetus ornatus. —Czerny, 1903:97 [generic combination]. —Aldrich, 

1905:571 [Nearctic catalog].

Spilochroa ornata—. Williston, 1908:297–298 [generic combination, key, 

figures of head, wing]. —Melander, 1913b:288 [diagnosis]; 1952:40 

[key, diagnosis]. —Wheeler, 1955:111 [key]. —Vockeroth, 1965:817 

[Nearctic catalog]. —Gill, 1968:7 [Neotropical catalog]. —Cole, 

1969:433 [distribution, diagnosis].

Diastata (Spilochroa) ornata. Malloch, 1931:30 [generic combination].

Diagnosis. Body yellowish brown, thorax 

may be yellow-brown to gray microtomentose, often 

with brown spots at bases of all setae including scutellar 

setae; 4 rows of acrostichal setae; wing heavily infuscated, 

FIGURES 64–65. Structures of male terminalia of Trixoscelis nevadensis Foster and Mathis (Nevada. Clark: 

Red Rock Canyon): (64) epandrium, surstylus, distiphallus, and hypandrium, lateral aspect; (65) gonites, lateral 

aspect. Scale = 0.1 mm.
4 4 • smithsonian contributions to zoology

with hyaline spots, costal cell with a central spot; antenna 

mostly yellow to mostly brown; vertex brown; gena very 

short, gena-to-eye ratio only 0.10; male epandrium in undissected specimens concolorous with abdomen.

Description. Body length 2.12–2.86 mm.

Head (Figures 61, 62): Eye higher than wide; 

ocellar triangle light gray microtomentose; frons bare, 

yellowish orange becoming darker dorsally, parafrons 

whitish-silver microtomentose; 2 strong, reclinate 

parafrontal setae; ocellar setae 1 strong pair, positioned 

at level of or anterior to anterior ocellus, 1 additional 

posterior pair of shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely 

separated and convergent; lateral vertical seta long, strong 

and divergent; occiput very narrow, gray dorsally, becoming white ventrally, microtomentose with 1 row of short 

dorsoclinate setulae; antenna mostly yellow to mostly 

brown; arista brown, with sparse hairs. Gena very short, 

gena-to-eye ratio 0.10, mostly white but with brown spot 

at base of oral vibrissa and faint brown along ventral row 

of setae, microtomentose, bearing 1 row of short ventroclinate setae along ventral edge in addition to a pair of 

FIGURES 66–68. Structures of male terminalia of Trixoscelis nigripeza Foster and Mathis (Mexico. 

Baja California Sur: Rancho Tablon): (66) surstylus, posterior aspect; (67) distiphallus, lateral aspect; (68) epandrium, surstylus, hypandrium, and gonites, lateral aspect. Scale = 0.1 mm.
number 637 • 4 5

stronger convergent oral vibrissae; face white; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum nonuniformly varying from

light yellowish brown to gray microtomentose often with 

brown spots at bases of all setae including scutellar setae, 

scutellum often marked with brown areas as well, sparsely 

covered with setae much shorter than the dorsocentral setae. 

Dorsocentral setae 5(2+3); acrostichal setae in 4 somewhat 

irregular rows; apical scutellar setae about twice length of 

scutellum. Pleural sclerites slightly darker than mesonotum, 

anepisternum mostly bare except for one strong seta on posterodorsal corner along with 3–4 much smaller setulae in a 

cluster; katepisternum with 2 longer setae and several very 

short setulae along the posterodorsal edge. Wing (Figure 

41) heavily infuscated, with round to oblong hyaline spots, 

one semicircular hyaline spot at wing tip between veins R4+5

and M, costal cell with a central spot. Halter white. Legs 

entirely yellow except fore femur may be darker brown, 

slightly swollen; fore femur with a row of longer setae along 

posterodorsal and posteroventral surfaces.

Abdomen: Gray microtomentose with brown

spots. Uniformly and evenly setose. Male terminalia (Figure 

69): epandrium brown, concolorous with abdomen, with 

a notch along the ventral edge (Figure 69); surstylus long 

triangular evenly endowed with setae; pre- and postgonites 

fused into one complex structure with postgonite remnant

bearing one weak terminal seta pregonite portion with 

one very strong seta and several weaker ones; distiphallus 

complex with longest lobe blunt (not figured, identical to 

T. polita [Figure 72]). Female terminalia: Seventh sternite 

with row of strong setae along the posterior margin, seventh sternite and tergite fused but with distinct suture line; 

spermathecae spherical, ducts not sclerotized; eighth sternite lightly sclerotized medially with distinct lateral lobes 

bearing 2 strong setae each; hypoproct with 2 short, strong 

setae; epiproct with weak setae.

Type Material. Johnson described T. ornata

from one male specimen, which he incorrectly identified 

as female. The holotype is labeled “Drayton Isl. Fl[orid]

a [29°22.14′N, 81°38.85′W] 5.9.94 [date handwritten, 

FIGURES 69. Structures of male terminalia of Trixoscelis ornata (Johnson) (Dominican Republic. 

LaVega: near Jarabacoa, Salto Baiguate (19°05.7’N, 70°37’W; 570 m)): epandrium, surstylus, hypandrium, and gonites, lateral aspect. Scale = 0.1 mm.
4 6 • smithsonian contributions to zoology

white label]/ HOLOTYPE No. [red label with no number]/ Type 7854 [number is handwritten on a red label]/ 

C. W. Johnson Collection [white].” The holotype is male, 

is in good condition, and is deposited in the MCZ.

Other Specimens Examined. Nearctic: 

UNITED STATES. Arizona. Cochise: Portal, Southwestern Research Station (8 km SW of Portal; 31°52.9′N, 

109°12.2′W; 1631 m), 8–18 Aug 1978, S. Wasbauer (1♂, 

1♀; CSCA). Maricopa: Avondale (32°26.1′N, 112°21′W), 

27 Dec 1960, Darden (1♂; USNM).

Florida. Alachua: Gainesville (29°39.1′N, 82°19.5′W), 

22 Mar–15 Apr 1956, G. B. Merrill, R. A. Morse (1♂, 

1♀; USNM). Collier: Seminole State Park (25°58.6′N, 

81°36.2′W), 17 May 1973, W. W. Wirth (1♂; USNM). 

Indian River: Vero Beach (27°38.3′N, 80°23.8′W), 18 

Feb 1914, G. G. Ainslee (1♂; USNM). Lee: Sanibel Island 

(26°26.4′N, 82°06.8′W; Malaise trap), 11 May 1973, 

W. W. Wirth (5♂, 4♀; USNM). Marion: Ocala (29°11.2′N, 

82°08.4′W), 18–22 Feb 1918 (2♀; USNM). Miami-Dade:

Biscayne Bay (25°30′N, 80°25′W), A. Slosson (1♂, 1♀; 

USNM); Coconut Grove (25°42.8′N, 80°15.4′W), 15 May 

1916 (1♀; USNM); Hialeah (25°51.5′N, 80°16.7′W), 14 

Jul 1965, C. Stegmaier (5♂, 3♀; USNM). Orange: Orlando (28°24.9′N, 81°17.9′W), 7 Feb 1918, G. G. Ainslie (1♂, 1♀; USNM). Volusia: (29°10.1′N, 81°31.3′W), 

5 Aug 1956, H. A. Denmark (1♀; USNM).

Georgia. Chatham: Savannah (32°05′N, 81°06′W; 

privy trap), 8 Oct 1954, J. W. Kilpatrick (1♀; USNM).

Texas. Bexar: San Antonio (29°25.5′N, 98°29.6′W), 

14 Dec 1957, D. H. Bixby (1♀; USNM). Cameron:

Brownsville (25°54.1′N, 97°29.8′W), 30 Apr–1 Sep 

1954, Townsend (2♀; USNM); Brownsville, Los Borregos 

(25°52.4′N, 97°26.8′W), 24 May 1904, H. S. Barber 

(1♀; USNM). Kerr: Kerrville (30°02.8′N, 99°08.4′W), 16 

Jun–22 Sep 1953, L. J. Bottimer (2♂; 6♀; USNM). Terrell: Dryden (30°02.7′N, 102°06.9′W), Apr–May 1954, 

O. Schomberg (1♂; USNM). Travis: Austin (30°18.1′N, 

97°45.7′W), 16–25 Oct 1950, 1952, M. R. Wheeler (2♂; 

USNM).

Neotropical: BAHAMAS. New Providence Island:

(24°57′N, 77°23.7′W), 19 May 1960, C. D. Babb (1♀; 

USNM).

MEXICO. Oaxaca: Mitla (16°55.6′N, 96°20.9′W), 

10 Aug 1962 (2♀; USNM). Sonora: Alamos (29°13′N, 

110°08′W), 24 Feb 1963, P. H. Arnaud, Jr. (1♀; USNM). 

Veracruz: Ocotal Chico (18°20′N, 94°48′W), 4–5 May 

1985, W. N. Mathis (1♀; USNM).

West Indies: DOMINICAN REPUBLIC. LaVega: near 

Jarabacoa, Salto Baiguate (19°05.7′N, 70°37′W; 570 m), 

16 May 1998, W. N. Mathis (1♂, 3♀; USNM). Pedernales:

Pedernales (18°01.8′N, 71°44.7′W; 570 m), 19–20 Mar 

1999, W. N. Mathis (3♂; USNM). Peravia: San Jose de 

Ocoa (9 km S; 18°31′N, 70°30.1′W; human dung), 19 Jul 

1987, A. L. Norrbom (4♀; USNM).

JAMAICA. St. Andrew: Cross Roads (18°15′N, 

77°30′W), 5 Oct 1954, T. H. Farr (1♂, 1♀; USNM); Kingston (17°58′N, 76°48′W), 27 Aug 1903, M. Grabham (2♀; 

USNM). St. Ann: Runaway Bay (18°28′N, 77°20′W; Malaise trap), 1–8 Mar 1970, W. W. Wirth (1♀; USNM).

PUERTO RICO. Mayagüez: Mona Island (18°05.2′N, 

67°53.4′W), Jul 1955, W. F. Pippin (1♂, 2♀; USNM). 

Yauco: Guanica Insular Forest (17°58.1′N, 66°51.7′W), 

6 Jul 1953, J. A. Ramos, J. Maldonado (1♂; USNM).

Distribution (Figure 70). Nearctic: 

United States (Arizona, Florida, Georgia, New Mexico, 

Texas). Neotropical: Bahamas, Mexico (Oaxaca, Sonora), 

West Indies (Dominican Republic, Jamaica, Mona Island, 

Puerto Rico).

Remarks. This species exhibits a rather spotted thorax and abdomen and differs from T. polita in having the abdomen gray to brown microtomentose, while 

T. polita shows a shiny, dark brown abdomen. Structures 

of the male terminalia are similar, demonstrating a close 

relationship, but an obvious difference is the notch along 

the ventral edge of the epandrium in T. ornata. Trixoscelis 

ornata and T. polita have a central brown spot in the costal cell, easily differentiating them from T. albibasis and 

T. punctipennis. All four species were previously placed in 

the genus Spilochroa.

Trixoscelis polita (Malloch), new combination

FIGURES 71–74, 88

Diastata (Spilochroa) polita Malloch, 1931:30.

Spilochroa polita. —Wheeler, 1955:111 [key, generic combination]. —Vockeroth, 1965:817 [Nearctic catalog]. —Cole, 1969:433 [distribution, 

diagnosis].

Spilochroa geminata Sabrosky, 1961:233. —Vockeroth, 1965:817 [Nearctic 

catalog]. —Gill, 1968:7 [Neotropical catalog]. NEW SYNONYM

Diagnosis. Body yellowish brown, thorax 

may be yellow-brown to gray microtomentose, abdomen 

polished dark brown; 4 rows of acrostichal setae; wing 

heavily infuscated, with hyaline spots, costal cell with a 

central spot; antenna mostly yellow to mostly brown; vertex brown; gena very short, gena-to-eye ratio only 0.10; 

male epandrium in undissected specimens concolorous 

with abdomen.

Description. Body length 2.12–2.86 mm.
number 637 • 4 7

Head: Eye higher than wide; ocellar triangle light 

gray microtomentose; frons bare, yellowish orange becoming darker dorsally, parafrons whitish-silver microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 1

strong pair, positioned at level of or anterior to anterior 

ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical 

seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent; occiput very narrow, 

gray dorsally, becoming white ventrally, microtomentose 

with 1 row of short dorsoclinate setulae; antenna mostly 

yellow to mostly brown; arista brown, with sparse hairs. 

Gena very short, gena-to-eye ratio 0.10, mostly white but 

with brown spot at base of oral vibrissa and faint brown

along ventral row of setae, microtomentose, bearing 1 row 

of short ventroclinate setae along ventral edge in addition 

to a pair of stronger convergent oral vibrissae; face white; 

palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum generally uniformly light yellowish brown to gray microtomentose, sparsely covered 

with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae in 4 somewhat irregular rows; apical scutellar setae about twice length of 

scutellum. Pleural sclerites slightly darker than mesonotum, 

anepisternum mostly bare except for one strong seta on posterodorsal corner along with 3–4 much smaller setulae in a 

cluster; katepisternum with 2 longer setae and several very 

short setulae along the posterodorsal edge. Wing (Figure 

88) heavily infuscated, with round to oblong hyaline spots, 

one semicircular hyaline spot at wing tip between veins R4+5

FIGURE 70. Distribution map for Trixoscelis ornata (Johnson).
4 8 • smithsonian contributions to zoology

and M, costal cell with a central spot. Halter white. Legs 

entirely yellow except fore femur may be darker brown, 

slightly swollen; fore femur with a row of longer setae along 

posterodorsal and posteroventral surfaces.

Abdomen: Highly polished dark brown; evenly setose. Male terminalia (Figures 71–73): epandrium brown, 

concolorous with abdomen; surstylus (Figure 71) long triangular evenly endowed with setae; pre- and postgonite fused 

into one complex structure (Figure 71) with postgonite remnant bearing one weak terminal seta pregonite portion with 

one very strong seta and several weaker ones; distiphallus 

complex with longest lobe blunt (Figure 72). Female terminalia: Seventh sternite with row of medium strength setae 

along the posterior margin, seventh sternite and tergite fused 

but with distinct suture; spermathecae spherical, ducts not 

sclerotized; eighth sternite ovoid with distinct lateral lobes 

bearing several strong setae each; hypoproct with 2 short, 

strong setae extremely close set appearing as one; epiproct 

very lightly sclerotized medially forming two subtriangles 

with 1 weak seta on the tip of each.

Type Material. Malloch based Diastrata 

polita on three female specimens. The holotype specimen is 

labeled “N[ew]. Mexico airplane P. Glick/ Type No. 43124 

U. S. N. M./Diastata (Spilochroa) polita Type [handwritten] Det. J. R. Malloch [printed] [white label with black 

border].” The holotype is double mounted (glued on right 

side on a paper triangle with still dried and unprocessed 

abdomen in an attached microvial), in good condition, 

FIGURES 71–73. Structures of male terminalia of Trixoscelis polita (Malloch) (Mexico. Baja California: Los Barriles): (71) epandrium, surstylus, hypandrium, gonites, and aedeagus, lateral aspect; (72) 

distiphallus, ventral aspect; (73) postgonite, ventroblique aspect. Scale = 0.1 mm.
number 637 • 4 9

and is deposited in the USNM. Paratypes are as follows: 

UNITED STATES. Texas. McLennan: Waco (31°33.6′N, 

97°11.3′W), no date given, G. W. Belfrage (1♀; USNM).

New Mexico. Dona Ana: Las Cruces (32°18.7′N, 

106°46.7′W), no date given, Townsend (1♀; USNM).

Sabrosky described Spilochroa geminata from 19 specimens (8♂, 11♀), including the holotype. The holotype male 

is labeled “Buckeye [33°22.2′N, 112°35′W] Ariz[zona]. 

Maricopa Co[unty] 1-18-61 Steiner-Wick Lu. fru. fly 

trap[white handwritten label]/HOLOTYPE Spilochroa 

geminata ♂ C. W. Sabrosky [red]/TypeNo. 65671 U.S.N.M. 

[red]/Spilochroa geminata SABR. Det. Sabrosky [white with 

black border].” The holotype is double mounted (glued on

right side on a paper triangle), is in good condition, and is 

deposited in the USNM. Paratypes are as follows: 

Nearctic: UNITED STATES. Arizona. Maricopa: 

Avondale (32°26.1′N, 112°21′W, trap), 6 Dec 1961 (1♂, 

2♀; USNM); Buckeye (33°22.2′N, 112°35′W, “Lu. Fru. Fly 

trap”), 11–18 Jan 1961, 9 Dec 1960, L. Darden, SteinerWick, A. N. Villa (2♂, 9♀; USNM); Cavecreek Post Office 

(4.8 km S; 33°31′N, 111°57′W), June 1952, H. K. Gloyd 

(1♂; USNM). Pima: Tucson (32°09.4′N, 110°52.6′W), 17 

Jun 1917, J. M. Aldrich (2♂; USNM).

MEXICO. Sonora: Imuris (30°47′N, 110°52′W), 16 

Apr 1952, R. E. Ryckman (1♂; USNM).

Type Locality. United States. New Mexico.

Other specimens examined. Nearctic: UNITED 

STATES. Arizona. Cochise: Douglas (45 km N; Highway 80; 31°40′N, 109°32.7′W), 12 Aug 1978, Freeberg, 

J. Slansky, M. S. Wasbauer (3♂; CSCA); Portal, Southwestern Research Station (8 km SW of Portal; 31°52.9′N, 

109°12.2′W; 1631 m), 8–18 Aug 1978, S. Wasbauer (7♂, 

2♀; CSCA).

Maricopa: Avondale (33°26.1′N, 112°21′W), 

6–27 Dec 1960, 1961, L. Darden (1♂, 1♀; USNM); 

Buckeye (33°22.2′N, 112°35′W), 6 Jan–10 Dec 1960, 

1961, L. Darden, A. N. Villa (4♀; USNM); Litchfield 

Park (33°29.6′N, 112°21.5′W), 6 Jan–15 Dec 1960, 

1961, L. Darden (2♀; USNM); Phoenix (33°26.9′N, 

112°04.5′W), 13 Dec 1960, E. O. Johnson (1♀; USNM). 

Santa Cruz: Nogales (31°20.4′N, 110°56′W), 14 Jun 

1963, J. T. Aguero (1♂; USNM).

California. Orange: Orange (33°48.3′N, 117°49.4′W; 

ex. California pepper), 17 Nov 1979, J. Harris (1♀; 

CSCA). Imperial: Ogilby Road, Chocolate Mountains (5 

km S junction with highway 78; 33°28′N, 115°35′W), 

20–22 Mar 1978, P. Adams, J. Slansky, M. S. Wasbauer 

(1♂, 4♀; CSCA).

Texas. Kerr: Kerrville (30°02.8′N, 99°08.4′W), 16 

Jun–22 Sep 1953, L. J. Bottimer (1♀; USNM). Uvalde:

Speir Ranch, Uvalde (5 km NW; 29°12.8′N, 99°47.5′W), 

2 May 1977, T. Eichlin, M. S. Wasbauer, (1♂; CSCA).

Neotropical: MEXICO. Baja California. El Pescadero, 

Playa Los Cerritos (23°19.8′N, 110°10.6′W), 14–17 Apr 

1979, M. S. Wasbauer (4♂, 15♀; CSCA);. Los Barriles 

(23°39′N, 109°42′W), 27–28 Apr, 5–6 May 1979, M. S. 

Wasbauer (26♂, 31♀; CSCA); Miraflores (6.5 km WSW; 

28°02′N, 113°14′W), 22–24 Apr 1979, M. S. Wasbauer 

(2♂, 11♀; CSCA); San Isidro (5.6 km WNW; 31°18′N, 

116°20′W; Canyon/Oasis), 22–23 Apr 1983, M. S. Wasbauer (1♀; CSCA); Sierra de la Laguna (27.8 air km ENE 

Todos Santos; 23°31.7′N, 110°02′W; 1830 m), 17–18 Dec 

1979 (1♀; CSCA). 

Baja California Sur. Rancho Tablon, Guillermo Prieto (21 km SW; 27°50′N, 113°19′W; Malaise trap), 14–18 

Apr 1983, M. S. Wasbauer (4♂, 15♀; CSCA). 

Sonora: Imuris (30°47′N, 110°52′W), 15 Apr 

1952, R. E. Ryckman (1♀; USNM); Bahia San Carlos (27°57.7′N, 111°01.5′W), 16 Feb–19 May 1984, 

1988, E. M. Fisher (4♂, 7♀; CSCA); Bahia San Carlos 

(27°57.7′N, 111°01.5′W), 3 Mar 1963, P. H. Arnaud, Jr. 

(5♀; USNM).

Distribution (Figure 74). Nearctic: 

United States (Arizona, California, New Mexico, Texas). 

Neotropical: Mexico (Sonora, Baja California, Baja California Sur).

Remarks. This species is easily distinguished 

from the closely related T. ornata by the shiny, dark brown 

abdomen and the rather uniformly gray thorax.

Trixoscelis punctipennis (Melander), 

new combination

FIGURES 75–76, 89

Spilochroa punctipennis Melander, 1913a:167; 1952:39 [diagnosis, key]. —

Wheeler, 1955:112 [key]. —Vockeroth, 1965:817 [Nearctic catalog]. 

—Cole, 1969:433 [distribution, diagnosis].

Diagnosis. Body light brown microtomentose, 

pleural sclerites darker brown somewhat shining, brown 

spots at bases of most setae including scutellar setae; 4 

rows of acrostichal setae; wing heavily infuscated, with 

hyaline spots, costal cell hyaline or completely darkened; 

antenna mostly yellow, center of basal flagellomere may 

be mostly brown; gena short, gena-to-eye ratio only 0.15.

Description. Body length approximately 

2.50–2.70 mm. 

Head: Eye higher than wide; ocellar triangle

light gray microtomentose; frons bare, yellowish orange 
5 0 • smithsonian contributions to zoology

becoming darker dorsally, parafrons whitish-silver microtomentose; 2 strong, reclinate parafrontal setae; ocellar 

setae 1 strong pair, positioned at level of or anterior to 

anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; 

lateral vertical seta long, strong and divergent;occiput 

very narrow, gray dorsally, becoming white ventrally, microtomentose with 1 row of short dorsoclinate setulae; 

antenna mostly yellow, center of basal flagellomere may 

be mostly brown; arista brown, with sparse hairs. Gena 

short, gena-to-eye ratio 0.15, mostly white but with diffuse brown spot at base of oral vibrissa, microtomentose,

bearing 1 row of short ventroclinate setae along ventral 

edge in addition to a pair of stronger convergent oral 

vibrissae; face white; palpus yellow, clypeus small indistinct, gray.

Thorax: Mesonotum usually uniformly light brown

microtomentose sometimes with a brown strip between 

dorsocentral setae extended to and including the scutellum, brown spots at bases of most setae. Dorsocentral setae 

5(2+3); acrostichal setae in 4 somewhat irregular rows; apical scutellar setae about twice length of scutellum. Pleural 

sclerites slightly to distinctly darker than mesonotum, anepisternum mostly bare except for one strong seta on posterodorsal corner along with 3–4 much smaller setulae in a 

cluster; katepisternum with 2 longer setae and several very 

short setulae along the posterodorsal edge. Wing (Figure 

89) heavily infuscated, with round to oblong hyaline spots, 

one semicircular hyaline spot at wing tip between veins R4+5

FIGURE 74. Distribution map for Trixoscelis polita (Malloch).
number 637 • 5 1

and M, costal cell hyaline. Halter white. Fore femur dark 

brown remainder of legs entirely light brownish yellow; 

fore femur with a row of longer setae along posterodorsal 

and posteroventral surfaces.

Abdomen: Uniformly gray microtomentose; evenly

setose. Male terminalia (Figure 75): Epandrium concolorous with remainder of abdomen; surstylus long triangular 

evenly endowed with setae; pre- and postgonites fused into 

one complex structure (Figure 75) with postgonite remnant 

bearing one weak terminal seta, pregonite portion with row 

of weak setae along ventral margin; distiphallus complex 

with longest lobe blunt distiphallus (not figured but see Figure 4) complex with four narrow lobes as in T. albibasis

(Figure 4). Female terminalia: Seventh sternite with wide 

notch on anterior margin and with row of medium strength 

setae along the posterior margin, seventh sternite and tergite fused but with distinct suture; spermathecae spherical, 

ducts not sclerotized; eighth sternite not evident but with 

distinct lateral lobes bearing several strong setae each; hypoproct with 2 short, strong setae extremely close set appearing nearly as one; epiproct with weak setae only.

Type Material. Melander described T. punctipennis from three specimens. The holotype is a male, one 

paratype is a female and the third specimen is missing. The 

holotype male is labeled “Pecos N[ew] M[exico]/July 26/ 

C[oc]k[ere]ll [ handwritten]/Type No. 18239 U.S.N.M. 

[red]/Spilochroa punctipennis Type Mel[ander] [white 

label with black border].” The holotype is pinned directly, 

is in good condition (verdigris on pin below specimen), 

and is deposited in the USNM. Paratype is as follows:

UNITED STATES. New Mexico. San Miguel: Las 

Vegas Hot Springs (35°39.2′N, 105°17.5′W), 11, 18 Aug, 

H. S. Barber (1♀; USNM).

Type Locality. United States. New Mexico. 

San Miguel: Pecos (35°34.5′N, 105°40.5′W).

Other Specimens Examined. Neotropical: MEXICO. Baja California Sur. El Pescadero, Playa 

Los Cerritos (23°19.8′N, 110°10.6′W), 14–17 Apr 1979, 

M. Wasbauer (5♂; 4♀; CSCA, USNM).

Distribution (Figure 76). Nearctic: 

United States (New Mexico). Neotropical: Mexico (Baja 

California Sur).

Remarks. Specimens of T. punctipennis are distinguished from other closely related species (T. ornata and

T. albibasis) by the generally uniformly gray coloration of 

the thorax and abdomen. We have only a few specimens 

of this apparently rare species, but several of them show 

a brown longitudinal band between the dorsocentral setae 

extended over the scutellum as well. This species seems 

most closely related to T. albibasis, based on slight but consistent differences in the form of the male postgonites. The 

distiphallus is apparently identical in both species.

Trixoscelis pygochroa Melander

FIGURES 77–82, 90

Trixoscelis pygochroa Melander, 1952: 49. —Vockeroth, 1965:818 [Nearctic catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Thorax light brown with silvery 

gray microtomentum, with slightly darker brown vittae 

along line of acrostichal setae, dorsocentral setae and 

supra-alar setae; 2 rather regular rows of acrostichal setae; 

wing infuscated anterior to vein R4+5, along both crossveins, and along vein CuA1

; antenna with scape grayish 

or yellowish, pedicel yellow, basal flagellomere yellow up 

to base of arista, remainder dark brown; gena moderately 

short, gena-to-eye ratio 0.25; abdomen gray microtomentose; male epandrium in undissected specimens bulbous, 

gray dorsally becoming yellowish.

Description. Body length 2.12–3.28 mm.

Head: Eye round, as high as wide; ocellar triangle 

light gray microtomentose; frons bare, light brown becoming dark brown laterad of ocellar triangle; parafrons silvery microtomentose; 2 strong, reclinate parafrontal setae; 

ocellar setae 1 pair, strong, additional 2–3 shorter ocellar 

setae; ocellar setae 1 strong pair, positioned at level of or 

anterior to anterior ocellus, additional 2–3 shorter, weaker 

ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; lateral 

vertical seta long, strong and divergent;occiput narrow, 

gray microtomentose with one row of short dorsoclinate 

setulae in addition to several scattered setae dorsally and 

ventrally; antenna with scape grayish or yellowish, pedicel 

FIGURE 75. Structures of male terminalia of Trixoscelis punctipennis (Melander) (Mexico. Baja California Sur: El Pescadero, Playa Los 

Cerritos): gonites, lateral aspect. Scale = 0.1 mm.
5 2 • smithsonian contributions to zoology

yellow, basal flagellomere yellow up to base of arista, remainder dark brown, arista dark brown with sparse hairs. 

Gena moderately short, gena-to-eye ratio 0.25, white microtomentose, a row of weak, small sometimes indistinct 

setulae along the ventral margin in addition to a pair of 

stronger convergent oral vibrissae; face white, palpus yellow, clypeus small indistinct, brown.

Thorax: Mesonotum light brown with silvery gray 

microtomentum, with slightly darker brown vittae along 

lines of acrostichal setae, dorsocentral setae and supraalar setae. Dorsocentral setae 5(2+3); acrostichal setae 

strong in 2 rather neat rows; apical scutellar setae only 

about twice length of scutellum. Anepisternum mostly 

bare except for one strong seta on posterodorsal corner 

along with only 3–4 much smaller setulae in a cluster; 

katepisternum with 2 longer setae and several very short 

setulae along the posterodorsal edge in addition to a row 

of short setulae just anterior to the midline of the sclerite. 

Wing (Figure 90) infuscated anterior to vein R4+5, along 

both crossveins, and along vein CuA1. Halter white. Legs 

entirely yellow or fore femur light gray, apical tarsomeres 

darker, fore femur with a row of longer setae along posterodorsal and posteroventral surfaces.

Abdomen: Uniformly grayish microtomentose, 

evenly setulose. Male terminalia (Figures 77–81): Epandrium (Figures 77, 78) in undissected specimens slightly 

enlarged, somewhat bulbous, gray dorsally becoming yellowish ventrally; surstylus (Figures 77, 78) long, narrow, 

strongly curved anteriorly in lateral view becoming black 

distally, curved inward in posterior view, endowed with 

many long, thin setae; pre- and postgonite fused, pregonite 

remnant a simple lobe with 2 or 3 setae (Figures 79, 80), 

FIGURE 76. Distribution map for Trixoscelis punctipennis (Melander).
number 637 • 5 3

postgonite portion a simple lobe with short, strong posteriorly directed seta; basiphallus dark, rectangular, distiphallus black, complex, with 4 strands of sclerotization 

(Figure 81). Female terminalia: Seventh sternite and tergite 

strongly fused; spermathecae conical; eighth sternite with 

rounded strongly sclerotized lobes bearing 3–4 strong 

setae; hypoproct with 2 short, strong setae in addition to 

several weak setulae; epiproct with 2 weak setae.

Type Material. Melander based T. pygochroa on a male and female specimen from Palm 

Springs, California, collected on different dates. We 

herein designate the male as lectotype. Both specimens 

are damaged. The male is missing the head, and the female is missing both wings. Our redescription is based on 

characters from both specimens. The lectotype specimen 

is labeled “PalmSpr[i]ngs CAL[IFORNIA] 24/4/44 A. L. 

Melander/HOLOTYPE Trixoscelis pygochroa Melander 

[red]/A. L. Melander Collection 1961 [white label with 

green stippling on right side]/Trixoscelis pygochroa Melander [white; handwritten]/LECTOTYPE ♂ Trixoscelis 

nitidiventris Melander Foster & Mathis USNM/USNM 

ENT 00118083 [plastic bar code label].” The lectotype 

FIGURES 77–81. Structures of male terminalia of Trixoscelis pygochroa Melander: (77) epandrium, cercus, surstylus, and gonites, lateral 

aspect; (78) epandrium and surstyli, posterior aspect; (79) gonites, lateral aspect; (80) same, ventroblique aspect; (81) aedeagus, lateral aspect. 

Scale = 0.1 mm.
5 4 • smithsonian contributions to zoology

is double mounted (pinned from ventral side with a minuten mounted in a cardboard square), is in good condition (missing the head; structures of the male terminalia 

in an attached microvial), and is deposited in the USNM. 

Paralectotypes are as follows:

UNITED STATES. California. Riverside: Palm Springs 

(33°49.8′N, 116°32.7′W), 10 Nov 1944, A. L. Melander 

(1♀; USNM).

Type Locality. United States. California. 

Riverside: Palm Springs (33°49.8′N, 116°32.7′W).

Other Specimens Examined. MEXICO. 

Baja California: El Crucero (25.7 km SE Laguna Chapala; 29°23′N, 114°22′W; 600 m), 13 Apr 1983, M. S. 

Wasbauer (2♀; CSCA). Rancho San Ignacio (26 km E Rosarito; 32°20.9′N, 117°02.5′W; Malaise trap), 26–27 Mar 

1982, J. Slansky, M. S. Wasbauer (2♂, 2♀; CSCA).

Baja California Sur. Arroyo San Gregorio (13 km 

WNW of La Purísima; 26°13.6′N, 112°21.8′W), 24–24 

Apr 1983, M. S. Wasbauer (1♂, 2♀; CSCA). Rancho 

Tablon, Guillermo Prieto (21 km SW; 27°50′N, 113°19′W; 

Malaise trap), 3–17 Apr 1982, 1983, M. S. Wasbauer (1♂, 

8♀; CSCA).

UNITED STATES. Arizona. Coconino: Tuba City 

(36°08.1′N, 111°14.4′W; 1430 m; desert grass, scrub) 

22–25 Jul 1979, S. Peck, J. Peck (1♂; DEBU).

California. Imperial: Westmoreland (31°01.9′N, 

115°37.4′W), 10 Apr 1917, J. M. Aldrich (2♂; USNM).

Inyo: Trona Golf Club (35°49.7′N, 117°19.8′W), 25–28 

Apr 2002, D. Mathis, W. N. Mathis (2♂, 4♀; USNM). San 

Diego: Anza-Borrego Desert State Park, Clark Dry Lake 

(33°13.7′N, 116°15.7′W), 31 Mar 1977, J. Slansky, M. S. 

Wasbauer (2♂, 4♀; CSCA); Borrego (N end Clark Lake; 

33°20.3′N, 116°16.7′W), 23 Mar 1978, P. Adams, J. Slansky, M. S. Wasbauer (32♂, 29♀; CSCA).

Utah. Emery: Wild Horse Creek (2.4 km NW Wild 

Horse Butte; 38°34.7′N, 110°43.2′W; 1495 m), 26–27 Jul 

1982, A. K. Menke, K. Menke (2♂; USNM).

Wyoming. Uinta: Lonetree (41°03.3′N, 110°09.3′W; 

2320 m; sagebrush, carrion), 1–9 Aug 1979, S. Peck, J. 

Peck (2♂; DEBU).

Distribution (Figure 82). Nearctic: Mexico (Baja California, Baja California Sur), United States 

(Arizona, California, Utah, Wyoming).

Remarks. Specimens of T. pygochroa and 

T. deserta can often be difficult to distinguish from each 

other, especially where the maculation pattern in the wing 

is reduced. The body coloration of the two species is virtually identical. Structures of the male terminalia are the 

only reliable characters to separate these two rather common species.

Trixoscelis suffusa Melander

FIGURES 83–87, 91–92

Trixoscelis suffusa Melander, 1952:50. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Thorax light brown to yellow 

microtomentose with indistinct lighter area along lateral 

edges of mesonotum becoming lighter yellow on ventral 

portion of anepisternum and katepisternum, 2 irregular 

rows of sometimes weak acrostichal setae; wing faintly 

darkened anterior to vein R2+3 only; antenna with scape 

and pedicel yellowish, basal flagellomere yellowish only 

along ventral margin, dorsal area brown to black; gena 

moderately short 0.28; abdomen gray, darker than thorax; male epandrium in undissected specimens somewhat 

enlarged, yellowish ventrally, gray dorsally.

Description. Body length 1.79–2.50 mm.

Head: Eye nearly round; ocellar triangle light gray

microtomentose; frons bare, orange becoming brown laterad of ocellar triangle; parafrons silvery microtomentose; 

2 strong, reclinate parafrontal setae; ocellar setae 1 strong 

pair, positioned at level of or anterior to anterior ocellus, 1 

additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong and divergent; occiput quite narrow, very light gray 

microtomentose with one row of short dorsoclinate setulae 

in addition to only a few evenly scattered setae dorsally and 

ventrally; antenna with scape and pedicel yellowish, basal 

flagellomere yellowish only along ventral margin, dorsal 

area brown to black, arista dark brown with sparse hairs. 

Gena moderately short, gena-to-eye ratio 0.28, white microtomentose, a row of setulae along the ventral margin in

addition to a pair of stronger convergent oral vibrissae; face 

white, palpus yellow, clypeus small indistinct, yellow.

Thorax: Thorax light brown to yellow microtomentose with indistinct lighter area along lateral edges of 

mesonotum becoming lighter yellow on ventral portion 

of anepisternum and katepisternum. Dorsocentral setae 

5(2+3); acrostichal setae weak in 2 irregular rows; apical 

scutellar setae only about twice length of scutellum. Anepisternum mostly bare except for one strong seta on posterodorsal corner along with only 3–4 much smaller setulae 

in a cluster; katepisternum with 2 longer setae and several 

very short setulae along the posterodorsal edge in addition 

to a row of short setulae just anterior to the midline of the 

sclerite. Wing (Figures 91, 92) only faintly darkened anterior to vein R2+3, otherwise clear. Halter white. Legs may be 
number 637 • 5 5

entirely yellow or fore femur may be slightly darker, apical tarsal segments darker, fore femur with a row of longer 

setae along posterodorsal and posteroventral surfaces.

Abdomen: Uniformly gray microtomentose, evenly

setulose. Male terminalia (Figures 83–86): Epandrium in 

undissected specimens slightly enlarged, somewhat bulbous, 

gray dorsally becoming yellowish ventrally; surstylus (Figures 83, 84) long, narrow, slightly curved anteriorly in lateral view, curved inward in posterior view, endowed with 

many long, thin setae; pre- and postgonite fused but distinct, 

postgonite remnant bearing short, terminal seta, (Figure

85); pregonite portion bilobed, the dorsal lobe with tuft of 

weak setulae, ventral lobe bare except for tuft of very weak 

setulae somewhat anteriorly; aedeagus black, complex, with 

two areas of sclerotization (Figure 86). Female terminalia: 

seventh sternite and tergite strongly fused; spermathecae 

spherical; eighth sternite reduced to two distinct setaceous 

lobes; hypoproct with two distinct setae in addition to several other weaker ones; epiproct with two weak setae.

Type Material. Melander described T. suffusa from 28 specimens collected in California and Washington. We have examined all 28, two of which were not 

published. Melander wrote that the “types” are from Oak 

Glen, California, with a collection date of 2 July 1945. 

There is only one such specimen in the series and it is 

a male. We herein designate this specimen as lectotype. 

The lectotype specimen is labeled “Oak Glen [34°03′N, 

116°56.9′W] CAL[IFORNIA. San Bernardino:] 2/7/45 

A. L. Melander/HOLOTYPE Trixoscelis suffusa Melander 

[red]/ A. L. Melander Collection 1961 [white label with 

FIGURE 82. Distribution map for Trixoscelis pygochroa Melander.
5 6 • smithsonian contributions to zoology

green stippling on right side]/Trixoscelis suffusa Melander 

[handwritten]/LECTOTYPE ♂ Trixoscelis suffusa Melander Foster & Mathis USNM/USNM ENT 00118082 

[plastic bar code label].” The lectotype is double mounted 

(pinned from ventral side with a minuten mounted in a 

cardboard square), is in good condition (structures of the 

male terminalia in an attached microvial; some mesonotal 

setae rubbed off, some setae of the head disoriented), and 

deposited in the USNM. Paralectotypes are as follows:

UNITED STATES. California. Riverside: Mount 

Home Canyon (33°32.4′N, 116°29′W), 13 May 1947, A. 

L. Melander (1♀; USNM); San Bernardino: Barton Flats 

(34°10.4′N, 116°51.8′W), 7 Sep 1946, A. L. Melander (1♀; 

USNM); Crestline (34°14.5′N, 117°17.1′W), 4 Jul 1942, 

A. L. Melander (1♂, 2♀; USNM); Falls Valley (34°05′N, 

116°54.8′W), 10 Jul 1940, A. L. Melander (1♀; USNM); 

Mountain Home (34°06′N, 117°W), 9 Jul–24 Aug 1944, 

1945 (3♂, 3♀; USNM); Scotland (34°14.5′N, 117°29.9′W), 

19 Sep 1943, A. L. Melander (5♀; USNM); 7-Oaks, 20 Jun 

1945, A. L. Melander (1♂; USNM; labeled as a paratype 

but not published as such); South Fork Santa Ana River 

(34°10.3′N, 116°49.8′W), 18 Jun 1945, A. L. Melander 

(1♀; USNM; labeled as a paratype but not published as such) 

Victorville (34°32.2′N, 117°17.5′W), 22 May 1945, A. L. 

Melander (1♂; USNM). San Diego: Oak Grove (33°23.1′N, 

116°47.4′W), 8 May 1945, A. L. Melander (2♀; USNM). 

San Luis Obispo: Morro Bay (35°20.1′N, 120°51.1′W), 27 

Jul 1940, A. L. Melander (1♀; USNM).

Washington. Chelan: Entiat (47°40.6′N, 120°12.5′W), 

26 Jul 1919, A. L. Melander (1♀; USNM). Klickitat: Goldendale (45°49.2′N, 120°49.3′W), 23 Jul 1921, A. L. Melander (3♀; USNM).

Type Locality. United States. California. San 

Bernardino: Oak Glen (34°03′N, 116°56.9′W).

Other Specimens Examined. UNITED 

STATES. Arizona. Mohave: Littlefield (36°53.1′N, 

113°55.8′W), 1 May 2002, D. Mathis, W. N. Mathis (1♀; 

USNM).

FIGURES 83–86. Structures of male terminalia of Trixoscelis suffusa Melander: (83) epandrium, surstylus, 

hypandrium, and distiphallus, lateral aspect; (84) epandrium and surstyli, posterior aspect; (85) gonites, lateral 

aspect; (86) distiphallus, lateral aspect. Scale = 0.1 mm.
number 637 • 5 7

California. Los Angeles: Lancaster (34°41.9′N, 

118°08.2′W), 5 Jul 1956, E. I. Schlinger (1♂; USNM). 

Monterey: Nacimiento (35°48.5′N, 120°44.5′W), 13–14 

Aug 1969, B. Hocking (2♀; CNC). Riverside: University 

of California, Riverside (33°58.5′N, 117°19.7′W, Malaise trap); 7–21 Jun 1983, D. Yu (2♂, 5♀; DEBU). San 

Bernardino: Mountain Home (34°06′N, 117°W), 29 Jun 

1949, 4 Aug 1953, A. L. Melander (1♂, 2♀; USNM); 

Twenty-nine Palms (34°08.1′N, 116°03.3′W), 6 Oct 1949, 

A. L. Melander (1♂; USNM).

Nevada. Clark: Red Rock Canyon (36°08.7′N, 

115°25′W), 11 May 2001, D. Mathis and W. N. Mathis 

(1♂, 1♀; USNM).

New Mexico. Catron: Gila National Forest, Whitewater Canyon (33°21.6′N, 108°04′W), 30 May 1991, J. E. 

Swann (1♂, 1♀; DEBU); Glenwood (33°19′N, 108°53′W), 

1 Jun 1972, W. W. Wirth (1♀; USNM). Grant: Gila National Forest, Lake Roberts (33°02′N, 108°10′W), 29 May 

1991, J. E. Swann (1♂, 1♀; DEBU).

Oregon. Umatilla: McNary, McNary Dam Wildlife 

Area (45°56.4′N, 119°17.9′W), 11 Aug 1993, R. S. Zack 

(1♂; WSU).

Washington. Grant: O’Sullivan Dam (46°59′N, 

119°17.5′W), 22 Jul 1954, M. T. James (5♂, 3♀; USNM, 

WSU). Whitman: Colton (16 km SW; Steptoe Canyon; 

46°27.1′N, 117°12.4′W), 3 Aug 1974, W. J. Turner (8♂, 

3♀; WSU).

Distribution (Figure 87). Nearctic: 

United States (Arizona, California, Nevada, New Mexico, 

Oregon, Washington).

FIGURE 87. Distribution map for Trixoscelis suffusa Melander.
5 8 • smithsonian contributions to zoology

FIGURES 88–95. Photographs of right wings, dorsal aspects: (88) Trixoscelis polita; (89) T. punctipennis; (90) T. pygochroa; (91) T. suffusa 

(dark); (92) T. suffusa (light); (93) T. signifera (light); (94) T. signifera (dark); (95) T. cinerea.
number 637 • 5 9

Remarks. This small, somewhat frail appearing species is very similar in appearance to T. deserta and T. pygochroa. It differs from them not only in structures of the 

male terminalia but in having the wing only vaguely darkened anterior to vein R2+3 and with no darkening on the 

crossveins. This character varies, however.

Trixoscelis triplex Melander

FIGURES 96–99

Trixoscelis triplex Melander, 1952:50. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Gill, 1968:7 [catalog, distribution]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Thorax light brown microtomentose with distinct vittae along the line of the dorsocentral and acrostichal setae and a lighter one extended 

from the anterior edge of the mesonotum to the anterior 

intra-alar seta, 2 rather straight rows of acrostichal setae; 

wing hyaline; antenna with scape and pedicel yellowish, 

basal flagellomere varies from light brown to black except 

area around base of arista yellow; gena moderately short, 

gena-to-eye ratio 0.20–0.25; abdomen gray, darker than 

thorax; male epandrium in undissected specimens slightly 

enlarged, concolorous with abdomen.

Description. Body length 1.72–2.93 mm.

Head: Eye nearly round; ocellar triangle light gray

microtomentose; frons bare, yellow becoming brown laterad of ocellar triangle; parafrons silvery microtomentose; 

2 strong, reclinate parafrontal setae; ocellar setae 1 strong 

pair, positioned at level of or anterior to anterior ocellus, 1 

additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong and divergent; occiput quite narrow, very light gray 

microtomentose with one row of short dorsoclinate setulae 

in addition to only a few scattered setae dorsally and ventrally; antenna with scape and pedicel yellow; in females, 

basal flagellomere mostly black, yellow only around base 

of arista, in males, basal flagellomere mostly yellow area 

around base of arista black, arista dark brown with sparse 

hairs. Gena moderately short, gena-to-eye ratio 0.20–0.25, 

white microtomentose, a row of setulae along the ventral

margin in addition to a pair of stronger convergent oral vibrissae; face white, palpus yellow, clypeus small indistinct, 

light brown.

Thorax: Thorax light brown microtomentose 

with distinct vittae along the line of the dorsocentral and 

acrostichal setae and a lighter one extended from the 

anterior edge of the mesonotum to the anterior intra-alar 

seta, abdomen gray, darker than thorax. Dorsocentral 

setae 5(2+3), 2 rather straight rows of acrostichal setae; 

apical scutellar setae only about twice length of scutellum. 

Anepisternum mostly bare except for one strong seta on 

posterodorsal corner along with only 3–4 much smaller 

setulae in a cluster; katepisternum with 2 longer setae and 

several very short setulae along the posterodorsal edge in 

addition to a row of short setulae just anterior to the midline of the sclerite. Wing hyaline. Halter white. Legs entirely yellow except fore femur and fore tarsus light gray, 

apical tarsomeres on remaining legs darker, fore femur 

with a row of longer setae along posterodorsal and posteroventral surfaces.

Abdomen: Uniformly grayish to brownish microtomentose, evenly setulose. Male terminalia (Figures 96–

98): Epandrium in undissected specimens slightly enlarged, 

may be concolorous with remainder of abdomen or somewhat yellowish; surstylus (Figures 96, 97) darkened distally, 

long, narrow, pointed, with row of 6–8 long, strong, posteroventrally directed setae along dorsal margin; pre- and

postgonite largely separated, pregonite complex (Figure 

98); postgonite with short, strong seta directed posteriorly; 

aedeagus black, complex (Figure 98). Female terminalia: 

Seventh sternite and tergite strongly fused; spermathecae 

spherical; eighth sternite darkly sclerotized, hemispherical 

with two distinct setaceous lobes each bearing 3–4 strong 

setae; hypoproct with two short, strong setae; epiproct with 

two weak setae.

Type Material. Melander described T. triplex from 14 specimens collected in California and 

Mexico. We have seen all original specimens. Melander 

stated that the “types” are from Organ Pipe Cactus National Monument in Arizona and were collected on 18 

April 1947. Because there are two such specimens both on 

the same pin and they are a male and a female we herein 

designate the male specimen as lectotype. The lectotype 

is labeled “Organpipe Mon[ument] ARIZ[ONA] 18/4/47 

A. L. Melander/HOLOTYPE Trixoscelis triplex Melander 

[red]/ALLOTYPE Trixoscelis triplex Melander [red]/A. L. 

Melander Collection 1961 [white label with green stippling on right side]/Trixoscelis triplex Melander [handwritten]/LECTOTYPE ♂ Trixoscelis triplex Melander 

Foster & Mathis USNM [red]/USNM ENT 00118081 

[plastic bar code label].” The lectotype is the top specimen 

of two and both are double mounted (pinned from ventral 

side with a minuten mounted in a cardboard square), is in 

excellent condition (structures of the male terminalia in 

an attached microvial), and are deposited in the USNM. 

Other paralectotypes are as follows: 
6 0 • smithsonian contributions to zoology

MEXICO. Sonora: Sonoyta (31°51.8′N, 112°51.4′W), 

21 Apr 1947, A. L. Melander (1♀; USNM).

UNITED STATES. Arizona. Mohave: Ligurta (Golden 

Valley; 35°21.9′N, 114°14.8′W), 9 Apr 1947, A. L. Melander (1♀; USNM). Pima: Sabino Canyon (31°52′N, 

111°27.4′W), 5 May 1942 (Melander, in error, wrote that 

this specimen is dated 5 June 1942), A. L. Melander (1♀; 

USNM); Organ Pipe National Monument (32°02.5′N, 

112°52.5′W), 15 Apr 1947, A. L. Melander (1♂; USNM).

California. Imperial: Gordon’s Well (33°08.9′N, 

115°19.5′W), 8 Apr 1947, A. L. Melander (1♀; USNM). 

Riverside: Palm Springs (33°49.8′N, 116°32.7′W), 23–24 

Apr 1944, A. L. Melander (1♂, 1♀; USNM). There was 

another male of this series but we have determined that it 

is actually T. nevadensis new species). San Diego: Borrego, 

Palm Canyon (33°13.2′N, 116°20.1′W), 2–4 May 1945, 

A. L. Melander (2♂, 2♀; USNM). 

Type Locality. United States. Arizona. 

Pima: Organ Pipe National Monument (32°02.5′N, 

112°52.5′W).

Other Specimens Examined. UNITED 

STATES. Arizona. Cochise: Portal, Southwestern Research 

Station (8 km SW of Portal; 31°52.9′N, 109°12.2′W; 

1631 m), 14 May 1976, G. A. Foster (1♂; USNM). Pima: 

Organpipe Cactus National Monument (32°02.5′N, 

112°52.5′W), 21 Apr 1979, K. N. Barber (1♂; DEBU).

California.Imperial: Glamis (32°59.9′N, 115°04.3′W), 

17 Apr 1969, R. R. Pinger (5♂, 3♀; USNM); Ogilby 

Road, Chocolate Mountains (5 km S junction with highway 78; 33°28′N, 115°35′W; Malaise trap), 20–22 Mar 

FIGURES 96–98. Structures of male terminalia of Trixoscelis triplex Melander (locality unknown): (96) epandrium, surstylus, 

hypandrium, and gonites, lateral aspect; (97) epandrium and surstyli, posterior aspect; (98) pregonite, postgonite, hypandrium, 

aedeagus, and aedeagal apodeme, lateral aspect. Scale = 0.1 mm.
number 637 • 6 1

1978, P. Adams, J. Slansky, M. S. Wasbauer (1♂; CSCA). 

Riverside: Desert Center (33°42.8′N, 115°24.1′W), 2 May 

1955, W. R. M. Mason (5♂, 11♀; CNC); Hunter’s Spring 

(33°29.3′N, 115°47.5′W), 10 May 1952 (1♀; USNM). 

San Diego: Borrego (N end Clark Lake; 33°20.3′N, 

116°16.7′W; Malaise Trap), 23 Mar 1978, P. Adams, 

J. Slansky, M. S. Wasbauer (3♂, 5♀; CSCA).

Distribution (Figure 99). Nearctic: Mexico (Sonora), United States (Arizona, California).

Remarks. This species has distinctive brown 

vittae on the mesonotum along the dorsocentral and 

acrostichal tracks and the anterior portion of the intra-alar 

seta. They are more distinct than the vittae found in other 

Trixoscelis species. Structures of the male terminalia are 

unusual in having a series of comparatively long, robust 

setae along the dorsal margin of the surstylus. These setae 

cannot usually be seen in undissected specimens, which 

typically have these structures curled inside the abdomen.

Trixoscelis tumida Melander

FIGURES 100–104, 116–117

Trixoscelis tumida Melander, 1952:51. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Mesonotum light brown microtomentose becoming somewhat orange laterally, entirely 

without brown vittae, dorsocentral setae with dark area 

around base, 4 irregular rows of acrostichal setae; wing 

FIGURE 99. Distribution map for Trixoscelis triplex Melander.
6 2 • smithsonian contributions to zoology

hyaline; antenna with scape and pedicel yellowish, basal 

flagellomere mostly brown to black except around base of 

arista; gena moderately high, gena-to-eye ratio 0.33; abdomen gray, darker than thorax; male epandrium in undissected specimens not enlarged, brownish to somewhat 

orange in contrast to the uniformly gray abdomen.

Description. Body length 2.19–3.22 mm.

Head (Figures 116, 117): Eye nearly round; ocellar triangle light gray microtomentose; frons bare, yellow becoming slightly darker laterad of ocellar triangle; 

parafrons silvery microtomentose; 2 strong, reclinate 

parafrontal setae; ocellar setae 1 strong pair, positioned at 

level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate 

postocellar seta; medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and 

divergent; occiput wide, gray microtomentose with one 

row of short dorsoclinate setulae in addition to only a few 

scattered setae dorsally and ventrally, occiput extends into 

gena under eye; antenna with scape and pedicel yellowish, 

basal flagellomere mostly brown to black except around 

base of arista, arista dark brown with sparse hairs. Gena 

moderately high, gena-to-eye ratio 0.33, white microtomentose, a row of setulae along the ventral margin in addition to a pair of stronger convergent oral vibrissae; face 

white, palpus yellow, clypeus small indistinct, light brown.

Thorax: Mesonotum light brown microtomentose becoming somewhat orange laterally, entirely without 

brown vittae, dorsocentral setae with dark area around 

base; abdomen gray, darker than thorax, abdomen gray, 

darker than thorax. Dorsocentral setae 5(2+3), 4 scattered rows of acrostichal setae; apical scutellar setae only 

about twice length of scutellum. Proepimeron with 1 seta. 

Anepisternum mostly bare except for one strong seta on 

posterodorsal corner along with only 3–4 much smaller 

setulae in a cluster; katepisternum with 2 longer setae and 

several very short setulae along the posterodorsal edge in 

addition to a row of short setulae just anterior to the midline of the sclerite. Wing hyaline. Halter white. Legs yellow 

except fore femur and fore and hind tarsi light brown, the 

basitarsus tending to be the darkest, male hind basitarsus 

distinctly swollen, fore basitarsus slightly so, fore femur 

with a row of longer setae along posterodorsal and posteroventral surfaces.

Abdomen: Uniformly gray microtomentose, evenly

setulose. Male terminalia (Figures 100–103): Epandrium in 

undissected specimens not enlarged, brownish to somewhat 

orange in contrast to uniformly gray abdomen; surstylus 

(Figures 100, 101) entirely devoid of setae, rather robust, 

rectangular at base becoming spatulate distally, spatulate 

area darker then rest of surstylus, pre- and postgonite fused 

but distinct, pregonite (Figure 102) narrow, endowed with 

long, strong seta directed posteriorly, postgonite reduced to 

narrow lobe with three or four short setae at tip; aedeagus 

black, complex (Figure 103). Female terminalia: seventh 

sternite and tergite strongly fused; spermathecae rather 

bulbous; eighth sternite with two distinct setaceous lobes; 

hypoproct with two short strong setae; epiproct with two 

weak setae.

Type Material. Melander described T. tumida

from 29 specimens collected in California, Washington, and Oregon. Melander designated the two specimens from Washington, a male and female, as “types.” 

Of the 12 male and 15 female “paratypes” he reported, 

only seven males and 13 females are in the USNM collection. We have found that three specimens (2♀ from 

Palm Springs and 1♂ from Corona del Mar) are clearly 

not conspecific with others of the type series. The Corona del Mar specimen is T. lagunaensis new species, 

the ♀ specimens are of uncertain identity. Therefore the 

existing actual paralectotype series of T. tumida consists 

of 17 specimens (plus the female “type” now becomes 

an additional paralectotype bringing the new total to 

18 paralectotypes). Melander wrote that the “types” are 

from Lucerne [48°12.1′N, 120°35.5′W; 338 m], on Lake 

Chelan, Washington, and were collected on 29 July 1919. 

We are designating the male as lectotype. The lectotype 

male is labeled “LakeChelan Lucerne W[ASHINGTO]N 

29 July [19]19/ A. L. Melander”/HOLOTYPE Trixoscelis tumida Melander [red]/ A. L. Melander Collection 

1961 [white label with green stippling on right side]/

LECTOTYPE ♂ Trixoscelis tumida Melander Foster & 

Mathis USNM [red]/USNM ENT 00118080 [plastic bar 

code label].” The specimen is double mounted (pinned 

from ventral side with a minuten mounted in a cardboard 

square), is in excellent condition, and is deposited in the 

USNM. Paralectotypes are as follows:

UNITED STATES. California. Amador: Silver Lake 

(38°31.3′N, 120°19.4′W), 1 Aug 1935, H. H. Kiefer (1♀; 

CSCA); Los Angeles: Big Pines (34°22.7′N, 117°41.4′W), 

2–9 Aug 1944, A. L. Melander (2♀; USNM); Mojave 

Desert, Lovejoy Springs (34°36.3′N, 117°49.8′W), 10 Sep 

1944, A. L. Melander (1♂; USNM). San Bernardino: Barton Flats (34°10.4′N, 116°51.8′W, 31 Aug–4 Sep 1944, 

A. L. Melander (3♂, 3♀; USNM); Crestline (34°14.5′N, 

117°17.1′W), 4 Jul 1942, A. L. Melander (2♀; USNM); 

Jenks Lake (34°09.9′N, 116°52.9′W), 20 Jun 1944, 

A. L. Melander (1♀; USNM); San Diego: Green Valley 

(32°54.4′N, 116°34.9′W), 26 Jul 1944, A. L. Melander 

(1♂, 3♀; USNM).
number 637 • 6 3

Oregon. Hood River: Mount Hood (45°22.4′N, 

121°41.7′W; 915 m), 29 Jul 1921, A. L. Melander (1♂; 

USNM).

Washington. Chelan: Lake Chelan, Lucerne 

(48°12.1′N, 120°35.5′W; 338 m), 29 Jul 1919, A. L. Melander (1♀; USNM).

Type Locality. United States. Washington. 

Chelan: Lake Chelan, Lucerne (48°12.1′N, 120°35.5′W; 

338 m).

Other Specimens Examined. UNITED 

STATES. California. Alpine: Carson Pass (38°41.6′N, 

119°59′W), 28 Jul 1930, H. H. Keifer (1♂; CSCA); Monitor Pass (1.6 km S; 38°40.5′N, 119°37.2′W; 2630 m), 

22–23 Aug 1979, P. Adams, M. S. Wasbauer (1♂; CSCA). 

Contra Costa: Mitchell Canyon, north base of Mount Diablo (37°52.9′N, 121°54.8′W; 300–500 m), 26 Aug 1994, 

M. E. Erwin (2♂, 5♀; CSCA). Modoc: Cedar Pass, Warner 

Mountains (41°33.8′N, 120°16.1′W; 1825 m), 8 Aug 1965 

(9♀; USNM). Nevada: Truckee (39°19.7′N, 120°11′W), 

16 Jul 1916, H. G. Dyar (11♂, 27♀; USNM). San Bernardino: Falls Valley (34°05′N, 116°54.8′W), 10 Jul 1940, 

A. L. Melander (1♂;USNM); Lost Creek (34°10.1′N, 

116°49.5′W), 4 Jul 1958, A. L. Melander (1♂; USNM); 

South Fork Santa Ana River (34°10.3′N, 116°49.8′W), 

18 Jun–2 Aug 1942, 1945, 1947, A. L. Melander (3♂, 

3♀; USNM); Sugar Loaf (34°143.6′N, 116°49.7′W), 21 

FIGURES 100–103. Structures of male terminalia of Trixoscelis tumida Melander (locality unknown): (100) epandrium, surstylus, hypandrium, 

and gonites, lateral aspect; (101) epandrium and surstyli, posterior aspect; (102) gonites, lateral aspect; (103) aedeagus, lateral aspect. Scale = 

0.1 mm.
6 4 • smithsonian contributions to zoology

Sep 1954, J. C. Hall (1♂; USNM); Upper Santa Ana River 

(35°03.5′N, 119°21.8′W), 25–30 Jun 1949, 1956, A. L. 

Melander (2♂; USNM). Toulumne: Pinecrest (38°11.3′N, 

119°59.5′W), 15 Aug 1948, P. H. Arnaud, Jr. (3♂, 1♀; 

USNM); Belle Meadows (38°10′N, 119°56.5′W), 18 Aug 

1948, P. H. Arnaud, Jr. (1♂; USNM). Siskyou: Mount 

Shasta, McBride Springs Campground (41°21.2′N, 

122°17.1′W; 1585 m), 20–22 Jul 1965, 1968, D. D. Munroe (6♂, 3♀; CNC).

Nevada. Douglas: near junction US 395 & 50 to 

Lake Tahoe (39°07.2′N, 119°46.3′W), 15 Jun 1957, R. 

W. Coleman (1♂; WSU). Lyon: Wellington (7 km NW; 

38°45.5′N, 119°22.6′W), 28 May 1974, M. S. Wasbauer, 

J. Slansky (1♂, 1♀; CSCA). Ormsby: Clear Creek Campground (39°06.9′N, 119°53.4′W; 1980 m), 27 Jul 1968, 

D. D. Munroe (1♂; CNC).

Oregon. Baker: Cougar Creek (60 km SE Union; 

44°56.9′N, 117°24.9′W; 1243 m), E. J. Davis (1♂; 

WSU); Lower Goose Creek (58 km SE Union; 44°49.1′N, 

117°27.6′W; 1220 m), 24–31 Aug 1975, E. J. Davis (6♂, 

3♀; WSU); Lower Goose Creek (36 km SE Union; 44°48′N, 

117°26′W; 1350 m), 13–19 Aug 1975, E. J. Davis (4♂, 

2♀; WSU); Velvet Creek (45 km SE Union; 45°01.9′N, 

117°30.1′W; 1438 m), 17–23 Aug 1975 (1♂; WSU). Union: 

Lower Lick Creek (42 km SE Union; 45°07′N, 117°37′W; 

1305 m), 24–31 Aug 1975, E. J. Davis (6♂; WSU).

Washington. Asotin: Anatone (6.5 km S near Fields 

Spring State Park; 46°08.1′N, 117°07.9′W; 1100 m), 12 Aug 

1980, W. J. Turner (1♂; WSU). Chelan: Malaga, Colockum 

Research Unit (47°22.3′N, 120°12.1′W), 11–25 Jun 1970 

(1♂, 1♀; WSU). Okanogan: Conconully, Salmon Meadows 

(48°32.8′N, 119°44.9′W; 1372 m), 5–7 Aug 1975, W. J. 

Turner (2♂, 1♀; WSU); Twisp (6.5 km E; Rt. 20; 48°29.8′N, 

120°07.3′W; Malaise trap CO2), 19 Jul 1972, W. J. Turner, 

W. B. Garnett (1♂; WSU). Yakima: Tieton Ranger Station (5 

km SW; 46°40.6′N, 121°04.6′W; Milk Creek), 16 Jul 1972, 

W. J. Turner, W. B. Garnett (2♂, 1♀; WSU).

Distribution (Figure 104). Nearctic: 

United States (California, Nevada, Oregon, Washington).

Remarks. The distinctive and swollen hind 

basitarsus of males makes this species easy to identify. 

The fore basitarsus, although only slightly swollen, is still 

noticeable. 

The T. claripennis Species Group

Diagnosis. The species of the claripennis species group are distinguished from those of the other species 

groups by the following combination of characters: Head: 

Gena very short to short, gena-to-eye ratio 0.12–0.22, 

only in one species (T. flavens) up to 0.37. Thorax: Wing 

hyaline, maculate in only one species (T. signifera). Abdomen: Male terminalia: Epandrium small and indistinct 

in relation to remainder of abdomen in undissected specimens. Aedeagus sclerotized in bands and complex; preand postgonite fused into one lobe generally armed with 

short setae or setulae along ventral margin.

Remarks. The monophyly of this species 

group is improbable but not beyond question, based on 

the hypothetical phylogenies we have generated. The reduced and fused pre and postgonite complex and distinctive distiphallus can be observed in many Palearctic species 

as well. Two species, T. plebs and T. nitidiventris, show a 

distinctive and unique cluster of spicules on the medial distiphallus. This character is shared with several Palearctic 

species based on illustrations in the Palearctic literature.

Trixoscelis barberi Foster and Mathis, 

new species

FIGURES 13, 105

Diagnosis. Body gray; thorax with two brown 

vittae between dorsocentral setae and along postprotonal 

and notopleural line, 4 rows of acrostichal setae; wing 

hyaline, not smoky and without infuscations; antenna 

mostly yellow, slightly brownish tint in center of basal 

flagellomere; vertex yellowish to light gray microtomentose; gena short, gena-to-eye ratio only 0.17; epandrium 

small and indistinct in relation to remainder of abdomen 

in undissected specimens.

Description. Body length 1.78–2.31 mm.

Head: Eye higher than wide; ocellar triangle light

gray microtomentose; frons bare, yellow becoming darker 

dorsally, parafrons whitish microtomentose; 2 strong, 

reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short 

cruciate postocellar seta; medial vertical seta strong, widely 

separated and convergent; lateral vertical seta long, strong 

and divergent;occiput gray microtomentose with 1–2 rows 

of short dorsoclinate setulae; antenna mostly yellow except 

brown on dorsal half of basal flagellomere; arista brown, 

with sparse hairs. Gena short, gena-to-eye ratio 0.17, white 

microtomentose, bearing 1 row of 2–3 short ventroclinate

setae along ventral edge in addition to a pair of stronger 

convergent oral vibrissae; face white; palpus yellow, clypeus 

small indistinct, yellow. 

Thorax: Mesonotum uniformly gray microtomentose with 2 brown vittae between dorsocentral setae and 
number 637 • 6 5

along postprotonal and notopleural line, sparsely covered 

with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae in 4 somewhat irregular rows; apical scutellar setae about twice length of 

scutellum. Anepisternum with brownish coloration along 

dorsal half or so, mostly bare except for one strong seta on 

posterodorsal corner along with 3–4 much smaller setulae 

in a cluster; katepisternum with 2 longer setae and several 

very short setulae along the posterodorsal edge. Wing hyaline with brown veins. Halter white. Coxae yellow; fore 

femur dark brown to black, slightly swollen; all other femora, tibiae and tarsi yellow except fifth tarsomere darker, 

male hind basitarsus slightly swollen; fore femur with a 

row of longer setae along posterodorsal and posteroventral 

surfaces.

Abdomen: Uniformly dark gray microtomentose 

except extreme posterior edges of sternites lighter; evenly 

setose. Male terminalia (Figure 105): Epandrium small 

and indistinct in relation to remainder of abdomen in undissected specimens; surstylus (Figure 105) long, robust, 

with anterior curvature, strongly setulose, long triangular in posterior view; pre- and postgonites fused into one 

structure, simple spatulate with a row of short but strong 

setae along ventral margin (Figure 105); aedeagus complex sclerotized.

Type Material. The holotype male is labeled 

“PalmSprings CAL[IFORNIA] 24/4/44 ALMelander/

PARATYPE Trixoscelis sagulata Melander [yellow]/

ALMelander Collection 1961 [green stippling on right 

side]/HOLOTYPE ♂ Trixoscelis barberi Foster & Mathis 

FIGURE 104. Distribution map for Trixoscelis tumida Melander.
6 6 • smithsonian contributions to zoology

USNM [red]/USNM ENT 00118096 [plastic bar code 

label].” The holotype is double mounted (pinned from 

ventral side with a minuten mounted in a cardboard 

square), is in excellent condition (abdomen removed and 

dissected; structures in an attached microvial), and is deposited in the USNM. Paratypes are as follows:

UNITED STATES. California. Orange: Corona del 

Mar (33°35.9′N, 117°52.4′W), 28 Dec 1944, A. L. Melander (1♂; USNM This specimen was among the syntypes, now a paralectotype, series for T. sagulata.). San 

Bernardino: Phelan (11.2 km E; Baldy Mesa Road; 

34°26′N, 117°27′W; pan traps), 15–31 May 1982, J. T. 

Huber (2♂, 1♀; DEBU).

Type Locality. United States. California. 

Riverside: Palm Springs (33°49.8′N, 116°32.7′W).

Distribution (Figure 13). Nearctic: 

United States (California).

Etymology. The species epithet, barberi, is a 

Latin genitive patronym to honor and recognize Kevin N. 

Barber for his numerous contributions to the systematics 

of acalyptrate Diptera and for his valuable insights on collecting specimens of Trixoscelis.

Remarks. This species is very closely allied 

with T. claripennis but shows distinct differences in structures of the male terminalia, particularly the surstyli, gonites, and aedeagus.

Trixoscelis claripennis (Malloch)

FIGURES 106–110

Parodinia claripennis Malloch, 1913:276.

Trixoscelis claripennis (Malloch). —Vockeroth, 1965:817 [Nearctic catalog]. —Melander, 1913a:169 [synonymy with frontalis]. —Melander, 

1952:44 [discussion, reversal of synonymy with frontalis]. —Vockeroth, 1965:817 [Nearctic catalog]. —Cole, 1969:433 [distribution, 

diagnosis].

Trixoscelis sagulata Melander, 1952:49. —Vockeroth, 1965:818 [Nearctic catalog]. —Cole, 1969:434 [distribution, diagnosis]. NEW 

SYNONYM

FIGURE105. Structures of male terminalia of Trixoscelis barberi Foster and Mathis 

(California. Orange: Corona del Mar): epandrium, surstylus, gonites, distiphallus, lateral 

aspect. Scale = 0.1 mm.
number 637 • 6 7

Diagnosis. Body gray; thorax microtomentose, with two very faint brown vittae between dorsocentral and supra-alar setae, 4 rows of acrostichal setae; wing 

hyaline, not smoky and without infuscations; antenna 

mostly yellow, slightly brownish tint in center or dorsum 

of basal flagellomere; vertex yellowish to light gray microtomentose; gena short, gena-to-eye ratio only 0.15–0.22; 

male epandrium in undissected specimens dark, shiny.

Description. Body length 1.65–2.75 mm.

Head: Eye higher than wide; ocellar triangle light

gray microtomentose; frons bare, yellow becoming darker 

dorsally, parafrons whitish-silver microtomentose; 2 strong, 

reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short 

cruciate postocellar seta; medial vertical seta strong, widely 

separated and convergent; lateral vertical seta long, strong 

and divergent;occiput gray microtomentose with 1–2 rows 

of short dorsoclinate setulae; antenna mostly yellow with 

only a slight brownish tint in center or dorsum of basal 

flagellomere; arista brown, with sparse hairs. Gena short, 

gena-to-eye ratio 0.15–0.22, whitish yellow microtomentose, bearing 1 row of 2–3 short ventroclinate setae along

ventral edge in addition to a pair of stronger convergent 

oral vibrissae; face white; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum uniformly gray microtomentose except for two very faint brown vittae between 

dorsocentral and supra-alar setae, sparsely covered with 

setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae in 4 somewhat irregular 

rows; apical scutellar setae about twice length of scutellum. Anepisternum with brownish coloration along dorsal 

half or so, mostly bare except for one strong seta on posterodorsal corner along with 3–4 much smaller setulae in a 

cluster; katepisternum with 2 longer setae and several very 

short setulae along the posterodorsal edge. Wing hyaline 

with yellowish veins. Halter white to yellow. Coxae yellow, 

fore femur dark brown to black, slightly swollen; all other 

femora and tibiae yellow, tarsi darker; fore femur with a 

row of longer setae along posterodorsal and posteroventral 

surfaces.

Abdomen: Uniformly dark gray microtomentose

except extreme posterior edges of sternites lighter; evenly 

setose. Male terminalia (Figure 106–109): Epandrium 

dark, shiny; surstylus (Figure 106) short triangular in posterior view evenly endowed with setae; pre- and postgonites fused into one structure, simple spatulate with row of

short but strong setae along ventral margin (Figures 106, 

108); basiphallus (Figure 109) covered with weak setulae, 

distiphallus trilobed, complex (Figures 106, 107). Female 

terminalia: Seventh tergite and sternite forming a strong, 

tight ring; spermathecae square-cylindrical; eighth sternite 

without lateral lobes; hypoproct without short, strong

setae; epiproct with only weak setulae.

Type Material. Malloch described T. claripennis from nine specimens that were collected in Arizona 

by H. S. Barber. The specimen he designated as “Type” is a 

male in excellent condition and is labeled “Williams, 29-5, 

ARIZ[ONA]/Type No. 15557, U.S.N.M.[red]/Parodinia 

claripennis Malloch Type [handwritten on white label with 

black border].” The holotype is double mounted (glued to 

a paper triangle), is in good condition (the wing tips are 

slightly damaged but otherwise the specimen is in good 

condition), and is deposited in the USNM (15557). We 

located six of the other eight specimens cited by Malloch 

as paratypes. Malloch stated that he had eight paratypes 

from Williams, Bright Angel, and Flagstaff, Arizona. We 

have one male and five females collected by H. S. Barber 

from both Williams and Flagstaff, Arizona. Four of the 

specimens from Williams have the same collecting data 

as the holotype. We have not located the specimens from 

Bright Angel. The paratypes are as follows: 

Arizona. Coconino: Flagstaff (35°11.9′N, 111°39.1′W), 

4 Jul, H. S. Barber (1♀; USNM); Williams, 7 Jun, H. S. 

Barber (1♀; USNM); Williams (35°15′N, 112°11.5′W), 29 

May, H. S. Barber (1♂, 3♀; USNM).

Coquillett (1902) had earlier identified these same 

nine specimens from Arizona as T. costalis, which he had 

originally described as Rhicnoessa costalis from the Galápagos Islands (Coquillett, 1901). The holotype specimen 

of R. costalis is destroyed. There is a handwritten label (by 

C. W. Sabrosky) in the type tray of this species, indicating 

that this specimen was determined to be lost on 27 January 1949. In Coquillett’s original description he indicated 

that there were two specimens but does not say where the 

second was deposited.

Regarding T. costalis, Malloch (1913:276) wrote that 

there was only one specimen in the USNM and that it was 

“not in very good condition.” He described the nine Arizona specimens as T. claripennis based on significant differences in the wings, T. costalis having some infuscation 

along the costal margin and T. claripennis having hyaline 

wings.

We have been fortunate to have access to nearly 100 

specimens of what we have identified as T. costalis from 

fieldwork done by S. Peck and B. J. Sinclair in the 1980s 

and 1990s and deposited in the Canadian National Collection. We provided a detailed treatment with illustrations of the male terminalia earlier in this study.
6 8 • smithsonian contributions to zoology

Melander (1952) based T. sagulata on 33 specimens 

(17♂, 16♀). He wrote (p. 49) that the “types” are from 

“Whitewater Canyon, California, November 11, 1944.” 

There are three males and one female that are so labeled. 

Two of the males are mounted on the same minuten. We 

designate the top one as the lectotype as it is in the best 

condition of the three specimens. The lectotype specimen 

is labeled “Whitewater Can[yon] CALIF[ORNIA] 11/

XI/44 A. L. Melander/HOLOTYPE Trixoscelis sagulata

Melander [red]/Trixoscelis sagulata Melander [white handwritten]/LECTOTYPE ♂ Trixoscelis sagulata Melander 

Foster & Mathis USNM/USNM ENT 00118093 [plastic 

bar code label].” The lectotype is double mounted (pinned 

from ventral side with a minuten mounted in a cardboard 

square; another specimen below the lectotype has been dissected; structures of the male terminalia are in an attached 

microvial), is in good condition (right wing missing), and 

is deposited in the USNM. Paralectotypes are as follows:

UNITED STATES. Arizona. Cochise: Huachuca 

Mountains (31°29.3′N, 110°24.5′W), 3 May 1948, A. L. 

Melander (1♂; USNM); Huachuca Mountains, Miller 

Canyon (31°25.8′N, 110°14.2′W), 2 May 1948, A. L. 

Melander (2♀; USNM). Pinal: Superior (33°17.6′N, 

111°05.8′W), 13 Apr 1935, A. L. Melander (1♂; USNM).

FIGURES 106–109. Structures of male terminalia of Trixoscelis claripennis (Malloch) (California. 

Los Angeles: Whitewater Canyon): (106) epandrium, surstylus, gonites, distiphallus, lateral aspect; 

(107) distiphallus, lateral posterior aspect; (108) gonites, lateral aspect; (109) aedeagus, lateral aspect. Scale = 0.1 mm.
number 637 • 6 9

California. Los Angeles: Whitewater Canyon 

(34°21.4′N, 118°21.2′W), 11 Nov 1944, A. L. Melander 

(2♂, 1♀; USNM). Riverside: Cathedral City (33°46.8′N, 

116°27.9′W), 22–23 Nov 1944, A. L. Melander (1♂, 1♀; 

USNM); Devils Garden (33°58.2′N, 116°37.1′W), 26 Nov 

1946, A. L. Melander (1♀; USNM); Indio (33°43.2′N, 

116°13′W), 13 Dec 1944, A. L. Melander (2♀; USNM); 

Morongo Valley (33°57.6′N, 116°31.5′W), 26 Nov 1946, 

A. L. Melander (1♂; USNM); Palm Springs (33°49.8′N, 

116°32.7′W), 24 Apr–22 Nov 1934, 1943, 1944, A. L. 

Melander (7♂, 1♀; USNM); Salton Beach (33°28.2′N, 

115°53′W), 12 Nov 1945, A. L. Melander (1♀; USNM). 

San Bernardino: Oak Glen (34°03′N, 116°56.9′W), 19 

Jun 1946, A. L. Melander (1♀; USNM). San Diego: Borrego, Palm Canyon (33°13.2′N, 116°20.1′W), 7–10 Nov 

1934, 1945, A. L. Melander (1♂, 1♀; USNM); La Jolla 

(32°50.8′N, 117°16.5′W), 29 Dec 1934, A. L. Melander 

(1♂, 4♀; USNM).

Utah. Washington: Zion National Park (37°18′N, 

113°03.1′W), 20 Apr 1935, A. L. Melander (1♂, 1♀; 

USNM).

Type Locality. United States. Arizona. Coconino: Williams (35°15′N, 112°11.5′W).

Other Specimens Examined. CANADA. 

British Columbia. Oliver (49°10.8′N, 119°33.9′W), 14 

May 1959, E. E. MacDougall (1♂; CNC).

MEXICO. Baja California. Rancho San Ignacio (26 

km E Rosarito; 32°20.9′N, 117°02.5′W), 26–27 Mar 

1982, J. Slansky, M. S. Wasbauer (1♀; CSCA).

Baja California Sur: Guillermo Prieto (21 km SW; 

27°50′N, 113°19′W; Malaise trap), 3–5 Apr 1982, M. S. 

Wasbauer (2♀; CSCA).

UNITED STATES. Arizona. Pinal: Oracle (12 km S; 

32°36′N, 110°46.2′W), 28 Apr 1967, D. M. Wood (1♀; 

CNC).

California. Riverside: Palm Desert (33°43.3′N, 

116°22.4′W; 915 m), 4 Apr 1955, W. R. Richards (1♀; 

CNC); Rancho Mirage (33°44.4′N, 116°24.8′W), 6 Apr 

1955, W. R. M. Mason (2♀; CNC); Thousand Palms 

(33°48.7′N, 116°22.6′W), 20 Mar–5 Apr 1955, W. R. 

Richards (3♂, 11♀; CNC); Thousand Palms, Willis Palms 

Oasis (33°49′N, 116°23.6′W), 18 Mar 1955, W. R. M. 

Mason (1♀; CNC). San Bernardino: Twenty-nine Palms 

(34°08.1′N, 116°03.3′W), 4 Oct 1949, A. L. Melander 

(1♀; USNM). San Diego: Borrego (north end Clark Lake; 

33°20.3′N, 116°16.7′W), 23 Mar 1978, P. Adams, J. Slansky, M. S. Wasbauer (2♂, 3♀; CSCA).

Nevada. Lyon: Wellington (7 km NW; 38°45.5′N, 

119°22.6′W), 28 May 1974, J. Slansky, M. S. Wasbauer 

(1♀; CSCA).

Distribution (Figure 110). Nearctic: 

Canada (British Columbia), Mexico (Baja California, 

Baja California Sur), United States (Arizona, California, 

Nevada, Utah).

Remarks. The synonymy proposed herein of 

T. sagulata with T. claripennis is based on essentially identical structures of the male terminalia of the syntype, now 

a paratype of T. sagulata, which is double mounted on the 

same pin as the lectotype (itself undissected), with those of 

the topotypical paratype of T. claripennis. The aedeagus 

of the T. claripennis paratype is missing but the terminalia 

are otherwise identical to T. sagulata. They are also essentially identical in external characters. The differences 

between T. claripennis and T. flavida are rather slight: the 

postgonite of T. claripennis is much broader than T. flavida and the aedeagus of T. claripennis lacks or has much 

reduced “teeth” on the primary lobe. The latter character can vary, depending on the orientation of the specimen, etc. The aedeagus of T. flavida also has conspicuous 

“teeth” on the tertiary lobe, whereas the tertiary lobe of 

T. claripennis has much shorter “teeth.” There seems to 

be some slight variation in the width of the postgonite of 

T. flavida. We have observed a much narrower postgonite 

in some specimens (Figure 125). Finally, the male basal 

flagellomere of T. flavida is entirely bright yellow while 

that of T. claripennis shows a brown tint in the center of 

the outer lateral surface.

Trixoscelis flavens Melander

FIGURES 111–115, 118–119

Trixoscelis flavens Melander, 1952:45. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Head and thorax entirely brownish yellow; 4 rows of acrostichal setae, proepimeral seta 

present; wing hyaline with no infuscations; antenna completely yellow except basal flagellomere brown anterior to 

base of arista; vertex yellow; gena high, gena-to-eye ratio 

0.37; abdomen black; male epandrium in undissected 

specimens yellow.

Description. Body length 2.65–3.39 mm.

Head (Figures 118, 119): Higher than wide. Eye 

slightly higher than wide; ocellar triangle yellow microtomentose; frons bare, uniformly yellow; parafrons silveryyellow microtomentose; 2 strong, reclinate parafrontal setae; 

ocellar setae 1 strong pair, positioned at level of or anterior 

to anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; 
7 0 • smithsonian contributions to zoology

medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent;occiput 

rather wide, yellow microtomentose, with 1 row of short 

dorsoclinate setulae in addition to several scattered setulae 

dorsally and ventrally; antenna completely yellow except 

basal flagellomere brown anterior to base of arista; arista 

brown, with sparse hairs. Gena high, gena-to-eye ratio 

0.37, yellow microtomentose, bearing a row of 3–4 setulae

along ventral margin in addition to a pair of strong convergent oral vibrissae; face yellow; palpus yellow, clypeus small 

indistinct, yellow.

Thorax: Mesonotum light brownish yellow, covered with many minute setae; acrostichal setae in 4 irregular 

rows; apical scutellar setae not more than twice length of 

scutellum. Anepisternum mostly bare except for one strong 

seta on posterodorsal corner along with 3–4 much smaller 

setulae in a cluster; katepisternum with 2 longer setae and 

1–2 very short setulae along the posterodorsal edge. Wing 

hyaline. Halter yellow. All coxae, femora, tibiae, and tarsi 

yellow; fore femur with a row of longer setae along posterodorsal and posteroventral surfaces.

Abdomen: Uniformly gray to black microtomentose; evenly setulose. Male terminalia (Figures 111–114): 

Epandrium in undissected specimens yellow; surstylus 

(Figures 111, 112) robust, roughly triangular in posterior 

view, slightly curved anteriorly in lateral view, ending in 

dark, thick point, nearly bare with only few weak setulae; pre- and postgonites separate, pregonite (Figure 111) 

a simple, spatulate lobe, with few short thick setae along 

ventral margin, postgonite a small inconspicuous lobe attached to the posterior edge of the hypandrium; distiphallus 

complex, with three long thin lobes, somewhat resembling 

FIGURE 110. Distribution map for Trixoscelis claripennis (Malloch).
number 637 • 7 1

a pitchfork with badly bent tines, darkly sclerotized (Figures 113, 114). Female terminalia: Spermathecae 4× longer than wide; eighth sternite with small, lateral setaceous 

lobes; hypoproct without short, strong setae, epiproct with 

only weak setulae.

Type Material. Trixoscelis flavens was 

described from a single female, the holotype, that is labeled “Lind [46°58.3′N, 118°36.9′W] WASH[INGTON. 

Adams:], 11 Jun 1919. FW Carlson/HOLOTYPE Trixoscelis flavens Melander [red]/A. L. Melander Collection 

FIGURES 111–114. Structures of male terminalia of Trixoscelis flavens Melander (Utah. Emery: Wild Horse Creek): (111) epandrium, cercus, 

surstylus, and gonites, lateral aspect; (112) epandrium and surstyli, posterior aspect; (113) aedeagus and aedeagal apodeme, lateral aspect; (114) 

distiphallus, dorsoblique aspect. Scale = 0.1 mm.
7 2 • smithsonian contributions to zoology

1961 [white label with green stippling on right side].” The 

holotype is directly pinned, is in excellent condition, and 

is deposited in the USNM.

Type Locality. United States. Washington. 

Adams: Lind (46°58.3′N, 118°36.9′W.

Other Specimens Examined. UNITED 

STATES. Arizona. Navajo: Navajo National Monument 

(36°41.2′N, 110°32.2′W; 2225 m), 26–27 Jul 1979, S. 

Peck, J. Peck (1♂; DEBU).

Utah. Emery: Wild Horse Creek (2.4 km NW Wild 

Horse Butte; 38°34.7′N, 110°43.2′W; 1495 m), 26–27 Jul 

1982, A. K. Menke, Kurt Menke (26♂, 16♀; USNM).

Washington. Adams: Lind (46°58.3′N, 118°36.9′W), 

5 Jun 1919, F. W. Carlson (2♀; WSU).

Distribution (Figure 115). Nearctic: 

United States (Arizona, Utah, Washington).

Remarks. The validity of this species had been 

uncertain, awaiting males that were conspecific with the 

female holotype. We were fortunate to find a large series of 

males and females that A. S. Menke and Kurt Menke collected in Utah. The females match well with the holotype, 

and we assume that this series is conspecific with the holotype. This species is almost entirely yellowish except for 

the abdomen, which is light gray. On the basis of the high 

gena and the shape of the head, this species would seem to 

be closely related to T. nuda or to T. cinerea. The male epandrium and surstylus also show an affinity with those two 

species; the aedeagus, however, is quite complex compared 

FIGURE 115. Distribution map for Trixoscelis flavens Melander.
FIGURES 116–121. Photographs of heads: (116) Trixoscelis tumida, anterior aspect; (117) same, lateral aspect; (118) T. flavens, anterior aspect; (119) same, lateral aspect; (120) T. flavida, anterior aspect; (121) same, lateral aspect 
7 4 • smithsonian contributions to zoology

with that of T. nuda and T. cinerea and is strong evidence 

that T. flavens is part of the T. claripennis species group.

Trixoscelis flavida Melander

FIGURES 120–126

Trixoscelis flavida Melander, 1952: 45. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:434 [distribution, diagnosis].

Trixoscelis frontalis of authors, nec Fallén [misidentification]. —Melander, 

1913a:169 [discussion]. —Melander, 1913b:296 [key]. —Vockeroth, 

1965:818 [Nearctic catalog].

Diagnosis. Body gray, rarely mostly pale; 4 

rows of acrostichal setae; wing hyaline, not smoky and 

without infuscations; antenna usually mostly yellow, basal 

flagellomere may be brown in center in females, entirely 

yellow in males; vertex yellowish to light gray microtomentose; gena short, gena-to-eye ratio only 0.15; male 

epandrium in undissected specimens usually gray microtomentose, some specimens with yellowish epandrium.

Description. Body length 1.83–2.93 mm.

Head (Figures 120, 121): Eye higher than wide; 

ocellar triangle light gray microtomentose; frons bare, yellow becoming darker dorsally, parafrons whitish microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 

1 strong pair, positioned at level of or anterior to anterior 

ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical 

seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent;occiput gray microtomentose with 1–2 rows of short dorsoclinate setulae; 

antenna usually yellow, basal flagellomere may be brown 

in center in females, entirely yellow in males; arista brown, 

with sparse hairs. Gena short, gena-to-eye ratio 0.15, 

whitish-yellow microtomentose, bearing 1 row of 2–3 short 

ventroclinate setae along ventral edge in addition to a pair 

of strong convergent oral vibrissae; face white; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than 

the dorsocentral setae, a distinct brown area on the dorsal 

half of the proepisternum, anepisternum, and the extreme 

ventral portion of the postpronotal lobe. Dorsocentral 

setae 5(2+3); acrostichal setae in 4 irregular rows; apical 

scutellar setae about 3× length of scutellum. Anepisternum 

mostly bare except for one strong seta on posterodorsal 

corner along with 3–4 much smaller setulae in a cluster; 

katepisternum with 2 longer setae and several very short 

setulae along the posterodorsal edge. Wing hyaline with 

yellowish veins. Halter white to yellow. Coxae yellow, fore 

femur dark brown to black (rarely yellow), slightly swollen, 

fore tibia and tarsi dark brown; all other femora and tibiae 

yellow, tarsi darker; fore femur with a row of longer setae 

along posterodorsal and posteroventral surfaces.

Abdomen: Uniformly dark gray microtomentose

except extreme posterior edges of sternites lighter; evenly 

setose. Male terminalia (Figures 122–125): Epandrium 

usually uniformly gray microtomentose but may rarely 

be yellow, details as in Figures 122, 123; surstylus small, 

somewhat teardrop shaped, endowed with many long setae 

along margin (Figures 122, 123); pre- and postgonites (Figures 124, 125) fused, oblong, with 2 rows of short setae

along ventral margin; aedeagus (Figures 122, 124) complex, appearing trilobed, partially sclerotized. Some variation exists in the width of the fused pre- and postgonite 

(Figure 124, 125). Female terminalia: Seventh tergite and 

sternite forming strong, tight ring; spermathecae spherical; 

eighth sternite with reduced lateral lobes each with 3–4 

setae; hypoproct without short, strong setae; epiproct with 

only weak setulae.

Type Material. Melander described T. flavida from a type series of seven specimens without designation of a holotype. He labeled one of these specimens, 

however, as “type” and it is from Mill Creek in Walla 

Walla, Washington. There are three specimens so labeled 

in the USNM, two males and one that is missing its abdomen. We have designated as lectotype one of the males 

that is labeled “Walla Walla, W[ASHINGTO]N[. Walla 

Walla: ], Mill Creek [46°02.3′N, 118°28.7′W], 2–6 July 

22, A. L. Melander/PARATYPE Trixoscelis flavida Melander [yellow]/A. L. Melander Collection 1961 [white 

label with green stippling on right side]/LECTOTYPE ♂

Trixoscelis flavida Melander Foster & Mathis USNM/

USNM ENT 00118088 [plastic bar code label].” The lectotype is double mounted (pinned ventrally on minuten), 

is in good condition, and is deposited in the USNM. Paralectotypes are as follows:

UNITED STATES. Washington. Walla Walla: Walla 

Walla, Mill Creek (46°02.3′N, 118°28.7′W), 2–6 July 

1922, A. L. Melander (1♂, 1 unknown sex; USNM). 

Whitman: Pullman (46°43.9′N, 117°10.8′W), 16 Jun 

1912, A. L. Melander (1♂; USNM). Pullman (46°43.9′N, 

117°10.8′W), 16 Jun 1918, A. L. Melander (1♀; USNM). 

Union Flat (46°49.6′N, 117°59.9′W), 16 Jun 1916, A. L. 

Melander (1♀; USNM).

Oregon. Marion: Salem (44°56.6′N, 123°02.1′W), 4 

Jul 1917, A. L. Melander (1♀; USNM).

Type Locality. United States. Washington. 

Walla Walla: Mill Creek (46°02.3′N, 118°28.7′W).
number 637 • 7 5

FIGURES 122–125. Structures of male terminalia of Trixoscelis flavida Melander (labeled as T. frontalis) (Washington. Walla Walla: 

Mill Creek): (122) epandrium, cercus, surstylus, gonites, and aedeagus, lateral aspect; (123) epandrium and surstyli, posterior aspect; 

(124) cercus, aedeagus, aedeagal apodeme, and gonites, lateral aspect; (125) gonites, lateral aspect (California. San Bernardino: Lytle 

Creek). Scale = 0.1 mm.
7 6 • smithsonian contributions to zoology

Other Specimens Examined. CANADA. 

Alberta. Oyen (51°21.2′N, 110°29′W), 22 Jul 1979, D. H. 

Pengelly (2♀; DEBU).

British Columbia. Boundary Creek Provincial Park 

(49°04′N, 118°46′W), 30 Jul 1980, G. Gibson (1♂, 1♀; 

DEBU); Bowser (49°26′N, 124°40′W), 31 May–20 Jun 

1955, R. Coylee, G. E. Shewell, J. R. McGillis (10♂, 15♀; 

CNC); Cranbrook (49°30′N, 115°46′W), 16 Jul 1980, G. 

Gibson (3♂, 3♀; DEBU); Cranbrook (15 km S; 49°29′N, 

115°46′W; flight intercept trap), 27 Jun–4 Jul 1980 (1♂; 

DEBU); Cranston (20 km E; 49°03′N, 117°56′W), 1 Jul 

1980, S. A. Marshall (1♀; DEBU); Cultus Lake (49°03.3′N, 

121°59.3′W), 15 Jul 1948, H. R. Foxlee (1♂; CNC); Gagnon Road (9.6 km W of Terrace; 54°31′N, 128°36′W), 9 

Jul 1960, C. H. Mann (1♀; CNC); Goldstream (48°29′N, 

123°33′W), 6–16 Aug 1927, 1963, W. Downes (3♀; 

CNC); Kamloops (50°40.6′N, 120°20.5′W), 11 Jun 

1972, N. L. H. Krauss (1♀; USNM); Kaslo (49°54.2′N, 

116°56.1′W), 25 Jun–7 Jul, R. P. Currie (3♂, 4♀; USNM); 

Keremeos (49°12.4′N, 119°49.7′W), 19 Jul 1910, A. L. 

Melander (1♀; USNM); Kleanza Creek (24 km E. of Terrace; 54°36′N, 128°25′W), 17 Jun–13 Jul 1960, C. H. 

Mann, R. Pilfrey, J. G. Chillcott (2♂, 10♀; CNC); Ladysmith (48°59′N, 123°49′W), 2 Jun 1955, R. Coylee (1♂, 

2♀; CNC); Langford (48°27′N, 123°30′W), 7–8 Aug 

1962, 1963, D. Evans (2♀; CNC); Lytton, 40 km N., 600 

m (50°31′N, 121°43′W; alfalfa, sage, clover, and mustard), 

13 Jun 2000, H. Goulet, J. Gillespie (24♂, 28♀; DEBU); 

Lytton (50°40′N, 121°46′W; 200 m) (alfalfa, sage, rose, 

and cactus), 13 Jun 2000, H. Goulet, J. Gillespie (6♂, 

10♀; DEBU); Metchosin (48°23′N, 123°32′W), 5 Sep 

1963 (2♂, 1♀; CNC); Merritt, Midday Valley (50°06.7′N, 

120°47.5′W; Pinus ponderosa), 9 Jul 1923, R. Hopping (6♀; CNC); Mission City (49°08′N, 122°18′W), 15 

Jun 1953, G. J. Spencer (1♂; CNC); Oliver (49°10.8′N, 

119°33.9′W), 13–14 May 1959, E. E. MacDougell (1♂, 

2♀; CNC); Oliver, Vaseaux Lake (49°11′N, 119°33′W), 

28 May 1959, L. A. Kelton (2♀; CNC); Osoyoos, Haynes 

Ecological Reserve (49°02′N, 119°27′W; pan trap; Purshia/Aristida steppe), 20 May–14 Jun 1987, G. G. Cannings (3♀; DEBU); Penticton (49°30′N, 119°35′W), 5 

Jul–21 Aug 1931, 1967, R. D. Bird, J. R. Vockeroth (3♂, 

2♀; CNC); Qualicum Bay (49°24′N, 124°38′W), 21 Jun 

1955, 19 Jul 1955, G. E. Shewell (9♂, 18♀; CNC); Robson 

(49°20′N, 117°41′W), 4 Apr–30 Jul 1947, 20 Aug 1948, 

10 Jun 1950, 8 Jun–19 Jul 1952, H. R. Foxlee (3♂, 13♀; 

CNC); Royal Oak (48°29′N, 123°23′W), 18 Aug 1917, 

W. Downes (1♀; CNC); Saanich (48°33′N, 123°22′W), 

9 Jun 1927, J. Stanley (2♂, 5♀; CNC); Shames (29 km 

SW of Terrace; 54°25′N, 128°56′W), 17–24 Jul 1960, 

B. Heming, C. H. Mann (1♀; CNC); Skagit (F.I.) (13 km 

W Hope; 49°23′N, 121°26.8′W), 8–28 Jul 1980, S. A. 

Marshall (1♀; DEBU); Summerland (49°36′N, 119°40′W), 

18 Jun–15 Sep 1930, 1931, A. N. Gartnell, A. A. Dennys (2♀; CNC); Terrace (54°31′N, 128°36′W), 10 Jun–21 

Jul 1960, W. R. Richards, C. H. Mann (3♀; CNC); Terrace (52 km SW; 54°29′N, 128°37′W), 6 Jun 1960, J. G. 

Chillcott (1♂, 1♀; CNC); Vancouver Island (48°22.7′N, 

123°43′W), 12 Jul 1924, A. L. Melander (1♂; USNM); 

Vancouver Island, Deep Bay (49°30′N, 124°13′W), 16 

Jun 1955, 1960, R. Coyles (3♂, 4♀; CNC); Vernon 

(50°15.5′N, 119°16′W), 1–2 Jul 1937, D. B Waddell, 21 

Aug–3 Sep 1931, R. D. Bird (6♂, 4♀; CNC); Victoria 

(48°26′N, 123°21′W), 10 Jul–12 Sep 1924, 1963, A. L. 

Melander (2♂; CNC, USNM); Zymoetz (9.6 km E Terrace; 54°33′N, 128°29′W; on flowers and leaves of Devil’s 

Club), 3 Jun 1960, J. G. Chillcott (2♀; CNC).

MEXICO. Baja California. El Crucero (25.7 km SE 

Laguna Chapala; 29°23′N, 114°22′W; 600 m), 13 Apr 

1983, M. S. Wasbauer (1♂, 1♀; CSCA). Rancho San Ignacio (26 km E Rosarito; 32°20.9′N, 117°02.5′W), 26–27 

Mar 1982, J. Slansky, M. S. Wasbauer (1♀; CSCA).

Baja California Sur: Arroyo San Gregorio (13 km 

WNW of La Purísima; 26°13.6′N, 112°21.8′W), 24 Apr 

1983, M. S. Wasbauer (1♂, 1♀; CSCA).

UNITED STATES. Arizona. Apache: Alpine Luna 

Lake (33°49.7′N, 109°04.9′W; 2410 m; pine meadows), 9–14 Jul 1979, S. and J. Peck (6♀; DEBU). Cochise: Chiricahua Mountains, Herb Martyr Forest Camp 

(31°52.3′N, 109°14′W; 1875 m), 30 Apr 1979, K. N. 

Barber (1♂, 2♀; DEBU); Portal, Southwestern Research 

Station (8 km SW of Portal; 31°52.9′N, 109°12.2′W; 

1631 m), 23 May–5 Jun 1967, C. W. Sabrosky (2♀; 

USNM). Coconino: Flagstaff, Oak Creek Canyon, Sterling Canyon (35°01.5′N, 111°44.2′W; 1800 m; riparian 

woods), 17–25 Jul 1979, S. and J. Peck (4♀; DEBU); 

Flagstaff (35°11.9′N, 111°39.1′W; 2165 m; ponderosa 

pine meadow, Malaise trap), 18–25 Jul 1979, S. Peck, J 

Peck (11♂, 7♀; DEBU). Maricopa: Phoenix (33°34.3′N, 

112°05.3′W), 11 May 1954, CDC (1♀; USNM). Mohave: Littlefield (36°53.1′N, 113°55.8′W), 27 Mar 1931, 

E. W. Davis (1♀; USNM). Navajo: Holbrook (24 km SE; 

34°54′N, 110°09′W; 1920 m; grassland carrion traps), 

14–16 Jul 1979, S. Peck, J. Peck (1♂; DEBU); Navajo 

National Monument (36°41.2′N, 110°32.2′W; 2225 m; 

pinion-juniper, carrion traps), 26–27 Jul 1979, S. Peck,

J. Peck (2♂; DEBU); Winslow (35°01.5′N, 110°41.8′W; 

Little Colorado River crossing at Route 180), 17 May 

1976, G. A. Foster (4♀; USNM). Pima: Madera Canyon, 

Dutch John Spring (31°43.8′N, 110°51.7′W), 3 Jun 1991, 
number 637 • 7 7

J. E. Swann (1♂; DEBU). Yavapai: Congress (34°09.8′N, 

112°51′W), 23–26 Apr 1967, D. M. Wood (1♀; CNC).

California. Alameda: Alameda (37°45.9′N, 

122°14.5′W; salt marsh), 5 May 1908 (2♀; ANSP); Berkeley (37°52.3′N, 122°16.4′W), 16 May-Sep 1907, 1921, 

1932, J. M. Aldrich, C. Fuchs, A. H. Sturtevant (2♂, 4♀; 

USNM); Berkeley (37°52.3′N, 122°16.4′W), 30 Apr 1968, 

D. D. Munroe (5♂, 13♀; CNC); Berkeley Hills (37°53′N, 

122°14.3′W), 11 Apr–9 May 1908 (3♂, 2♀; ANSP). Live 

Oak Park (37°53.1′N, 122°16.1′W), 7 Jun 1945, A. L Melander (1♀; USNM). Contra Costa: Lafayette (37°53.1′N, 

122°07.1′W), 11 May 1963, L. G. Bock (1♀; WSU). Del 

Norte: Crescent City (30 km N; 41°45.5′N, 124°12.1′W), 

28 Jun 1972, G. C. Steyskal (4♂; USNM); Smith River 

(41°56.2′N, 124°12.2′W; Pherocon apple maggot trap), 

3–16 Sep 1983 (1♀; CSCA). El Dorado: Placerville 

(38°43.8′N, 120°47.9′W; ex. pear tree), 19 May 1930 

(1♀; CSCA). Fresno: Sanger (36°42.5′N, 119°33.4′W), 

24–25 Apr 1949, R. E. Ryckman (1♂, 2♀; USNM); Sierra 

National Forest (37°15′N, 119°11.2′W), 7 Aug 1955, 

C. R. Quick (1♀; USNM). Humboldt: Garberville (south 

fork Eel River; 40°38.5′N, 124°18.7′W), 7–8 Aug 1982, 

M. S. Wasbauer (1♀; CSCA); Korbel (40°52.2′N, 

123°57.5′W), 12 Jun 1960, T. R. Haig (1♀; CSCA); Redwood Creek, Bair’s Reach (41°17.5′N, 124°05.5′W), 19 

Jun, H. S. Barber (1♂; USNM). Imperial: Ogilby Road, 

Chocolate Mountains (5 km S junction with highway 78; 

33°28′N, 115°35′W; Malaise trap), 16–22 Oct 1977, 

P. Adams, J. Slansky, M. S. Wasbauer (2♂, 4♀; CSCA); 

Palo Verde (33°26′N, 114°43.9′W), 7 Apr 1949, W. W. 

Wirth (1♂; USNM). Inyo: Falls Spring (35°51.3′N, 

117°22.9′W), 25 Apr 2002, D. Mathis, W. N. Mathis (1♂; 

USNM); Trona Golf Club (35°49.7′N, 117°19.8′W), 25 

Apr 2002, D. Mathis, W. N. Mathis (1♂; USNM). Kern: 

Arvin (35°12.6′N, 118°49.7′W), 14 Mar 1935, A. L. Melander (1♂, 1♀; USNM); Bakersfield (32 km NE, Cow Flat 

Creek; 35°30.1′N, 118°41.6′W; 500 m), 25 Apr 2002, 

S. D. Gaimari (1♂, 3♀; CSCA); Bakersfield (25 km W, 

Kern River; 35°30.4′N, 119°25.8′W; 50 m; sweeping riverside vegetation), 24 Apr 2002, S. D. Gaimari (31♂, 20♀; 

CSCA); Onyx (11.2 km E; 35°41.4′N, 118°13′W), 12 Jun 

1961, H. F. Howden (1♀; CNC). Lake: Clear Lake 

(38°57.5′N, 122°37.6′W), 18 Jun 1935, A. L. Melander 

(1♂, 2♀; USNM); McLaughlin Reserve (38°51′N, 

122°25′W), 30 Apr 2005, K. A. Williams (1♂; CSCA). 

Lassen: Wendel (40°20.9′N, 120°13.9′W; on alfalfa), 

4 Jun 1931, A. C. Browne (1♀; CSCA). Los Angeles: 

Camp Angelus (34°25.3′N, 118°31.4′W; Ceanothus), 

22–30 May 1947, A. L. Melander (11♂, 3♀; USNM); Claremont (34°05.8′N, 117°43.2′W), Baker, M. Metz (1♂, 

3♀; USNM); Claremont (34°05.8′N, 117°43.2′W), Essig 

(1♂, 2♀; USNM); Gorman (8 km SE; 34°47.5′N, 

118°51.1′W), 30 Mar 1968, M. S. Wasbauer (1♀; CSCA); 

La Crescenta, base of Eagle Canyon (34°23.5′N, 

118°23.3′W; 750–850 m), 26 Apr 2002, S. D. Gaimari 

(12♂, 17♀; CSCA); Mojave (34°36.3′N, 117°49.8′W), 11 

Nov 1914, A. Wetmore (1♀; USNM); Mojave Desert, Big 

Rock Wash (34°40′N, 117°52.3′W), 13 May 1944, A. L. 

Melander (1♂; USNM); Mojave Desert, Lovejoy Buttes 

(34°36.1′N, 117°51.1′W), 25 May 1947, A. L. Melander 

(1♀; USNM); Mojave Desert, Lovejoy Springs (34°36.3′N, 

117°49.8′W), 10 May 1944, A. L. Melander (1♂, 1♀, 

USNM); Pasadena (34°08.9′N, 118°08.7′W), 25 Mar 

1929, A. H. Sturtevant (1♀; USNM); San Clemente Island 

transect, Thirst to White Rock (32°53.5′N, 118°26.4′W), 

10 May 1973, D. R. Miller (2♂; USNM); San Clemente 

Island, China Canyon (32°55′N, 118°30′W; 183 m; ex. 

Prunus), 13 May 1973, D. R. Miller (2♂; USNM); Saugus 

(34°24.7′N, 118°32.4′W), 12 May 1918, F. M. Jones (1♂; 

ANSP); Snow Creek, Whitewater (34°02′N, 117°50.3′W), 

7–24 Mar 1955, W. R. M. Mason (4♂; CNC); Whitewater 

(34°21.4′N, 118°21.2′W), 9 Apr 1955, 16 May 1954, 

A. L. Melander (1♂, 1♀; USNM). Marin: Alpine Lake 

(37°56.4′N, 122°38.3′W; Lily Pond; 460 m), 12 May–19 

Jul 1970, D. D. Munroe (4♂, 2♀; CNC); Inverness 

(38°06.1′N, 122°51.4′W), 10 May 1968, D. D. Munroe 

(2♂, 4♀; CNC); Novato (38°06.5′N, 122°34.2′W), 18 

May 1969, I. Baker (1♀; USNM); Point Reyes (38°0.1′N, 

122°59.8′W), 17–19 Apr 1980, S. A. Marshall (3♂, 1♀; 

DEBU). Mendocino: Fort Bragg (39°26.8′N, 123°48.3′W), 

2 Jul 1973, J. R. Vockeroth (2♂, 5♀; CNC); Hopland 

(Russian River; 38°58.4′N, 123°07′W), 4 May 1968, W. J. 

Turner (1♂; WSU). Modoc: Adin Pass (41°20.8′N, 

120°55.3′W), 6 Jul 1979, T. R. Haig (1♀; CSCA); Cedar 

Pass, Warner Mountains (41°33.8′N, 120°16.1′W; 1825 

m), 8 Aug 1965 (1♂; CNC). Mono: Mono Lake (38°01′N, 

119°0.6′W), 22 Jul 1911, 1949, J. M. Aldrich, A. L. Melander (3♂, 2♀; CNC, USNM). Monterey: Carmel-by-theSea (36°13.3′N, 125°55.4′W), 5 Sept 1920, A. H. 

Sturtevant (1♂; USNM); Kirk Creek (35°59.3′N, 

121°29.8′W), 12 Aug 1969, R. Hocking (1♂, 1♀; CNC); 

Pacific Grove (36°37.1′N, 121°55′W), 8 May–27 Aug 

1920, 1921, A. H. Sturtevant (3♂, 6♀; USNM); Salinas 

(36°40.7′N, 121°39.3′W), 25 May 1952, P. H. Arnaud, Jr. 

(1♀; USNM). Napa: Bothe Napa Valley State Park 

(38°32.8′N, 122°32.1′W), 15 May 1980, K. S. Corwin 

(4♂, 2♀; CSCA); St. Helena (38°25.6′N, 122°19.6′W), 

3 Jun 1909, C. Fuchs (4♂, 13♀; ANSP). Nevada: Grass 

Valley (39°13.1′N, 121°03.7′W; 760 m), 23 Jun 1979, 

M. S. Wasbauer, F. Hillerman (5♂, 2♀; CSCA). Orange: 
7 8 • smithsonian contributions to zoology

Corona del Mar (33°35.9′N, 117°52.4′W), 25 Mar–28 

Dec 1944, 1946, A. L. Melander (2♀; USNM); Crystal 

Cove (33°34.8′N, 117°50.7′W), 6 Apr 2005, D. Mathis, 

W. N. Mathis (1♀; USNM); Knotts Ranch (33°50.6′N, 

118°33.4′W), 11 Apr 1956, A. L. Melander (1♂; USNM); 

Placentia (33°52.5′N, 117°52.1′W), 17 Jul 1964, C. Johnson (2♂; CSCA); San Clemente (33°25.6′N, 117°36.7′W), 

26 Mar–5 Jun 1945, 1946, A. L. Melander (2♂, 1♀; 

USNM); Santa Ana Canyon (33°51.4′N, 117°49.1′W), 29 

Mar 1950, A. L. Melander (1♂; USNM). Placer: Rocklin 

(6.5 km S; 38°47.3′N, 121°14.1′W; Malaise trap), 2–4 Jun 

1980, P. Adams, M. S. Wasbauer (5♂, 7♀; CSCA). Riverside: Andreas (33°45.5′N, 116°37.1′W), 1 April 1945, 

A. L. Melander (3♂, 1♀; USNM), 4 Apr 1955, W. R. 

Richards (2♀; USNM); Andreas Canyon (33°45.7′N, 

116°32.2′W), 20–27 Oct 1934, 1951, A. L. Melander, 

A. H. Sturtevant (2♀; USNM); Blythe (33°36.6′N, 

114°35.8′W), 24 Apr–1 May 1955, W. R. Richards (4♂, 

5♀; CNC); Coachella (33°40.8′N, 116°10.4′W), 27 Oct 

1930 (1♂; USNM); Desert Center (33°42.8′N, 

115°24.1′W), 2 May 1955, W. R. M. Mason (1♀; CNC); 

Fan Hill Canyon (16 km NE Thousand Palms; 33°53.1′N, 

116°15.9′W), 6 Apr 1955, W. R. M. Mason (2♂; CNC); 

Gavilan Hills (33°47.1′N, 117°22.2′W), 11 Apr 1954, 

A. L. Melander (1♀; USNM); Indio (33°43.2′N, 

116°13′W), 26 Apr–13 Dec 1944, 1949, A. L. Melander, 

R. E. Ryckman (1♂, 5♀; USNM); Indio (33°43.2′N, 

116°13′W), 7–21 Mar 1955, W. R. M. Mason, W. R. 

Richards (3♂, 2♀; CNC); Lake Elsinore (33°39.6′N, 

116°21.2′W), 25 May 1944, A. L. Melander (1♀; USNM); 

La Quinta (33°39.8′N, 116°18.6′W), 18 Nov 1952, A. L. 

Melander (1♂; USNM); Mg. Spring Canyon (near Indio; 

33°43.2′N, 116°13′W), 5 Apr 1945, A. L. Melander (1♀; 

USNM); Morongo Valley (33°57.6′N, 116°31.5′W), 19 

April 1944, A. L. Melander (1♂; USNM); Palm Springs, 

Palm Canyon (33°49.8′N, 116°32.7′W), 15 Mar 1955, W. 

R. Richards (1♀; CNC); Palm Springs (33°49.8′N, 

116°32.7′W), 2 Apr–29 Dec 1945, 1952, 1953, 1955, 

P. H. Arnaud, Jr., W. R. M. Mason, A. L. Melander (3♂, 

9♀; CNC, USNM (2♀; collected on 2 Apr 1945, A. L. 

Melander were part of the syntype series of T. tumida); 

Rancho Mirage (33°44.4′N, 116°24.8′W), 6 Apr 1955, 

W. R. M. Mason (18♂, 24♀; CNC); Riverside (33°58.8′N, 

117°22.4′W; ex. oats), 19 Mar 2002, E. Drake (3♂, 4♀; 

CSCA); Riverside (33°58.8′N, 117°22.4′W), 1 Feb–25 

May 1935, 1942, 1944, 1950, A. L. Melander (4♂, 3♀; 

USNM); Temecula (33°29.6′N, 117°08.9′W), 7 Jun 1945, 

A. L. Melander (2♀; USNM); Thermal (33°38.4′N, 

116°08.4′W), 14 Mar 1955, W. R. Richards (1♂; CNC); 

Thousand Palms (33°48.7′N, 116°22.6′W), 18 Mar–6 Jun 

1955, W. R. M. Mason, W. R. Richards (12♂, 25♀; CNC); 

Thousand Palms, Willis Palms Oasis (33°48.7′N, 

116°22.6′W), 8 Mar–5 Apr 1955, W. R. Richards (2♂, 

4♀; CNC); University of California, Riverside (33°58.5′N, 

117°19.7′W; Malaise), 7–21 Jun 1981, 1983, E. M. Fisher, 

D. Yu (8♀; CSCA, DEBU). Sacramento: Horticultural 

Commission (3♂, 3♀; CSCA); Andrus Island (38°09.5′N, 

121°35.9′W), 31 Mar 1931 (3♀; CSCA); Carmichael 

(38°37′N, 121°19.7′W), 22–26 Apr 1931, 22 Jun 1931, 

E. Gammon (1♂, 5♀; CSCA); Hood (28°22.1′N, 

121°31′W), 16 Apr 1931 (1♂, 1♀; CSCA); Courtland 

(38°19.9′N, 121°34.1′W; ex. alfalfa mustard), 4 May 

1932, S. Lockwood (3♂, 1♀; CSCA); Folsom (8 km N; 

38°40.7′N, 121°10.6′W), 16 Apr 1961, W. E. Simonds 

(1♂; CSCA); Hood (38°22.1′N, 121°31′W), 15 Apr 1931 

(1♂, 3♀; CSCA); Orangevale (38°40.7′N, 121°13.5′W), 

24 May 1930, H. H. Keifer (3♂, 1♀; CSCA); Rio Linda 

(38°41.5′N, 121°26.9′W), 15 May 1930, A. C. Browne 

(3♂, 17♀; CSCA); Sacramento (38°35.1′N, 121°30.3′W), 

30 Mar–12 Jul 1917, 1931, 1960, 1962, 1976, J. M. Aldrich, H. H. Keifer, I. Savage, W. E. Simonds, M. S. Wasbauer (23♂, 23♀; CSCA, USNM); Sacramento River 

Levee (38°36.3′N, 121°33.3′W), 24 Mar–15 May 1966, 

1970, F. Andrews, M. S. Wasbauer (1♂, 2♀; CSCA). San 

Bernardino: Baldwin Lake E, Hilltop on Rose Mine Road 

(34°15.2′N, 116°44′W; 2142 m), 26 May 2003, J. Skevington (1♂; CSCA); Barton Flats (34°10.4′N, 116°51.8′W; 

Ceanothus), 20–22 Jun 1945, 1948, A. L. Melander (2♀; 

USNM); Barton Flats, South Fork Camp (34°10.4′N, 

116°51.8′W), 3 Sep 1944. A. L. Melander (1♂; USNM); 

Big Bear Lake (34°14.6′N, 116°54.7′W), 13 May–6 Jul 

1942, 1955, A. L. Melander, W. R. Richards (2♂, 2♀; 

CNC, USNM); Crestline (34°14.5′N, 117°17.1′W), 4 June 

1947, A. L. Melander (1♂; USNM); Daggett (34°51.8′N, 

116°53.3′W), 14 Apr 1955, W. R. M. Mason (1♀; CNC); 

Helendale (34°44.6′N, 117°19.5′W), 18 May 1955, 

W. R. M. Mason, W. R. Richards (3♂, 1♀; CNC); Loma 

Linda (34°02.9′N, 117°15.7′W), 25 Apr 1949, R. E. Ryckman (1♀; USNM); Lytle Creek (34°15.5′N, 117°30′W), 

10 May 1953, A. L. Melander (1♂, 1♀; USNM); Mountain Home (34°06′N, 117°W), 7 July 1945, 29 Sep 1954, 

A. L. Melander (3♂, 1♀; USNM); New York Mountains 

(Keystone Canyon, 7 km S Ivanpah; 35°19.4′N, 

115°12.6′W; 1650 m), 6–7 Apr 1978, T. Eichling, M. S. 

Wasbauer (1♀; CSCA); Phelan (11.2 km E Baldy Mesa 

Road; 34°25.6′N, 117°34.3′W; pan traps), 15–31 May 

1982, J. T. Huber (2♂, 1♀; DEBU); South Fork Santa Ana 

River (34°10.3′N, 116°49.8′W), 18 Jul 1947, A. L. Melander (1♀; USNM); Tecopa (19 km ESE; 35°47.7′N, 

116°05.2′W), 13–14 Apr 1978, T. Eichlin, M. S. Wasbauer 
number 637 • 7 9

(4♀; CSCA); Twenty-nine Palms (32 km NE; 34°10′N, 

115°57.3′W), 3 Apr 1969, R. R. Pinger (1♂; USNM); Upland (34°05.8′N, 117°38.9′W; citronella bait trap), 16 

May 1950 (1♂; CSCA); Upper Santa Ana River (35°03.5′N, 

119°21.8′W), 13 May–26 Jun 1947, 1956, 1957, A. L. 

Melander (1♂, 2♀; USNM); Verdemont (34°11.6′N, 

117°22.1′W), 22 May 1945, A. L. Melander (1♂; USNM); 

Victorville (34°32.2′N, 117°17.5′W), 2–24 May 1953, 

1955, G. A. Marsh, W. R. M. Mason, R. Shuster, W. R. 

Richards (5♂, 7♀; CNC, USNM). San Diego: AnzaBorrego State Park (2.4 km SE of Scissors Crossing; 

33°05.5′N, 116°27.3′W; 685 m), 18 Apr 2003, S. D. 

Gaimari, E. M. Fisher (7♂, 5♀; CSCA); Borrego Springs 

(33°15.4′N, 116°22.5′W), 30 Apr 1960, M. S. Wasbauer 

(1♂; CSCA); Borrego (north end Clark Lake; 33°20.3′N, 

116°16.7′W; Malaise trap), 23 Mar 1978, P. Adams, 

J. Slansky, M. S. Wasbauer (1♂, 1♀; CSCA); Borrego State 

Park, Clark Dry Lake (33°13.7′N, 116°15.7′W), 1 Apr 

1977, J. Slansky, M. S. Wasbauer (2♀; CSCA); Borrego 

(north end Clark Lake; 33°20.3′N, 116°16.7′W), 23 Mar 

1978, P. Adams, J. Slansky, M. S. Wasbauer (7♀; CSCA); 

Borrego, Palm Canyon (33°13.2′N, 116°20.1′W), 3 May 

1945, A. L. Melander (2♂; USNM); El Cajon (32°47.7′N, 

116°54.8′W; on pupae Harrisina brillians), “winter” 

1946–47 (1♀; USNM); Imperial Beach (32°35.6′N, 

117°07.4′W), 5 Apr 2005, D. Mathis, W. N. Mathis (1♀; 

USNM); La Jolla (32°50.8′N, 117°16.5′W), 28 Mar 1946, 

A. L. Melander (1♂; USNM); Lake Henshaw (33°13.9′N, 

116°45.6′W), 7 May 1945, A. L. Melander (1♀; USNM); 

Oak Grove (33°23.1′N, 116°47.4′W), 8 May 1945, A. L. 

Melander (6♂, 2♀; USNM); Palomar Mountain 

(33°19.4′N, 116°52.7′W), 14 Jun 1948, A. L. Melander 

(1♀; USNM); Pauma Valley (33°18.2′N, 116°58.9′W; ex. 

orange), 29 Aug 1959, C. Johnson (1♀; CSCA); San Diego 

(32°42.9′N, 117°09.4′W), 28 Jun 1917, J. M. Aldrich 

(1♂, 2♀; USNM). San Francisco: San Francisco, Lake 

Merced (37°43.3′N, 122°29.8′W), 3 May 1968, P. H. Arnaud, Jr. (1♂; USNM); San Francisco (37°46.5′N, 

122°25.4′W), 29 Apr–8 Aug 1929, 1954, P. H. Arnaud, 

Jr., H. H. Keifer (1♂, 2♀; USNM). San Luis Obispo: 

Morro Bay (35°20.3′N, 120°51.1′W), 16 Jun–27 Jul 1940, 

1957, A. L. Melander (1♂, 3♀; USNM). San Mateo: 

Atherton (37°27.7′N, 122°11.9′W), 7 May 1953, 14 Jul 

1951, P. H. Arnaud, Jr. (9♂, 6♀; USNM); Redwood City 

(37°29.1′N, 122°14.2′W), 26 Jun 1946, 27 Apr 1947, 2 

May 1953, 23 May 1954, 15 May–1 Jun 1960, P. H. Arnaud, Jr. (7♂, 5♀; USNM). Santa Barbara: Santa Cruz Island, Field Station (33°59.8′N, 119°43.6′W; pan traps), 

19–22 Mar 1982, J. T. Huber (1♂; DEBU); Santa Cruz 

Island, between head of Alamos Canyon and Centinela 

(34°01′N, 119°48.5′W; sweeps of low vegetation near 

pines), 21 Mar 1982, J. T. Huber (8♂, 5♀; DEBU); Santa 

Cruz Island, Christy Beach and Canyon (34°01.5′N, 

119°52.4′W; pan traps), 22 Mar 1982, J. T. Huber (36♂, 

11♀; DEBU); Santa Cruz Island, Water Canyon 

(35°00.2′N, 119°45.8′W), 17 Jun 1967, R. O. Shuster 

(1♀; CSCA); Santa Maria (35°55.3′N, 120°06.1′W), 3 Jun 

1950 (1♂, 1♀; CSCA). Santa Clara: Alviso (37°25.6′N, 

121°58.5′W), 13 May 1921, A. H. Sturtevant (1♂; 

USNM); Palo Alto (37°26.7′N, 122°09.6′W), 3 Apr–26 

Sep 1921, A. H. Sturtevant (6♂, 6♀; USNM); Stanford 

University (37°25.6′N, 122°10.2′W), 12 May 1952, 6 

May 1953, 1–29 Apr 1954, 23 Apr–2 May 1961, P. H. 

Arnaud, Jr. (2♂, 7♀; USNM). Santa Cruz: Felton 

(37°02.1′N, 122°04.4′W), 17–18 May 1947, P. H. Arnaud, 

Jr. (3♀; USNM); Watsonville (36°54.6′N, 121°45.4′W), 9 

May 1921, A. H. Sturtevant (1♂, 3♀; USNM). Shasta: Fall 

River Mills (10 km W; 41°0.3′N, 121°27′W), 5 Apr 1959, 

M. T. James (1♂; WSU); Redding (40°34.2′N, 122°22′W), 

1 Jun 1980, T. R. Haig (1♂; CSCA). Siskyou: Granada 

(41°34.7′N, 122°04.2′W; ex. alfalfa), 25 May 1930, M. L. 

Jones (1♀; CSCA); McBride Springs Campground 

(41°21.2′N, 122°17.1′W; 1463–1585 m), Mount Shasta, 

20–22 Jul 1965 (4♀; CNC); Shadow Creek (11.25 km W 

of Cecilville; 41°08.4′N, 123°08′W), 5 Sep 1968, G. M. 

Buxton, A. B. Gurney (2♀; USNM). Solano: Fairfield 

(38°15′N, 122°02.6′W), 12 Apr 1959, P. H. Arnaud, Jr. 

(2♂; USNM); Gates Canyon (38°22.9′N, 122°02.2′W; 

250–500 m), 14–20 Jun 1994, S. D. Gaimari (1♂; CSCA); 

Lake Berryessa (1.4 km SW Monticello Dam; 38°30.20′N, 

122°06.39′W), 4 Jun 2002, S. D. Gaimari (6♂, 2♀; CSCA); 

Stebbins Cold Canyon Reserve (38°31′N, 122°06′W; 100 

m), 20 May 2003, S. D. Gaimari (1♀; CSCA); Stebbins 

Cold Canyon Reserve, Hilltop along Blue Ridge 

(38°33.3′N, 122°06.3′W; 445 m), 20 May 2003, J. Skevington (1♀; CSCA). Sonoma: Bodega Marine Station 

(38°18.4′N, 123°04.1′W), 3 May 1968, D. D. Munroe 

(2♂, 1♀; CNC); Cotati (38°19.9′N, 122°41.5′W; ex. purple vetch), 13 Jun 1939, S. Lockwood (1♂, 2♀; CSCA); 

Mesa Grande (38°28.1′N, 123°01.9′W), May 1908, J. P. 

Baumberger (2♂, ANSP). Trinity: Shasta Spring 

(40°44.1′N, 122°54.7′W), Jul 1915, A. L. Melander (1♀; 

USNM). Tulare: Ash Mountain (36°29.9′N, 118°50′W; 1 

km SE, Sequoia National Park Headquarters (flume debris 

trap), 25 Apr 1984, R. D. Haines (1♂; CSCA). Ventura: 

Wheeler Canyon, Maricopa Road (34°20.1′N, 

119°08.4′W), 1 Jun 1958, W. E. Simonds (4♀; CSCA). 

Yolo: Davis (38°32.7′N, 121°44.4′W), 27 Apr 2005, K. A. 

Williams (1♂; CSCA); Woodland (38°40.7′N, 121°46.4′W; 

ex. alfalfa), 17 Jun 1930, A. C. Browne (1♀; CSCA).
8 0 • smithsonian contributions to zoology

Colorado. El Paso: Manitou (38°51.6′N, 104°55′W), 

18 Jun 1940, A. L. Melander (1♂; USNM). Larimer:

Loveland (40°23.9′N, 105°04.5′W), Aug 1955, H. Stalker 

(1♀; USNM). Rio Grande: South Fork (37°40.2′N, 

106°38.4′W; 2440 m), 20 Jun 1972 (1♂, 1♀; USNM).

Idaho. Ada: Boise (43°36.8′N, 116°12.2′W; sawmill 

window), no date given, J. M. Aldrich (1♂, 3♀, USNM). 

Bonner: Priest Lake (48°29.4′N, 116°54.2′W), 3 Sept 

1919, A. L. Melander (1♀; USNM). Elmore: Glenns Ferry 

(42°57.3′N, 115°18.1′W; Filipes rosea), 14 Jun 1927 (2♀; 

USNM). Gooding: Gooding (1.6 km NE; Wood River; 

42°56.3′N, 114°42.8′W), 6–7 Jul 1980, M. S. Wasbauer 

(1♀; CSCA); Wendell (42°46.4′N, 114°42.3′W), 22 May 

1931, D. E. Fox (1♀; USNM). Jerome: Jerome (42°43.5′N, 

114°31.1′W), 10 Jun 1930 (1♀; USNM). Kootenai: 

Fourth of July Canyon (47°33.6′N, 116°26.3′W), 27 

Jul 1918, A. L. Melander (1♂; USNM); Coeur d′Alene 

(47°40.7′N, 116°46.8′W), 27 Jul–24 Aug 1916, 1944, 

A. L. Melander (2♀; USNM); Harrison (16 km NE; 

47°28′N, 116°46′W), 24–28 Jul 1977, W. J. Turner (1♀; 

WSU). Latah: Indian Hills area of Moscow (46°44.2′N, 

117°01′W), 3 Jul 1993, R. S. Zack (1♀; WSU); Moscow

Mountain (46°48.2′N, 116°52.1′W), 8 Jun–7 Jul 1912, 

1915, 1918, 1919, 1921, 1948, M. T. James, A. L. Melander (11♂, 7♀; USNM, WSU); Moscow (46°44′N, 

117°01′W; on parsnip flowers), 1 Jun–2 Jul 1912, 1916, 

1970, J. M. Aldrich, W. F. Barr (9♂,83♀; DEBU, USNM); 

Potlatch (46°55.3′N, 116°53.9′W), 4 Sept 1912, J. M. Aldrich (2♂, 2♀; USNM); St. Joseph National Forest, Giant 

White Pine Campground (47°0.6′N, 116°40.7′W), 16 

Aug 1970, W. B. Garnett (1♂; WSU); Viola (46°50.3′N, 

117°01.5′W), 26 Jun 1912, J. M. Aldrich (1♂; USNM); 

Yale (46°51.7′N, 116°41.8′W), 10 Sept 1912, J. M. Aldrich 

(1 ♀; USNM). Nez Perce: Craig Mountain (46°04.6′N, 

116°51.1′W), 8 Jun 1918, A. L. Melander (1♂; USNM); 

Lewiston (46°27.8′N, 116°58.6′W), 21–22 Jun 1948, 

1954, R. R. Sanders, A. H. Sturtevant (7♂, 28♀; USNM); 

Lewiston (13 km NW, top of grade; 46°28′N, 116°59′W), 

30 Jun 1975, W. J. Turner (1♂; WSU). Washington:

Weiser (Route 95; 44°15.1′N, 116°58.2′W), 3 May 1990, 

R. S. Zack (1♀; USNM).

Maryland. Montgomery: Plummers Island (38°58.2′N, 

77°10.6′W), 2 Jun 1912, W. L. McAtee (1♀; USNM). 

Prince George’s: Laurel (39°06.1′N, 76°54′W), 16–24 

May 1967, D. R. Smith (2♀; USNM).

Montana. Glacier: Glacier Park, Two Medicine Lake 

(48°28.6′N, 113°23.3′W), 3 Aug 1935, A. L. Melander 

(1♂; USNM). Sanders: Perma (47°21.8′N, 114°35.1′W), 25 

Aug 1918, A. L. Melander (1♂; USNM); Thompson Falls 

(47°35.7′N, 115°20.8′W), 25 Aug 1918, A. L. Melander 

(1♂; USNM). Sheridan: Medicine Lake (48°30.1′N, 

104°30.3′W), 9 Jun 1969, W. W. Wirth (2♀; USNM).

Nevada. Clark: Las Vegas (36°10.5′N, 115°08.2′W), 

16 Apr 1932, E. W. Davis (1♀; USNM); Overton 

(36°32.6′N, 114°26.8′W), 15 Oct 1929, D. E. Fox (1♀; 

USNM). Ormsby: Clear Creek Campground (39°06.9′N, 

119°53.4′W; 1980 m), 27 Jul 1968, D. D. Munroe (1♀; 

CNC). Washoe: Indian School, Pyramid Lake (39°49.9′N, 

119°21.5′W), Jul 1911, J. M. Aldrich (1♀; USNM); Reno 

(39°31.8′N, 119°48.8′W), 28 Aug 1915, 12 Jul 1952, 

H. G. Dyar (2♂; USNM).

New Mexico. Bernalillo: Tijeras (10.2 km S; 35°05′N, 

106°22.5′W; 730 m), 23–26 Aug 1975, S. Peck (1♂; 

DEBU). Catron: Gila National Forest, riparian zone, 

Whitewater Creek Canyon (33°18.9′N, 108°53.2′W), 

30 May 1991, B. J. Sinclair (1♀; CNC); Luna (10 km S; 

33°48.9′N, 108°57.3′W; 2440 m; pond, pine forest, Malaise trap), 9–14 Jul 1979, S. Peck, J. Peck (1♀; DEBU); 

Luna (13 km SE; 33°48.9′N, 108°57′W; 2690 m), 9–14 

Jul 1979, S. Peck, J. Peck (3♂, 1♀; DEBU); San Francisco 

River (8 km W Luna; 35°05′N, 106°23′W; 2255 m), 9–14 

Jul 1979, S. Peck, J. Peck (3♂, 7♀; DEBU). Grant: Cherry 

Creek, Pinos Altos (32°51.8′N, 108°13.3′W), 22 Jun 1953, 

W. W. Wirth (1♂, 1♀; USNM); Gila National Forest, near 

Lake Roberts (33°02′N, 108°10′W; dry stream bed), 28 

May–5 Jun 1991, J. E. Swann (9♂, 5♀; DEBU); Gila National Forest, near Lake Roberts (33°02′N, 108°10′W), 

29 May 1991, J. E. Swann (3♂, 1♀; DEBU). Santa Fe:

Glorieta Baldy (35°39.1′N, 105°48′W; 3290–3600 m), 19 

Jun–4 Jul 1979, S. Peck, J. Peck (3♀; DEBU); Santa Fe 

(22.5 km NE; 35°42′N, 105°57′W, 2925 m), 18 Jun–3 Jul 

1979, S. Peck, J. Peck (1♀; DEBU). Socorro: Magdalena 

Mountains, Water Canyon (24 km W Socorro; 34°02.9′N, 

107°11.1′W; 2200 m), 2 Oct 1982, V. Hornoff (2♀; CNC); 

Water Canyon (32 km W Socorro; 33°51.4′N, 107°25′W; 

2135 m), 28 Jun–7 Jul 1979, S. Peck, J. Peck (3♂, 7♀; 

DEBU); South Baldy Peak (33°59.5′N, 107°11.3′W; 3170 

m), 28 Jun–7 Jul 1979, S. Peck, J. Peck (1♂, 4♀; DEBU). 

Torrance: Manzano Red Canyon Camp (34°36.1′N, 

106°21.8′W; 2990 m), 17–30 Jun 1979, S. Peck, J. Peck 

(1♂, 3♀; DEBU).

Oregon. Baker: Cougar Creek (60 km SE Union; 

44°56.9′N, 117°24.9′W; 1244 m), 28 Jun 1977, E. J. 

Davis (1♀; WSU); Wetmore Campground (44°31.5′N, 

118°18.1′W; Malaise trap), 29 Jun–5 Jul 1965 (2♂; 

CNC). Benton: Corvallis (44°33.9′N, 123°15.7′W), 

no date given, R. W. Lauderdale (1♀; USNM); Corvallis (44°33.9′N, 123°15.7′W), 2–9 Jul 1972, G. C. 

Steyskal (3♂, 4♀,USNM); Corvallis (44°33.9′N, 

123°15.7′W), 18 May 1972, Wayne N. Mathis (2♀; 
number 637 • 8 1

DEBU); Corvallis (44°33.9′N, 123°15.7′W), 10 Jul 1935, 

E. Gray (1♂; DEBU); Finley National Wildlife Refuge 

(44°24.6′N, 123°19.5′W), 3 Jul 1972, G. C. Steyskal (1♂; 

USNM). Coos: 7-Devils State Recreation Site (43°14.2′N, 

124°23.4′W; beach), 30 Jul 2005, D. Mathis, W. N. Mathis 

(3♂; USNM). Curry: Pistol River (4.8 km SE; 42°16.6′N, 

124°23.7′W), 28 Jun 1972, G. C. Steyskal (1♀; USNM); 

Gold Beach (12.9 km N; 42°24.5′N, 124°25.3′W), 29 Jun 

1972, G. C. Steyskal (5♂; USNM). Douglas: Elkton (13 

km W; 43°38.3′N, 123°34.1′W), 16 Jun 1971, G. C. Steyskal (1♂,3♀; USNM). Harney: Pike Creek (42°34.5′N, 

118°31.7′W; 1320 m), 7 Aug 2005, D. Mathis, W. N. 

Mathis (1♂; USNM). Hood River: Hood River Rapids 

(45°42.9′N, 121°30.7′W), 29 Jul 1921, A. L. Melander 

(1♀; USNM); Mount Hood (45°32.3′N, 121°34.1′W; 915 

m), 29 Jul 1921 (2♂; USNM). Klamath: Klamath Falls 

(42°13.5′N, 121°46.9′W), 22 Jun 1971, G. C. Steyskal 

(3♂, 5♀; USNM). Lane: Florence (3.2 km S; 43°58.9′N, 

124°06′W), 7 Jul 1971, G. C. Steyskal (4♂; USNM); Willamette National Forest (44°15′N, 122°0.1′W; in canopy of 

Pseudotsuga menziesii), 1976 (no other date given), Voegtlin, Christy (2♂, 1♀; USNM). Lincoln: Waldport (4 km 

N; 44°26′N, 120°04.1′W), 1 Jun 1971, P. W. Oman (1♂, 

1♀; DEBU). Marion: Aurora (45°13.9′N, 122°45.4′W), 

20 Jun 1925, A. L. Melander (2♀; USNM). Morrow: 

Heppner (Willow Creek; 45°21.2′N, 119°33.5′W), 18 Jun 

1991, R. S. Zack (2♂, 7♀; WSU). Polk: Dallas (44°55.2′N, 

123°19′W), 22 Aug 1951 (1♂, 2♀, USNM). Umatilla: 

McNary, McNary Dam Wildlife Area (453°56.4′N, 

119°17.9′W), 11 Aug 1993, R. S. Zack (7♂, 17♀; WSU); 

Umapine (45°58.6′N, 118°29.8′W), 21 Jun 1921, A. L. 

Melander (1♂, 2♀; USNM). Union: Jordan Creek (SSW 

La Grande; 45°18.6′N, 118°16.7′W; 1475 m), 15–21 Jun 

1975, E. J. Davis (1♀; WSU). Wallowa: Troy (45°56.8′N, 

117°27.1′W), 10 Aug 1926, A. L. Melander (1♀; USNM); 

Wallowa Lake State Park (9.6 km S Enterprise; 45°16.1′N, 

117°12.7′W; Malaise trap with dry ice; 3000′–4000′ [915–

1220 m]), W. J. Turner (6♂, 1♀; WSU).

Texas. Brewster: Big Bend National Park, Dugout 

Wells (29°16.3′N, 103°08.1′W; 915 m), 13 May 1959, 

J. F. McAlpine (2♂; CNC).

Utah. Cache: Logan Canyon (41°44.4′N, 

111°47.6′W), 2 Jul–19 Aug 1970, 1976, G. F. Knowlton 

(1♂, 2♀; USNM, WSU). Duchesne: Uinta Mountains, 

Rocky Sea Pass (40°41.7′N, 110°46.2′W; 3434 m), 30 

Jul–12 Aug 1979, S. Peck, J. Peck (1♀; DEBU). Grand: 

15 km N Green River (39°7′N, 110°6.6′W), 29 May 

2007, D. Mathis, W. N. Mathis (1♀: USNM). Kane: Sand 

Spring-Coral Pink Sand Dunes (37°4.6′N, 112°39.9′W), 

16 May 2001, D. Mathis and W. N. Mathis (4♂; USNM). 

Utah: Goshen Hot Springs (39°57.8′N, 111°51.2′W), 18 

Apr 2003, W. N. Mathis, T. Zatwarnicki (1♂; USNM).

Washington. Adams: Lake Paha (46°58.1′N, 

118°34.4′W), 20 Jul 1920, R. C. Shannon (1♂; USNM); 

Lind (46°58.3′N, 118°36.9′W), 5 Jun 1990, R. S. Zack 

(3♂, 8♀; WSU); Lind (NNE; Washington State University 

Experimental Station; 46°58.3′N, 118°36.9′W), 5 Jun 

1990, R. S. Zack (8♀; WSU); Ritzville (47°07.7′N, 

118°22.8′W), 15 Jun–8 Jul 1920, 1936, P. W. Oman, R. C. 

Shannon (1♂, 1♀; USNM); Sand Hills Park (19.5 km W 

Washtucna; 46°46.8′N, 118°31.6′W), 13 Jun 1989, R. S. 

Zack (1♂, 3♀; WSU). Asotin: Asotin Creek (46°20.6′N, 

117°03.2′W), 11 May 1924, A. L. Melander (1♀; USNM); 

Cloverland (13 km S; 46°15′N, 117°15′W; Blue Mountains), 30 Jun 1956, M. Coffey (1♂, 2♀; WSU); Fields 

Spring State Park (46°04.9′N, 117°10.2′W), 31 Jul 1971, 

W. J. Turner (1♀; WSU); Grande Ronde (46°04.8′N, 

116°58.8′W), 10 Jun 1980, G. C. Steyskal (2♂, 2♀; 

USNM); Grande Ronde (27.4 km S Anatone; 46°04.8′N, 

116°58.8′W; 595 m), 15 Jun 1977, W. J. Turner (1♂, 1♀; 

WSU); Silcott (46°24.9′N, 117°11.8′W), 14 Jun 1980, 

G. C. Steyskal (4♂, 4♀; USNM); Snake River, opposite 

Clarkston (46°25′N, 117°02.7′W), 3 May 1925, A. L. 

Melander (1♂; USNM). Benton: Kennewick (46°12.7′N, 

119°08.2′W), 20 May–7 Jun 1916, 1921, A. L. Melander 

(4♂, 6♀; USNM); Prosser (46°12.4′N, 119°48′W), 24 Apr 

1951, E. Klotermeyer (1♂; WSU); Richland (46°17.3′N, 

119°17.5′W), 6 Jun 1974, N. E. Woodley (2♀; WSU); 

West Richland (46°17.1′N, 119°17.2′W), 4 Jun 1975, N. 

E. Woodley (2♀; WSU). Chelan: Cashmere (47°31.3′N, 

120°28.2′W), 29 May 1917, A. L. Melander (1♀; USNM); 

Telma (47°50.6′N, 120°48.9′W; Lake Wenatchee), 18 Jul 

1972, W. B. Garnett (1♀; WSU); Wanatchee (15 km SE; 

Squilchuck State Park 47°18.5′N, 120°22.4′W), 17 Jun 

1973, W. J. Turner (1♂; WSU); Winesap (47°45.6′N, 

120°12′W), 11 Jun 1942, R. D. Shenefelt (1♂; WSU). 

Clallam: Olympia National Park, Elwha River (48°09′N, 

123°33.6′W), 6 Jul 1968, W. W. Wirth (1♀; USNM); Port 

Angeles (48°07.1′N, 123°25.8′W), 12 Jul 1942, R. D. 

Shenefelt (1♂; WSU). Clark: Vancouver (45°38.1′N, 

122°36′W), 2 Jun–10 Jul 1970 (4♂, 2♀; WSU). Cowlitz: 

Woodland (45°54.3′N, 122°48.6′W), 23 May 1910, A. L. 

Melander (1♀; USNM). Ferry: Republic (14.5 km S; Sanpoil River Hwy 21; 47°56.9′N, 118°40.8′W; Malaise trap 

with dry ice; 650 m), 23 Jul 1975, W. J. Turner (1♂, 5♀; 

WSU); Republic (15 km S, 10-Mile Campground; 

48°35.1′N, 118°09′W; Malaise trap with dry ice), 7 Jul 

1972, W. J. Turner, W. B. Garnett (2♀; WSU); Republic 

(52 km E, Colville National Park, Sherman Creek; 

48°35.1′N, 118°08.46′W; Malaise trap with dry ice), 
8 2 • smithsonian contributions to zoology

27–28 Jul 1973, W. J. Turner, D. Corredor (1♀; WSU). 

Franklin: Eltopia (16 km W; 46°27.5′N, 119°02′W), 29 

May 1957, E. F. Dailey (12♀; WSU); Eltopia (48 km N; 

46°50′N, 119°02′W), 29 May 1957, E. F. Dailey (12♂, 

16♀; WSU); Port of Pasco (46°12.6′N, 119°02.9′W), 

6 Jun 2006, D. Mathis, W.N. Mathis (1♀; USNM). Garfield: Central Ferry (46°37.6′N, 117°49.1′W), 7 Jun 1970 

(2♀; WSU); Lower Granite Dam (16 km W; 46°39.6′N, 

117°25.9′W; sand dunes), 12 Jul 1993, R. S. Hanley (1♀; 

WSU). Grant: Burke (10.5 km N, Highway 7; 47°06′N, 

119°52.5′W), 30 Apr (1♀; WSU); Columbia Natural 

Wildlife Refuge (5 km S O’Sullivan Dam, Crab Creek; 

47°01.2′N, 119°19.3′W), 20 Jun 1975, N. E. Woodley 

(1♀; WSU); Coulee City (47°36.7′N, 119°17.5′W), 3 Sep 

1920, A. L. Melander (1♀; USNM); O′Sullivan Dam 

(46°59′N, 119°17.5′W), 23 May 1954, M. T. James (4♀; 

USNM, WSU); Trinidad (10 km NW; 47°14′N, 120°01′W), 

30 May 1957, E. F. Dailey (1♂, 5♀; WSU); Winchester 

(47°14.9′N, 119°43.2′W), 5 Jul 1950, D. Malcolm (1♂; 

WSU). Grays Harbor: Westport (46°53.4′N, 124°06.2′W), 

28 Jun 1988, D. Mathis, W. N. Mathis (4♂, 2♀; USNM). 

Jefferson: Brinnon (47°40.8′N, 122°53.9′W; Duckabush 

Creek), 3 Aug 1972, W. J. Turner (1♀; WSU); Fort Worden, near Port Townsend (48°07′N, 122°45.6′W), 15 Jun 

1971, D. N. Ferro, J. A. Novak (7♂, 10♀; WSU); Hoh 

(47°45′N, 124°24.6′W), 4 Aug 1972, W. J. Turner, W. B. 

Garnett (1♀; WSU); Port Townsend (48°07′N, 

122°45.6′W), 16 Jun 1971, W. Wiebers (1♂, 6♀; WSU); 

Quilcene (47°49.3′N, 122°52.6′W), 16 Aug 1910, A. L. 

Melander (2♀; USNM). Kittitas: Cle Elum (47°11.7′N, 

120°56.3′W), 17 Jul 1972, W. B. Garnett (1♂, 1♀; USNM); 

Ellensburg (11 km S; 46°58′N, 120°32′W), 18 Jul 1957, 

E. F. Dailey (1♂; WSU); Hudson Creek (46°56′N, 

120°50.5′W), 29 Jun 1924, A. L. Melander (1♂; USNM); 

Liberty (47°15.2N, 120°39.9′W; Williams Creek), 17 Jun 

1972, W. B. Garnett, W. J. Turner (1♂, 4♀; WSU); Swauk 

Meadow (47°19.5N, 120°34.8′W), 17 Jun 1972, W. B. 

Garnett, W. J. Turner (1♀; WSU). Klickitat: Bickleton 

(45°59.9′N, 120°18′W), 26 Jun 1917, A. L. Melander 

(1♀; USNM); Goldendale (45°49.2′N, 120°49.3′W), 23 

Jul 1921, A. L. Melander (9♂, 1♀; USNM); Goldendale 

(27 km ENE; 45°50′N, 120°48′W), 17 Apr 1991, R. S. 

Zack (1♀; WSU); Husum (45°48′N, 121°29.2′W), 28 Jun 

1917, A. L. Melander (2♀; USNM); Klickitat River, Glenwood Road (45°41.8′N, 121°17.5′W), 23 Jul 1921, A. L. 

Melander (1♂; USNM). Mason: Shelton, Walkers Park 

(47°17′N, 122°55.5′W), 21 Jul 1917, A. L. Melander (1♀; 

USNM). Okanogan: Carlton (8 km SE; 48°14.9′N, 

120°07′W; Malaise trap with dry ice), 19 Jul 1972, W. J. 

Turner (1♂, 4♀; WSU); Conconully (14.5 km NW, Salmon 

Meadows; 48°39.3′N, 119°50.3′W; Malaise trap with dry 

ice, 1372 m), 23–26 Jul 1975, W. J. Turner (2♀; WSU); 

Little Goose Lake (11.5 km SE Okanogan; 48°16′N, 

119°29′W), 22 Jul 1983, R. D. Akre, R. S. Zack (1♀; 

WSU); Okanogan (48°21.2′N, 119°35′W), 20 May 1924, 

A. L. Melander (2♀; USNM); Omak (48°24.7′N, 

119°31.7′W), 19 May 1916, A. L. Melander (1♂; USNM); 

Oroville (48°56.4′N, 119°26.1′W), 1 May 1912, A. L. 

Melander (2♀; USNM); Sweat Creek Campground 

(48°40.9′N, 118°54.4′W), 7 Jul 1972, W. J. Turner (2♂; 

WSU); Twisp (6.5 km E; Route 20; 48°29.8′N, 120°07.3′W; 

Malaise trap CO2), 19 Jul 1972, W. J. Turner, W. B. Garnett (2♀; WSU); Okanogan National Park Highway 30, 

28 Jul 1973, W. J. Turner (2♀; WSU); Wauconda (8 km E; 

48°43.6′N, 118°58′W; Route 30), 7 Jul 1972, W. J. Turner 

(1♂, 2♀; WSU); Winthrop (22.5 km N, near Chewack 

Campground; 48°51.5′N, 120°01.5′W), 19 Jul 1972, 

W. B. Garnett, W. J. Turner (1♂, 4♀; WSU). Pacific: Fort 

Canby State Park (46°17.5′N, 124°04.3′W), 11–29 Jun 

1971, 1988, D. Mathis, W. N. Mathis, W. J. Turner (2♂, 

1♀; USNM, WSU); Francis (46°32.5′N, 123°30′W), 21 

Jun 1989, R. S. Zack (1♂; WSU); Seaview (upper beach; 

46°20′N, 124°03.3′W), 21 Jun 1989, R. S. Zack (3♂, 2♀; 

WSU). Pierce: Tacoma (47°15.2′N, 122°26.7′W), 29 Jul 

1917, A. L. Melander (1♂, 3♀; USNM); Tahoma Creek, 

Mount Rainer (46°44.2′N, 121°54.3′W), 25 Jul 1922, 

A. L. Melander (1♀; USNM). San Juan: Friday Harbor 

(48°32′N, 123°01′W), 11 Jul 1966, W. Baker (1♀; WSU). 

Skagit: Rockport State Park (12 km E Concrete; 48°29.3′N, 

121°36.9′W), 16–17 Jun 1971, J. A. Novak (1♂, 4♀; 

WSU). Spokane: Dartford (47°47.1′N, 117°25′W), 22 

Jun–22 Aug 1970, R. D. Gray (5♀; WSU); Mt. Spokane 

State Park, Burbling Creek on Day-Spokane Road 

(47°55.5′N, 117°07′W; 1143 m), 26 Jun 1978, W. J. 

Turner (1♂; WSU); Mica (47°33.4′N, 117°12.7′W), 14 Jul 

1918, A. L. Melander (1♂; USNM); Valleyford (47°31.2′N, 

117°16.2′W), 19 Jun 1919, A. L. Melander (1♂; USNM). 

Stevens: Chewelah (1.6 km W, Rt. 395; 48°16.6′N, 

117°42.9′W; Malaise trap with dry ice), 6 Jul 1972, W. B. 

Garnett, J. Turner (2♂, 4♀; WSU); Chewelah (11 km SE, 

Cottonwood Creek; 48°13.7′N, 117°42.4′W; Malaise trap 

with dry ice), 6 Jun 1972, W. B. Garnett, J. Turner (6♂, 

10♀; WSU); Colville (48°32.8′N, 117°54.3′W), 21 Jun 

1920, R. C. Shannon (10♂; WSU); Colville (6.5 km S, 

Route 395; Colville River; 48°34.4′N, 118°06.4′W; Malaise trap with dry ice), 6 Jul 1972, W. B. Garnett, W. J. 

Turner (2♂; WSU); Deer Lake (8 km NE; 48°06.8′N, 

117°35.4′W; Malaise trap with dry ice; 975 m), 11–13 Jul 

1975, W. J. Turner (1♂, 2♀; WSU); Deer Lake (3.2 km SE; 

48°06′N, 117°35′W; Malaise trap), 27–28 Jul 1973, W. J. 
number 637 • 8 3

Tuner, D. Corredor (3♀; WSU); Kettle Falls (48°36.7′N, 

118°03.4′W), 3 May 1912, A. L. Melander (1♀; USNM). 

Thurston: Puget (47°08.8′N, 122°47.6′W), 4 Jul 1925, 

A. L. Melander (1♀; USNM). Walla Walla: Burbank (6.2 

km S; 46°11′N, 119°01′W), 14 Apr 1973, W. J. Turner 

(2♂; WSU); Lowden (46°03.4′N, 118°35.1′W), 23 Jun 

1921, A. L. Melander (1♀; USNM); Touchet (5 km E; 

46°02.4′N, 118°40′W), 4 Jun 1957, E. F. Dailey (1♂; 

WSU); Walla Walla, Mill Creek (46°02.3′N, 118°28.7′W), 

2–6 Jul 1922, A. L. Melander (1♂, 4♀; USNM). Whatcom: Mt. Baker, Nooksack River (48°55.7′N, 122°19.3′W), 

11 Aug 1925, A. L. Melander (1♀; USNM); Silver Fir 

Campground (48°54.2′N, 121°42.1′W; dry ice Malaise 

trap), 8–11 Aug 1974, W. J. Turner (1♂; WSU). Whitman: 

Albion (46°47.6′N, 117°15′W), 12 Jul 1948, M. T. James 

(1♂; WSU); Almota (46°42.2′N, 117°28.2′W), 14 Jun 

1980, A. L. Melander, G. C. Steyskal (4♂, 7♀; USNM, 

WSU); “Big” Almota Canyon (46°42.1′N, 117°28′W; 

Malaise trap with dry ice), 25 Jul 1973, D. Corredor, 

S. Berkencamp (2♂, 5♀; WSU); Clarkston (46°27.5′N, 

117°06.1′W), 15 May–24 Jun 1912, 1924, 1949, J. M. 

Aldrich, C. C. Esselbaugh, A. L. Melander (6♂, 6♀; 

USNM, WSU); Colfax (8 km SE; 46°52′N, 117°29′W), 25 

May 1989, R. S. Zack (18♂; 4♀; WSU); Colton (46°34.1′N, 

117°07.7′W), 9 Jun 1948, C. C. Shelton (31♂, 60♀; WSU); 

Colton (16 km SW; Steptoe Canyon; 46°27.1′N, 

117°12.4′W; 275 m), 29 Jul–3 Aug 1974, 1975, W. J. 

Turner (3♂; 1♀; WSU); Colton (13 km SW, Steptoe Canyon; 46°27.1′N, 117°12.2′W; Malaise trap with dry ice), 

26 Jul 1973, D. Corredor (4♂, 6♀; WSU); Colton 

(46°34.1′N, 117°07.7′W; Virgin Prairie Population Study 

Project), 9 Jun 1948, C. C. Shelton (42♂, 57♀; WSU); Kamiak Butte (46°51.8′N, 117°10′W), 13 Jul 1912 (2♂; 

USNM); LaCrosse (5 km E; 46°48.9′N, 117°52.9′W), 13 

Jun 1989, R. S. Zack (8♂, 29♀; WSU); Lyle Creek (13 km 

SW Pullman; 46°42.2′N, 117°28.2′W), 22–29 May 1973, 

W. J. Turner (24♂, 35♀; WSU); Lyle Grove (13 km SW 

Pullman; 46°42.2′N, 117°28.2′W), 4 Jun 1994, R. S. Hanley (1♀; WSU); Pullman (46°43.9′N, 117°10.8′W), 11 Jul 

1988, D. Mathis, W. N. Mathis (1♀; USNM); Pullman 

(46°43.9′N, 117°10.8′W), 26 May–10 Aug 1908, 1911, 

1912, 1921, 1922, 1924, 1955, 1956, V. Argo, C. F. Baker, 

M. Coffey, G. D. Gill, W. M. Mann, A. L. Melander, W. J. 

Turner (27♂, 67♀; USNM, WSU); Pullman (2 km E; 

46°43.9′N, 117°10′W; 740 m), 12 Aug 1994, R. S. Hanley 

(1♂, 3♀; WSU); Pullman, near SCS Pond (46°43.9′N, 

117°10.8′W; Malaise trap), 5 Jun 1972, J. F. MacDonald 

(1♂; WSU); Pullman (7 km ESE on Wilber Gulch Road; 

46°42′N, 117°09′W; 750 m), 13 Jul 1994, R. S. Hanley 

(4♂; WSU); Rosalia (47°14.2′N, 117°22.3′W; on cow 

excrement), 13 Jun 1956, M. Coffey (1♂; WSU); Steptoe 

Butte (6.5 km NE Steptoe; 47°02′N, 117°17.8′W), 11 Jun 

1989, R. S. Zack (2♂, 3♀; WSU); Union Flat (46°49.6′N, 

117°59.9′W), 16 Jun–19 Jul 1916, A. L. Melander (3♀; 

USNM); Uniontown (46°32.2′N, 117°05.2′W), 26 Jun 

1932, J. M. Aldrich (1♂, 2♀; USNM); Wawawai 

(46°38.2′N, 117°22.8′W), 7 May–28 Jul 1911, 1915, 

1956, 1957, R. H. Alvarado, G. D. Gill, A. L. Melander 

(85♂, 154♀; USNM, WSU); Whelan (46°47′N, 117°07′W), 

29 Jun 1998, R. Sanders (1♂, 1♀; WSU). Yakima: American River (46°58.5′N, 121°09.7′W; Malaise trap; 1036 

m), 24 Jul–24 Aug 1976, W. J. Turner (1♂, 1♀; WSU); 

Grandview (46°15′N, 119°54.1′W), 29 Jun 1950, D. Malcolm (2♂; WSU); Mount Adams (46°12.2′N, 121°29.4′W), 

15 Apr–24 Jul 1918, 1921, A. L. Melander, A. L. Mota 

(6♂, 7♀; USNM); North Yakima (46°36.6′N, 120°23.3′W), 

14 May 1903, E. Jenne (1♀; USNM); Prosser (8 km W, 

Route 2; 46°42.1′N, 119°48′W), 14 Jun 1989, R. S. Zack 

(1♀; WSU); Tieton Ranger Station (13 km SW; 46°39.4′N, 

121°07.8′W; Malaise trap with CO2), 24 Jun–16 Jul 1972, 

1974, W. J. Turner (2♂, 2♀; WSU); Yakima (46°36.1′N, 

120°30.4′W), 22 May–18 Jul 1917, 1920, A. L. Melander 

(3♂, 2♀; USNM); Zillah (46°24.1′N, 120°15.7′W), 3 Jun 

1957, E. F. Dailey (1♂; WSU).

Wyoming. Teton: Pilgrim Creek (9.5 km N Jackson 

Lake Junction; 43°52′N, 110°33.2′W, 2225 m), 18–19 

Jul 1994, E. M. Fisher (1♀; CSCA). Uinta: Mountain 

View (8.5 km E; 41°16.1′N, 110°20′W; 2075 m), S. Peck, 

J. Peck (1♀; DEBU).

Distribution (Figure 126). Nearctic: Canada (Alberta, British Columbia), Mexico (Baja 

California, Baja California Sur), United States (Arizona, 

California, Colorado, Idaho, Maryland, Montana, Nevada, New Mexico, Oregon, Texas, Utah, Washington, 

Wyoming).

Remarks. Hackman (1970) examined and 

commented on Fallén’s type material at the Riksmuseum, 

Stockholm. On the basis of his key, comments, and illustrations, it is clear that the North American specimens identified by Melander and others as T. frontalis (Fallén) are not 

conspecific with that examined by Hackman. Hackman 

(p. 129) noted that in males the “Foretibia [is] dark except 

at base, fore basitarsus yellow, third basitarsus dark and 

moderately swollen.” Among specimens we have examined, there is variation in the coloration of the fore tibia 

and fore basitarsus, ranging from black to yellow, while 

the hind basitarsus in always yellow and is slightly to 

moderately swollen. The drawings of the male terminalia 

only vaguely resemble the terminalia of our specimens especially in the configuration of the complex aedeagus and 
8 4 • smithsonian contributions to zoology

the surstylus. His drawing of the aedeagus (his figure 17) 

clearly shows the presence of several dark, thick spicules 

on the mid-dorsal surface similar to those found on the 

aedeagus of T. plebs. This completely rules out T. frontalis 

as being the identity of the North American specimens because they do not have this distinctive feature. We have examined a specimen from Switzerland (Valais) that closely 

fits Hackman’s comments and illustration of T. frontalis

and this further convinces us that the North American species is not the true T. frontalis described by Fallén. Further, 

we have examined specimens from Norway that seem to 

be near the true T. frontalis but do not match the North 

American material. Until an extensive study of Palearctic 

material can be performed, especially type specimens, the 

only valid name for the Nearctic material would seem to 

be Melander’s T. flavida based on structures of the male 

terminalia.

The color of the basal flagellomere exhibits sexual 

dimorphism in this species. Females have a brown area 

in the center while males show an entirely yellow basal 

flagellomere. Additional variation can be observed in the 

general habitus of specimens of this species and rarely the 

fore femur of some males may be entirely yellow. Some 

specimens can be quite pale and fragile while others are 

quite robust with full coloration as described above. It 

seems that Melander mistook pale and fragile specimens 

FIGURE 126. Distribution map for Trixoscelis flavida Melander.
number 637 • 8 5

as a separate species from his “T. frontalis” and named 

them T. flavida.

Trixoscelis lagunaensis Foster and Mathis, 

new species

FIGURES 63, 127–128

Diagnosis. Body gray; thorax with two 

brown vittae between dorsocentral setae and along postprotonal and notopleural line, 4 rows of acrostichal setae; 

wing hyaline, not smoky and without infuscations; antenna mostly yellow, slightly brownish tint in center of 

basal flagellomere; vertex yellowish to light gray microtomentose; gena short, gena-to-eye ratio only 0.19–0.22; 

epandrium small and indistinct in relation to remainder of 

abdomen in undissected specimens.

Description. Body length 1.90–2.33 mm.

Head: Eye higher than wide; ocellar triangle light

gray microtomentose; frons bare, yellow becoming darker 

dorsally, parafrons whitish microtomentose; 2 strong, 

reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short 

cruciate postocellar seta; medial vertical seta strong, widely 

separated and convergent; lateral vertical seta long, strong 

and divergent;occiput gray microtomentose with 1–2 rows 

of short dorsoclinate setulae; antenna mostly yellow except 

brown on dorsal half of basal flagellomere; arista brown, 

with sparse hairs. Gena short, gena-to-eye ratio 0.19–0.22, 

white microtomentose, bearing 1 row of 2–3 short ventroclinate setae along ventral edge in addition to a pair of 

stronger convergent oral vibrissae; face white; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum uniformly gray microtomentose with two indistinct brown vittae between dorsocentral 

setae and along postprotonal and notopleural line, sparsely 

covered with setae much shorter than the dorsocentral setae. 

Dorsocentral setae 5(2+3); acrostichal setae in 4 somewhat 

irregular rows; apical scutellar setae about twice length of 

scutellum. Anepisternum with brownish coloration along 

dorsal half or so, mostly bare except for one strong seta on 

posterodorsal corner along with 3–4 much smaller setulae 

in a cluster; katepisternum with 2 longer setae and several 

very short setulae along the posterodorsal edge. Wing hyaline with brown veins. Halter white. Forecoxa grayish, fore 

femur dark brown to black, slightly swollen; all other femora, tibiae and tarsi yellow except fifth tarsomere darker, 

male hind basitarsus slightly swollen; fore femur with a 

row of longer setae along posterodorsal and posteroventral 

surfaces

Abdomen: Uniformly dark gray microtomentose

except extreme posterior edges of sternites lighter; evenly setose. Male terminalia (Figures 127, 128): Epandrium small 

and indistinct in relation to remainder of abdomen in undissected specimens; surstylus (Figure 127) short, robust, with 

dorsal curvature, rounded distally, with few long, rather 

weak setae on dorsal surface, pre- and postgonites (Figures 

127, 128) fused into one boot-shaped structure, spatulate 

ventrally with row of short but strong setae along ventral 

margin; aedeagus complex (Figure 127) sclerotized. Female 

terminalia: Seventh tergite and sternite forming strong, 

tight ring; spermathecae square-cylindrical; eighth sternite 

with setaceous lateral lobes; hypoproct bare; epiproct with

two weak setulae.

Type Material. The holotype male is labeled 

“Laguna Beach [CAL]IFORNIA 28 Mar 35 ALMelander/

ALMelander Collection 1961 [green stippling on right 

side]/HOLOTYPE ♂ Trixoscelis lagunaensis USNM Foster & Mathis [red]/USNM ENT 00118087 [plastic bar 

code label].” The holotype is double mounted (pinned 

from ventral side with a minuten mounted in a cardboard 

square), is in excellent condition (abdomen removed and 

dissected; structures in an attached microvial), and is deposited in the USNM. Paratypes are as follows:

MEXICO. Baja California Sur. Arroyo San Gregorio 

(13 km WNW of La Purísima; 26°13.6′N, 112°21.8′W), 24 

Apr 1983, M. S. Wasbauer (2♂; CSCA). Rancho Tablon, 

Guillermo Prieto (21 km SW; 27°50′N, 113°19′W), 14–17 

Apr 1983, M. S. Wasbauer (1♂, 2♀; CSCA).

UNITED STATES. California. Orange: Corona 

del Mar (33°35.9′N, 117°52.4′W), 28 Dec 1944, A. L. 

Melander (2♂; USNM); Laguna Beach (33°32.5′N, 

117°47′W), 28 Mar 1935, A. L. Melander (1♂, 1♀; 

USNM). San Diego: La Jolla (32°50.8′N, 117°16.5′W), 29 

Dec 1934, A. L. Melander (1♂; USNM; a syntype, now a 

paralectotype of T. sagulata).

Type Locality. United States. California. Orange: Laguna Beach (33°32.5′N, 117°47′W).

Distribution (Figure 63). Nearctic: 

Mexico (Baja California Sur), United States (California).

Etymology. The species epithet, lagunaensis, 

is of Latin derivation and refers to the type locality: Laguna Beach, California.

Remarks. Like T. barberi, this species is very 

closely allied to T. claripennis but shows distinctive differences in the male terminalia, particularly the surstyli, 

fused gonites, and aedeagus.
8 6 • smithsonian contributions to zoology

Trixoscelis nitidiventris Melander

FIGURES 129–132

Trixoscelis nitidiventris Melander, 1952:47. —Vockeroth, 1965:818 [Nearctic catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Thorax gray with indistinctly 

darker stripes along dorsocentral and inner two rows of 

acrostichal setae, 4 irregular rows of acrostichal setae; 

wing hyaline; antenna mostly yellow except outer 0.66 

of basal flagellomere brown; vertex brown microtomentose; gena short, gena-to-eye ratio 0.15; abdomen brown, 

shiny; male epandrium in undissected specimens black, 

shiny, concolorous with abdomen.

Description. Body length 2.38–2.64 mm.

Head: Eye slightly higher than wide, nearly 

round; ocellar triangle light gray microtomentose; frons 

bare, yellow becoming brown laterad of ocellar triangle; 

parafrons whitish microtomentose; 2 strong, reclinate 

parafrontal setae; ocellar setae 1 strong pair, positioned at 

level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate 

postocellar seta; medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and 

divergent;occiput quite narrow, gray microtomentose with 

1 even row of short dorsoclinate setulae in addition to several scattered setae dorsally and ventrally; antenna mostly 

yellow except outer 0.66 of basal flagellomere brown; 

arista brown, with sparse hairs. Gena short, gena-to-eye 

ratio 0.15, white microtomentose, bearing a neat row of 

setulae along ventral margin only; face white, palpus yellow, clypeus small indistinct, brown.

Thorax: Mesonotum light brown with darker indistinct stripes along dorsocentral setae and inner 2 rows 

of acrostichal setae, sparsely covered with setae much 

shorter than the dorsocentral setae. Pleural area black, 

shiny. Dorsocentral setae 5(2+3); acrostichal setae in 4 

rows; apical scutellar setae about twice length of scutellum. Anepisternum mostly bare except for one strong 

seta on posterodorsal corner along with only 3–4 much 

smaller setulae in a cluster; katepisternum with 2 longer 

FIGURES 127–128. Structures of male terminalia of Trixoscelis lagunaensis Foster 

and Mathis: (127) epandrium, surstylus, gonites, and aedeagus, lateral aspect (California. San Diego: La Jolla); (128) gonites, lateral aspect (California. Orange: Laguna 

Beach). Scale = 0.1 mm.
number 637 • 8 7

setae and several very short setulae along the posterodorsal edge. Wing hyaline, without distinct markings. Halter 

white. All coxae and femora shiny brown to black, fore 

tibia and tarsi black, mid and hind tibiae and tarsi yellow, 

fore femur with a row of longer setae along posterodorsal 

and posteroventral surfaces 

Abdomen: Brown, shiny, evenly setulose. Male 

terminalia (Figures 129–131): Epandrium in undissected 

specimens concolorous with remainder of abdomen; surstylus (Figures 129, 130) narrow, curving into blunt hook 

and narrowing distally, slightly curved anteriorly in lateral 

view, somewhat long triangular in posterior view (Figure 

130); pre- and postgonites (Figure 129) fused, oblong, with 

row of ventrally directed setae along ventral margin; distiphallus with complex sclerotization and series of short, 

blunt spicules on the medial dorsal surface. Female terminalia: Seventh tergite and sternite forming strong, tight ring; 

spermathecae squared-cynlindrical; eighth sternite with distinctly rounded lobes bearing several weak setae; hypoproct 

with several weak setae; epiproct with 2 weak setulae.

Type Material. Melander described nitidiventris from three females from which we herein designate 

one as lectotype. The lectotype female is labeled “Beaumont CAL[IFORNIA] 25/4/44 [25 Apr 1944] A. L. Melander”/HOLOTYPE Trixoscelis nitidiventris Melander 

[red]/Trixoscelis nitidiventris Melander [handwritten]/

LECTOTYPE ♀ Trixoscelis nitidiventris Melander Foster & Mathis USNM/USNM ENT 00118085 [plastic bar 

code label].” The lectotype is double mounted (pinned 

from ventral side with a minuten that is mounted in a 

cardboard square), is in excellent condition, and is deposited in the USNM. Paralectotypes are as follows:

UNITED STATES. California. Riverside: Beaumont 

(33°55.8′N, 116°58.6′W), 25 April 1944, A. L. Melander 

FIGURES 129–131. Structures of male terminalia of Trixoscelis nitidiventris Melander (Oregon. Lake: 16 

km NE Christmas Valley): (129) epandrium, surstylus, and gonites, lateral aspect; (130) epandrium and 

surstyli, posterior aspect; (131) distiphallus, lateral aspect. Scale = 0.1 mm.
8 8 • smithsonian contributions to zoology

(1♀; USNM); Perris (33°47′N, 117°13.7′W), 10 May 

1945, A. L. Melander (1♀; USNM).

Type Locality. United States. California. 

Riverside: Beaumont (33°47′N, 117°13.7′W).

Other Specimens Examined. MEXICO. Baja California: Ensenada (32 km N; 31°52.5′N, 

116°37′W), 1 Apr 1931, A. H. Sturtevant (1♀; USNM).

UNITED STATES. California: Solano: Stebbins Cold 

Canyon (38°30′N, 122°06′W), 250 m, 17 Apr 2005, K. A. 

Williams (1♀; CSCA).

Oregon: Lake: Christmas Valley (16 km NE; 

43°14.3′N, 120°38.2′W), 3 Jul 1971, G. C. Steyskal (4♂; 

3♀; USNM).

Distribution (Figure 132). Nearctic: Mexico (Baja California), United States (California, 

Oregon).

Remarks. The status of this species was uncertain, not having an associated male with the three female 

syntypes. However, we have discovered a mixed series of 

males and females in the USNM collection and now are 

able to clearly establish this species’ identity. The brown 

to black, shiny anepisternum and abdomen and almost entirely black legs are distinguishing characters for this species. The distiphallus of the male indicates an affinity with 

T. plebs in having a series of short, blunt, thick spicules 

on the medial dorsal surface (Figure 131). There are close 

FIGURE 132. Distribution map for Trixoscelis nitidiventris Melander.
number 637 • 8 9

similarities in the form of the surstyli and gonites as well. 

The very black, shiny abdomen and mesonotal sclerites 

along with the nearly entirely dark legs of T. nitidiventris 

clearly distinguish it from T. nuda, which is entirely gray 

microtomentose with yellow legs.

Trixoscelis plebs Melander

FIGURES 133–136, 142–143

Trixoscelis plebs Melander, 1952:48. —Vockeroth, 1965:818 [Nearctic catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Body uniformly gray microtomentose; 4 irregular rows of very minute, weak acrostichal 

setae becoming only 2 rows posteriorly; wing hyaline; 

antenna entirely bright yellow in male, basal flagellomere 

darker in center in female; gena very short, gena-to-eye 

ratio 0.12; male epandrium in undissected specimens 

shiny black, sometimes partially extended and with surstyli evident.

Description. Body length 1.75–2.20 mm.

Head (Figures 142, 143): Eye nearly round, only 

slightly higher than wide; ocellar triangle light gray microtomentose; frons bare, bright yellow becoming only barely 

brownish laterad of ocellar triangle; parafrons whitish microtomentose; 2 strong, reclinate parafrontal setae; ocellar 

setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker 

ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent; occiput narrow, gray 

microtomentose with one row of short dorsoclinate setulae 

in addition to several scattered setae dorsally and ventrally; 

antenna entirely bright yellow in male, female with a dark 

area at base and middle of basal flagellomere, arista yellow 

at extreme base otherwise black, with sparse hairs. Gena 

very short, gena-to-eye ratio 0.12, white or bright yellow 

microtomentose, a row of weak, small sometimes indistinct

setulae along the ventral margin in addition to a pair of 

stronger convergent oral vibrissae; face white, palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae 

very minute and weak, in 4 scattered rows becoming only 

2 rows posteriorly; apical scutellar setae only about twice 

length of scutellum. Anepisternum mostly bare except for 

one strong seta on posterodorsal corner along with only 

3–4 much smaller setulae in a cluster; katepisternum with 

2 longer setae and several very short setulae along the posterodorsal edge in addition to a row of short setulae just 

anterior to the midline of the sclerite. Wing hyaline. Halter 

white. Mid and hind leg entirely yellow, fore femur may 

be darker on apical 1/2 in females or only slightly silvery 

gray, foreleg of male entirely yellow, fore tarsus of female 

also dark, except for distal most segment; fore femur with a 

row of longer setae along posterodorsal and posteroventral 

surfaces, otherwise legs evenly setulose except for preapical tibial seta on all tibiae; male hind basitarsus slightly 

enlarged.

Abdomen: Uniformly gray to brownish microtomentose, evenly setulose. Male terminalia (Figures 133–

135): Epandrium in undissected specimens distinctly shiny 

black or gray, sometimes partially extended and with surstyli evident; surstylus (Figure 133, 134) long, narrowly 

triangular, pointed; pre- and postgonites fused, spatulate, 

simple with a row of long setae ventrally (Figure 135); 

distiphallus (Figure 133) dark, complex, with series of 

thick spicules on dorsum of midshaft that are longer than 

the width of the shaft. Female terminalia: Seventh sternite 

and tergite strongly fused; spermathecae square spherical; 

eighth sternite with distinct somewhat rectangular setaceous lobes; hypoproct with many weak setae; epiproct 

with two weak setae.

Type Material. Melander described T. plebs

from three females and three males from which we herein 

designate one male as lectotype to stabilize the usage of 

this name. Melander (1952) stated that he had two males 

and three females from Travertine Rock, California, and 

one female from Indio, but our examination of the type 

series reveals that the Indio, California, specimen is a male 

as well. The lectotype specimen is labeled “Travertine 

CAL[IFORNIA] 2 May 45 A. L. Melander”/PARATYPE 

Trixoscelis plebs Melander [yellow]/ A. L. Melander Collection 1961 [white label with green stippling on right 

side]/LECTOTYPE ♂ Trixoscelis plebs Melander Foster 

& Mathis USNM/USNM ENT 00118084 [plastic bar 

code label].” The specimen is double mounted (pinned 

from ventral side with a minuten mounted in a cardboard 

square), is in good condition (missing some dorsocentral 

and parafrontal setae), and is deposited in the USNM. 

Paralectotypes are as follows:

UNITED STATES. California. Riverside: Indio 

(33°43.2′N, 116°12.9′W), 2 May 1945, A. L. Melander 

(1♂; USNM). San Diego: Travertine Palms (33°24.1′N, 

116°05.9′W), 2 May 1945, A. L. Melander (1♂, 3♀; 

USNM).
9 0 • smithsonian contributions to zoology

Type Locality. United States. California. San 

Diego: Travertine Palms (33°24.1′N, 116°05.9′W).

Other Specimens Examined. CANADA. 

Saskatchewan: Val Marie (49°14.4′N, 107°43.9′W), 5 Jun 

1955, J. R. Vockeroth (1♂; CNC).

UNITED STATES. California. San Diego: Borrego, 

Palm Canyon (33°13.2′N, 116°20.1′W), 2 May 1945, 

A. L. Melander (1♂; USNM).

Colorado. Rio Grande: South Fork (37°40.2′N, 

106°38.4′W; 2500 m), 20 Jun 1972, W. W. Wirth (1♂; 

USNM).

Nevada. Clark: Las Vegas Wash (36°05.4′N, 

114°58.7′W), 11 Apr 2005, D. Mathis, W. N. Mathis (8♂, 

1♀; USNM); Red Rock Canyon (36°08.7′N, 115°25′W), 

11 May 2001, D. Mathis, W. N. Mathis (1♂; USNM). 

Lincoln: Alamo (6.5 km S; 37°19′N, 115°10′W), 17 May 

2004, D. Mathis (1♂; USNM).

Distribution (Figure 136). Nearctic: 

Canada (Saskatchewan), United States (California, Colorado, Nevada).

Remarks. This species exhibits sexual dimorphism in the foreleg, hind basitarsus, and antenna. 

Females consistently have a darker distal 1/2–2/3 of the 

fore femur and the basal four tarsomeres of the foreleg are 

dark as well. Also, the basal flagellomere of the female has 

a dark area in the middle and at the base. The male hind 

basitarsus is slightly swollen. The gena of this species is 

one of the shortest of the genus. The male terminalia tend 

to be somewhat enlarged and shiny black or gray, and 

many specimens have a strong, rather pointed surstylus 

FIGURES 133–135. Structures of male terminalia of Trixoscelis plebs Melander (Nevada. Clark: Las Vegas Wash): (133) epandrium, 

surstylus, hypandrium, aedeagus, and aedeagal apodeme, lateral aspect; (134) epandrium and surstyli, posterior aspect; (135) s, lateral aspect. Scale = 0.1 mm.
number 637 • 9 1

that is clearly evident. The aedeagus shows a distinctive set 

of long, strong spicules on the midshaft.

Trixoscelis signifera Melander

FIGURES 93–94, 137

Trixoscelis signifera Melander, 1952:49. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Thorax gray microtomentose with 

indistinct brown vittae along dorsocentral line and with a 

more distinct brown line on the dorsal half of the proepisternum, anepisternum, and the extreme ventral portion 

of the postpronotal lobe, 4 irregular rows of acrostichal 

setae; wing darkened anterior to vein R2+3, only slightly 

darkened along tips of vein R4+5 and M, crossvein dm–cu 

distinctly darkened, vein M distinctly darkened between 

crossveins; antenna with scape and pedicel yellowish, 

basal flagellomere mostly brown to very light brown; gena 

short, gena-to-eye ratio 0.15; male epandrium in undissected specimens small, blackish.

Description. Body length 2.05–2.93 mm.

Head: Eye only 2.0 higher than wide; ocellar triangle light gray microtomentose; frons bare, orange becoming 

dark brown or blackish laterad of ocellar triangle; parafrons 

silvery microtomentose; 2 strong, reclinate parafrontal 

setae; ocellar setae 1 strong pair, positioned at level of or 

FIGURE 136. Distribution map for Trixoscelis plebs Melander.
9 2 • smithsonian contributions to zoology

anterior to anterior ocellus, 1 additional posterior pair of 

shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and 

convergent; lateral vertical seta long, strong and divergent; 

occiput short, gray microtomentose with one row of short 

dorsoclinate setulae in addition to several evenly scattered 

setae dorsally and ventrally; antenna with scape and pedicel yellow, basal flagellomere brown or light brown, arista 

dark brown with sparse hairs. Gena short, gena-to-eye 

ratio 0.15, white microtomentose, a row of setulae along

the ventral margin in addition to a pair of stronger convergent oral vibrissae; face white, palpus yellow, clypeus small 

indistinct, brown.

Thorax: Mesonotum gray microtomentose with

indistinct brown vittae along dorsocentral line and with a 

more distinct brown line on the dorsal half of the proepisternum, anepisternum, and the extreme ventral portion of 

the postpronotal lobe. Dorsocentral setae 5(2+3); acrostichal setae weak in 4 irregular rows; apical scutellar setae 

only about twice length of scutellum. Anepisternum mostly 

bare except for one strong seta on posterodorsal corner 

along with only 3–4 much smaller setulae in a cluster; 

katepisternum with 2 longer setae and several very short 

setulae along the posterodorsal edge in addition to a row 

of short setulae just anterior to the midline of the sclerite. 

Wing (Figures 93, 94) darkened anterior to vein R2+3, only 

slightly darkened along tips of vein R4+5 and vein M, crossvein dm–cu distinctly darkened, vein M distinctly darkened 

between crossveins. Halter white. Forelegs with femur and 

tarsi brown, tibia yellow, remaining legs entirely yellow; 

fore femur with a row of longer setae along posterodorsal 

and posteroventral surfaces hind basitarsus of male slightly 

to moderately swollen.

Abdomen: Uniformly brownish microtomentose,

evenly setulose. Male terminalia (identical to T. flavida, 

see Figures 122–125): Epandrium uniformly gray microtomentose, details as in Figures 122–123; surstylus small, 

somewhat teardrop shaped, endowed with many long setae 

along margin; pre- and postgonites (as in Figures 122, 

124–125) fused, oblong, with 2 rows of short setae along

ventral margin; aedeagus (as in Figure 122, 124) complex, 

appearing trilobed, partially sclerotized. Female terminalia: 

Seventh sternite and tergite strongly fused; spermathecae 

square spherical; eighth sternite with reduced but distinct 

setaceous lobes; hypoproct with many weak setae; epiproct 

with two weak setae.

Type Material. Melander described T. signifera from six specimens (1♂, 5♀). He wrote that the 

type is from “Ortega Highway, El Cariso Camp, May 15, 

1946.” This holotype specimen is a female and is labeled 

“Ortega Hi[gh]way El Cariso [33°39.5′N, 117°24.6′W] 

CAL[IFORNIA. Riverside: ] 15/5/46 A. L. Melander”/

HOLOTYPE Trixoscelis signifera Melander [red]/A. L. 

Melander Collection 1961 [white label with green stippling on right side]/Trixoscelis signifera Melander [handwritten white label].” The specimen is double mounted 

(pinned from ventral side with a minuten mounted in a 

cardboard square) and is in excellent condition. Paratypes 

are as follows:

UNITED STATES. California. Monterey: Big Sur 

(36°16.2′N, 121°48.5′W), 17 Jun 1947, A. L. Melander (1♀; USNM). Orange: Laguna Beach (33°32.5′N, 

117°47′W), 28 Mar 1935, A. L. Melander (1♀; USNM); 

San Juan Camp (33°35.9′N, 117°26.7′W), 26 May 1944, 

A. L. Melander (1♀; USNM). San Francisco: San Francisco (37°46.5′N, 122°25.2′W), 1 Aug 1915, A. L. Melander (1♀; USNM). Santa Clara: Palo Alto (37°26.7′N, 

122°09.6′W), 2 Aug 1891 (1♂; USNM).

Type Locality. United States. California. Riverside: Ortega Highway, El Cariso (33°39.5′N, 

117°24.6′W).

Other Specimens Examined. MEXICO. 

Baja California. Arroyo San Gregorio (13 km WNW of 

La Purísima; 26°13.6′N, 112°21.8′W), 24–24 Apr 1983, 

M. S. Wasbauer (2♀; CSCA). Rancho San Ignacio (26 km 

E Rosarito; 32°20.9′N, 117°02.5′W; Malaise trap), 26–27 

Mar 1982, J. Slansky, M. S. Wasbauer (1♀; CSCA).

UNITED STATES. California. Los Angeles: Altadena 

(34°11.4′N, 118°07.9′W), 14 Jun 1979, Little (1♀; 

CSCA); La Crescenta, base of Eagle Canyon (34°23.5′N, 

118°23.3′W; 750–850 m), 26 Apr 2002, 29 Jun 1994, 

S. D. Gaimari (10♂, 14♀; CSCA); La Crescenta, Eagle 

Canyon (South Base Mount Lukens; 34°15′N, 118°15′W; 

600 m), 30 Jun 1994, S. D. Gaimari (1♀; CSCA); Pasadena 

(34°08.9′N, 118°08.7′W), 21 May 1957, J. Hodge (2♀; 

CSCA). Marin: Alpine Lake (37°56.4′N, 122°38.3′W; Lily 

Pond; 460 m), Jun–Jul 1970, D. D. Munroe (1♀; CNC).

Monterey: Pacific Grove (36°37.1′N, 121°55′W), 13 Jul–

27 Aug 1920, A. H. Sturtevant (2♀; USNM). Orange:

Lower San Juan Campground (33°35.9′N, 117°27.7′W), 

29 May 1981, E. M. Fisher (2♀; CSCA); Olive (33°50.2′N, 

117°50.8′W), 24 Jun 1960, C. Johnson (1♂, 1♀; CSCA); 

Ortega Highway, Placentia (33°52.5′N, 117°52.1′W), 

17 Jul 1964, C. Johnson (2♀; CSCA). San Bernardino: 

Bloomington (34°04.2′N, 117°23.8′W), 23 Apr 1951 (2♀; 

CSCA); Rialto (34°06.7′N, 117°22.9′W), 24 Apr, no further date or collector given (1♂; CSCA). San Diego: Bonsall 

(33°17.3′N, 117°13.5′W), 19 Jul 1960, C. Johnson (1♀; 

CSCA); El Cajon (32°47.7′N, 116°57.8′W; pupae Harrisina brillians), H. H. Keifer (2♀; USNM). San Francisco: 
number 637 • 9 3

Golden Gate Park (37°46.6′N, 122°28.8′W), 21–22 Jun 

1960, P. H. Arnaud, Jr. (6♂; 4♀; USNM); San Francisco 

(37°46.5′N, 122°25.2′W), 26–27 Aug 1930, 1959, T. R. 

Haig, H. H. Keifer (2♀; CSCA). San Luis Obispo: Cayucas (35°27′N, 120°54.2′W), 15 Jul 1950 (1♀; CSCA). San 

Mateo: Redwood City (37°29.1′N, 122°14.2′W), 1 Jun 

1960, P. H. Arnaud, Jr. (1♀; USNM) Santa Barbara: Santa 

Barbara, 16 Jun 1953, A. L. Melander (1♂; USNM). Santa 

Clara: Palo Alto (37°26.7′N, 122°09.6′W), 20–31 May 

1921, A. H. Sturtevant (3♀; USNM), 10 Jun 1921, A. H. 

Sturtevant (2♂; USNM). Santa Cruz: Brownlee (Trout 

Gulch Creek Road; 36°58.5′N, 121°54.1′W), 26 Jun 1951 

(1♀; CSCA); Santa Cruz (36°58.5′N, 122°01.9′W), 17 

Jul 1951 (1♀; USNM); Soquel (36°59.3′N, 121°57.4′W), 

29 Jul 1948, Rebuffo (1♂; CSCA). Ventura: Sisar Creek 

(34°25.7′N, 119°06.8′W), 16 Jun 1948, W. W. Wirth (1♂; 

USNM); Ventura (34°16.7′N, 119°17.6′W), 1 Jul 1951 

(1♀; USNM).

Distribution (Figure 137). Nearctic: 

Mexico (Baja California), United States (California).

Remarks. The terminalia of male specimens we 

examined are identical to those of T. flavida. All specimens 

of T. signifera, however, have distinct markings on the 

wings. The wing markings of T. signifera do not show any 

appreciable variation, and among the hundreds of specimens of T. flavida only clear, hyaline wings were expressed. 

The only other difference we can detect is that T. signifera

has indistinct brown vittae along the dorsocentral line of 

setae. Because of the wing markings, which we consider 

to be of significance, we continue to recognize the species 

FIGURE 137. Distribution map for Trixoscelis signifera Melander.
9 4 • smithsonian contributions to zoology

status of T. signifera. On the basis of the male terminalia 

the two species are clearly very closely allied. Molecular 

data may be necessary to determine if this is one species 

with variation in wing markings or two separate species.

Key to Nearctic Species of the T. nuda Species Group

1. All setae and setulae yellow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

All setae and setulae black. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Gena 0.65–0.85 eye height (rarely 0.33) [Figures 166, 167], female basal flagellomere black; male terminalia as in 

Figure 162. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. flava (Coquillett)

Gena 0.33–0.45 eye height, female basal flagellomere yellow; male terminalia not as above. . . . . . . . . . . . . . . . . . . . . . 3

3. Male abdomen usually light gray, ocellar triangle gray, male distiphallus complex, bulbous, scoop-like [Figures 156, 

157]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. coloradensis, new species

Male abdomen yellow, ocellar triangle yellow, male distiphallus simple, strap-like. . . . . . . . . . . T. flavicornis (Melander)

4. Basal flagellomere black [Figures 146, 147] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T. cinerea (Coquillett)

Basal flagellomere yellow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

5. Scutellum often partially or entirely yellow in male, wing yellowish with yellow veins. . . . . . . . . T. melanderi Vockeroth

Scutellum uniformly gray, wing and veins not yellowish. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6. Distiphallus wide, triangular; postgonite curved anteriorly [Figures 185, 186]. . . . . . . . . . . . . . . . . . T. nuda (Coquillett)

Distiphallus narrower; postgonite not sharply curved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7. Postgonite bi-lobed [Figures 148, 150]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. arnaudi, new species

Postgonite not bi-lobed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8. Postgonite rather boot-shaped [Figures 140, 158]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Postgonite lengthened, nearly straight or shallowly recurved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

9. Postgonite rather long, boot shaped to vermiform [Figure 140]. . . . . . . . . . . . . . . . . . . . . . . . . . T. annetteae, new species

Postgonite like a short boot [Figure 158] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. crepida, new species

10. Postgonite long and thin; pregonite with very strong setae directed ventrally, apex blunt [Figure 172] . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. kernensis, new species

Postgonite stouter; pregonite gently curved, pointed [Figure 177]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. litorea (Aldrich)

The nuda Species Group

Diagnosis. The nuda species group is distinguished from the other species groups by the following 

combination of characters.

Head: Gena moderately short to very high, genato-eye ratio 0.26–0.85.

Thorax: Wing hyaline.

Abdomen: Male terminalia: Epandrium small and 

indistinct in relation to remainder of abdomen in undissected specimens. Aedeagus (except in T. coloradensis) a 

simple sclerotized ribbon with basiphallus not distinct; preand postgonites separate but quite simple and with strong 

setulae on the pregonite.

Remarks. Dissection and analysis of the male 

terminalia of over 100 specimens of “T. nuda” have revealed subtle but consistent differences in structures of the 

inner copulatory apparatus and distiphallus of six of the 

species in the T. nuda group (T. annetteae, T. arnaudi, T. 

crepida, T. kernensis, T. litorea, and T. nuda). Thus far 

we can distinguish and identify these six species only by 

examination of these structures, which require dissection. 

We have also discovered that study and comparison of 

these structures requires the same exact orientation. It 

may also be necessary to gently separate the epandrium 

from the inner copulatory apparatus to see these parts 

clearly. A further complicating factor in the identification 

of these species is that there may be some minor variation 

in the exact shape of the pre- and postgonites. However, 

our study of a large number of specimens has not revealed 

any great variation or morphological overlap between species. Both T. melanderi and T. cinerea also seem to be part 

of the T. nuda complex based on the high gena; simple, 

strap-like distiphallus; and simple, lobe-like, unfused gonites with strong setulae on the pregonite.

The monophyly of this species group is well supported, based on the phylogenies we obtained. The reduced but separate gonites and distinctive ribbon-like 

aedeagus are unique in the subfamily. So far as known, 

this species group only occurs in North America. The differences between some species are comparatively small but 

consistent, perhaps indicating recent speciation. The two 

species formerly placed in Zagonia are included in this 

species group.
number 637 • 9 5

Trixoscelis annetteae Foster and Mathis, 

new species

FIGURES 138–141, 144–145

Diagnosis. Thorax uniformly gray microtomentose, subshiny, 2 irregular rows of acrostichal setae; 

wing hyaline; antenna yellow; gena moderately high, 

gena-to-eye ratio 0.33–0.43 or higher; abdomen gray to 

brownish; male epandrium in undissected specimens concolorous with abdomen.

Description. Body length 2.07–2.70 mm.

Head (Figures 144, 145): Eye distinctly higher 

than wide; ocellar triangle light gray microtomentose; frons 

bare, yellow becoming brown laterad of ocellar triangle; 

parafrons whitish microtomentose; 2 strong, reclinate 

parafrontal setae; ocellar setae 1 strong pair, positioned at 

level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate 

postocellar seta; medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and 

divergent; occiput quite wide, gray microtomentose with 

2–3 variable length rows of short dorsoclinate setulae in 

addition to several scattered setae dorsally and ventrally; 

antenna entirely yellow, arista brown, with sparse hairs. 

Gena moderately high, 0.33–0.43, yellow microtomentose, 

many scattered, short setulae in addition to a pair of strong 

convergent oral vibrissae; face yellow, palpus yellow, clypeus small indistinct, brown.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae 

in 2 rows; apical scutellar setae clearly more than twice 

length of scutellum. Anepisternum mostly bare except for 

one strong seta on posterodorsal corner along with only 

3–4 much smaller setulae in a cluster; katepisternum with 

2 longer setae and several very short setulae along the posterodorsal edge in addition to a row of short setulae just 

anterior to the midline of the sclerite. Wing hyaline. Halter 

pale yellow to white. Legs entirely yellow, apical tarsomeres 

slightly darker; fore femur with a row of longer setae along 

posterodorsal and posteroventral edges.

Abdomen: Uniformly gray to brownish microtomentose, evenly setulose. Male terminalia (Figures 138–

140): Epandrium in undissected specimens concolorous 

with remainder of abdomen; surstylus reduced small lobe 

FIGURES 138–140. Structures of male terminalia of Trixoscelis annetteae Foster and Mathis (California. San Diego: Palm Canyon): 

(138) aedeagus, ventral aspect; (139) same, lateral aspect; (140) gonites, lateral aspect. Scale = 0.1 mm.
9 6 • smithsonian contributions to zoology

partially fused to epandrium, barely discernible in some 

specimens; pregonite simple, somewhat triangular lobe 

with several medium-strength setae on the ventral margin; 

postgonite (Figure 140) simple, bare, long, boot-shaped 

to vermiform lobe with a few minute setulae near tip; distiphallus (Figure 138, 139) broad rectangular, bare, with 

weakly sclerotized flanges laterally becoming thin with posteriorly curved strap distally. Female terminalia: Seventh 

tergite and sternite weakly fused; spermathecae spherical; 

eighth sternite without lateral lobes; hypoproct with two 

strong setae; epiproct with two weak setae.

Type Material. The holotype male is labeled 

“PalmCanyon. 27 Feb [19]35 ALMelander/ALMelander 

Collection 1961 [green stippling on right side]/HOLOTYPE ♂ Trixoscelis annetteae Foster & Mathis USNM 

[red]/USNM ENT 00118079 [plastic bar code label].” 

The holotype is double mounted (pinned vertically from 

the venter on a minuten attached to a cardboard square), 

is in excellent condition (abdomen removed and dissected; 

structures in an attached microvial), and is deposited in 

the USNM.

Type Locality. United States. California. San 

Diego: Palm Canyon (33°13.2′N, 116°20.1′W). Paratypes 

are as follows:

UNITED STATES. Arizona. Coconino: Tuba City 

(36°08.1′N, 111°14.4′W; 1432 m; desert grass, shrub, carrion traps), 22–25 Jul 1979, S. Peck, J. Peck (1♂; DEBU).

California. Contra Costa: Lafayette (37°53.1′N, 

122°07.1′W), 6 Apr 1968, D. D. Munroe (1♂; CNC). Del 

Norte: Jedediah Smith Redwoods State Park, Crescent 

Beach (41°43.6′N, 124°09.2′W; swept from mowed grass 

on sand), 2 Jun 2009, K. N. Barber (6♀; DEBU); Jedediah 

Smith Redwoods State Park, Enderts Beach (41°42.2′N, 

124°08.5′W; swept from grass on high bluff), 4 Jun 2009, 

K. N. Barber (3♂, 1♀; DEBU). Kern: Bakersfield (32 km 

NE, Cow Flat Creek; 35°30.1′N, 118°41.6′W; 500 m), 

25 Apr 2002, S. D. Gaimari (3♂; CSCA); Lost Hills (24 

km W; 35°37′N, 119°55′W), 23 Mar 1947, P. H. Arnaud, 

Jr. (2♂; USNM). Los Angeles: Claremont (34°05.8′N, 

117°43.2′W), no date given, Essig (1♂; USNM); Covina 

(34°05.4′N, 117°53.4′W), 7 Jun 1949, Myers (3♂, 4♀; 

CSCA); Mount Lowe (34°13.9′N, 118°06.4′W), 3 Jul 

1917, J. M. Aldrich (1♂; USNM); La Crescenta, base 

of Eagle Canyon (34°23.5′N, 118°23.3′W; 750–850 m), 

26 Apr 2002, S. D. Gaimari (4♂; CSCA); Lancaster (32 

km W; 34°41.9′N, 118°17′W), 26 Mar 1947, A. L. Melander (1♂; USNM); Palmdale (34°34.8′N, 118°07′W), 

27 Mar 1947, A. L. Melander (2♂, 3♀; USNM). Mendocino: Fort Bragg (39°26.8′N, 123°48.3′W), 2 Jul 1973, 

J. R. Vockeroth (1♂; CNC). Merced: Hillmar (37°24.5′N, 

120°51′W; ex. fruitless mulberry), 13 Apr 1962, N. Hill 

(10♂, 5♀; CSCA). Orange: Santa Ana Canyon (33°51.4′N, 

117°49.1′W), 29 Mar 1950, A. L. Melander (1♂; USNM). 

Riverside: Big Bear Lake (34°14.6′N, 116°54.7′W), 

6 Jul 1942, A. L. Melander (5♂, 1♀; USNM); Cajon 

(34°17.9′N, 117°27.4′W), 21 Apr 1949, A. L. Melander 

(1♂; USNM); Cherry Valley (33°58.4′N, 116°58.6′W), 

18 May 1938, Christenson (1♂, 2♀; USNM); Desert Hot 

Springs (33°57.7′N, 116°30.1′W), 4 Apr 1945, A. L. Melander (2♂, 2♀; USNM); Garnet (33°54.1′N, 116°32.7′W), 

4 Apr 1945, A. L. Melander (1♂; USNM); Lake Mathews 

(33°50.6′N, 117°27.7′W), 25 Mar 1958, A. L. Melander 

(1♂; USNM); Morongo Valley (33°57.6′N, 116°31.5′W), 

19–20 Apr 1944, A. L. Melander (14♂, 5♀; USNM); 

Morongo Valley (33°57.6′N, 116°31.5′W; 915 m), 19 

Apr 1955, W. R. M. Mason (1♂, 2♀; CNC); Palm Desert 

(33°43.3′N, 116°22.5′W; yucca flowers), 19 Mar 1955, 

W. R. M. Mason (11♂, 10♀; CNC); Palm Springs (8 km 

W; 33°49.8′N, 116°32.9′W), 6 Apr 1949, A. L. Melander 

(5♂, 1♀; USNM); Pinyon Flat (25.75 km SW of Palm Desert; 33°36.2′N, 116°27.6′W; flowers of Yucca whipplei;

1220 m), 30 Apr 1967, D. Davis (1♂; USNM); Riverside 

(33°58.8′N, 117°22.4′W), 10 Mar 1935, A. L. Melander 

(1♂, 1♀; USNM); Snow Creek, White Water (33°55.5′N, 

116°38.3′W; 460 m), 29 Apr 1955, W. R. M. Mason, W. R. 

Richards (24♂, 26♀; CNC); Thousand Palms (33°48.7′N, 

116°22.6′W), 12 Apr 1960, A. L. Melander (1♂; USNM); 

Thousand Palms (33°48.7′N, 116°22.6′W), 27 Apr 1955, 

W. R. Richards (1♂, 2♀; CNC). San Bernardino: Apple 

Valley (34°30′N, 116°32.2′W), 4–17 May 1955, W. R. M. 

Mason, W. R. Richards (5♂, 23♀; CNC); Boron, Kramer 

Hills (34°55.3′N, 117°28.1′W), 10 May 1955, W. R. 

M. Mason (2♂, 2♀; CNC); Lucerne Valley (34°26.6′N, 

116°58.1′W), 17 May 1960, A. L. Melander (2♂, 2♀; 

USNM); Joshua Tree (24 km NW; 34°16′N, 116°23.6′W), 

14 Apr 1969, R. R. Pinger (5♂, 5♀; USNM); Phelan 

(11.2 km E Baldy Mesa Road; 34°25.6′N, 117°34.3′W; 

pan traps), 15 May–30 Jun 1982, J. T. Huber (22♂, 27♀; 

CNC, DEBU); Pioneertown (1.6 km NW; 34°09.4′N, 

116°29.8′W; in Yucca flowers), 5 May 1981, E. Fisher 

(8♂, 1♀; CSCA); Victorville (34°32.2′N, 117°17.5′W), 

16–24 May 1955, W. R. M. Mason, W. R. Richards 

(38♂, 55♀; CNC); Yucca (34°06.8′N, 116°25.9′W), 16 

Mar 1960, A. L. Melander (6♂, 2♀; USNM). San Diego:

Escondido (20 km N; 33°08′N, 117°05.2′W), 29 Mar 

1960, M. S. Wasbauer (2♂, 6♀; CSCA); Palm Canyon 

(33°13.2′N, 116°20.1′W), 27 Feb 1935, A. L. Melander 

(2♂, 3♀; USNM). Santa Barbara: Lompoc (34°39.7′N, 

120°28.3′W), 3 Jun 1950 (1♂; CSCA). Santa Clara: Coyote (37°13′N, 121°44.4′W), 9 Mar 1947, P. H. Arnaud, 
number 637 • 9 7

Jr. (3♂; USNM); Palo Alto (37°26.7′N, 122°09.6′W), 17 

Apr–10 Jun 1921, A. H. Sturtevant (7♂, 4♀; USNM).

Distribution (Figure 141). Nearctic: 

United States (Arizona, California).

Etymology. The species epithet, annetteae, 

is a genitive Latin patronym to recognize the enthusiastic 

support and encouragement of Ms. Annette Foster, wife 

of the first author. Annette was especially supportive of 

the research and fieldwork that contributed directly to this 

revision on the Nearctic species of Trixoscelis.

Remarks. Structures of the male terminalia 

distinguish this species from the others in the T. nuda complex. The anterior portion of the hypandrium is quite long 

and drawn out, and the distiphallus is bare and has basal 

flanges that vary in the strength of the sclerotization. The 

postgonites are quite distinctive as well.

Trixoscelis arnaudi Foster and Mathis, 

new species

FIGURES 148–152

Diagnosis. Thorax uniformly gray microtomentose, subshiny, 2 irregular rows of acrostichal setae; 

wing hyaline; antenna yellow; gena moderately short, 

gena-to-eye ratio 0.26; abdomen gray to brownish; male 

epandrium in undissected specimens concolorous with 

abdomen.

FIGURE 141. Distribution map for Trixoscelis annetteae Foster and Mathis.
9 8 • smithsonian contributions to zoology

FIGURES 142–147. Photographs of heads: (142) Trixoscelis plebs, anterior aspect; (143) same, lateral aspect; (144) T. annetteae, anterior 

aspect; (145) same, lateral aspect; (146) T. cinerea, anterior aspect; (147) same, lateral aspect.
number 637 • 9 9

Description. Body length 2.22–2.44 mm.

Head: Eye distinctly higher than wide; ocellar triangle light gray microtomentose; frons bare, yellow becoming 

gray laterad of ocellar triangle; parafrons whitish microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 

1 strong pair, positioned at level of or anterior to anterior 

ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical 

seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent; occiput quite wide, gray 

microtomentose with 2–3 variable length rows of short dorsoclinate setulae in addition to several scattered setae dorsally and ventrally; antenna entirely yellow, arista brown, 

with sparse hairs. Gena moderately short, gena-to-eye ratio 

0.26, yellow microtomentose, many scattered, short setulae 

in addition to a pair of strong convergent oral vibrissae; 

face yellow, palpus yellow, clypeus small indistinct, brown.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae 

in 2 rows; apical scutellar setae clearly more than twice 

length of scutellum. Anepisternum mostly bare except for 

one strong seta on posterodorsal corner along with only 

3–4 much smaller setulae in a cluster; katepisternum with 

2 longer setae and several very short setulae along the posterodorsal edge in addition to a row of short setulae just 

anterior to the midline of the sclerite. Wing hyaline. Halter 

white. Legs entirely yellow, except fore femur and apical 

tarsomeres slightly darker; fore femur with a row of longer 

setae along posterodorsal and posteroventral edges.

Abdomen: Uniformly gray to brownish microtomentose, evenly setulose. Male terminalia (Figures 148–

151): Epandrium in undissected specimens concolorous 

with remainder of abdomen; surstylus stronger then T. nuda

but still reduced sparsely setose lobe partially fused to epandrium; pregonite simple extension of the hypandrium, with 

several medium-strength setae on ventral margin; postgonite (Figures 148, 150, 151) bilobed with ventral lobe

drawn down to sharp point, may vary somewhat; distiphallus (Figure 149) narrow strap tapering to a sharp point apically with weakly sclerotized flanges. Female terminalia: 

Seventh tergite and sternite separate, not fused; spermathecae spherical; eighth sternite without lateral lobes; hypoproct with two strong setae; epiproct with two weak setae.

Type Material. The holotype male is labeled 

“OREGON Lake Co VII_3_1971 10mi NE Christmas 

FIGURES 148–151. Structures of male terminalia of Trixoscelis arnaudi Foster and Mathis: (148) aedeagus, aedeagal apodeme, and gonites, lateral aspect; (149) distiphallus, ventral aspect; (150) postgonite, oblique aspect; (151) postgonite, lateral aspect. Scale = 0.1 mm.
100 • smithsonian contributions to zoology

Valley George Steyskal/HOLOTYPE ♂ Trixoscelis arnaudi

Foster & Mathis USNM [red]/USNM ENT 00118078 

[plastic bar code label].” The holotype is double mounted 

(pinned from right side with a minuten mounted in a plastic cube), is in excellent condition (abdomen removed and 

dissected; structures in an attached microvial), and is deposited in the USNM. Paratypes are as follows:

UNITED STATES. California. Kern: Bakersfield (32 

km NE, Cow Flat Creek; 35°30.1′N, 118°41.6′W; 500 m), 

25 Apr 2002, S. D. Gaimari (3♂; CSCA); Los Angeles: La 

Crescenta, base of Eagle Canyon (34°23.5′N, 118°23.3′W; 

750–850 m), 26 Apr 2002, S. D. Gaimari (4♂; CSCA); 

Whitewater Canyon (34°21.4′N, 118°21.2′W), 6 Apr 

1949, W. W. Wirth (1♂; USNM). Monterey: Castroville 

(36°45.9′N, 121°45.5′W; ex. Achillea sp), 20 Jun 1979, 

B. Oliver (9♂, 3♀; CSCA). Riverside: Riverside (33°58.8′N, 

117°22.4′W), 24 Feb 1935, A. L. Melander (1♂, 1♀; 

USNM). San Diego: Anza-Borrego State Park (2.4 km SE 

of Scissors Crossing; 33°05.5′N, 116°27.3′W; 685 m), 18 

Apr 2003, S. D. Gaimari, E. M. Fisher (2♂, 4♀; CSCA). 

San Luis Obispo: Morro Bay (35°20.1′N, 120°51.1′W), 

16 Jun 1947, A. L. Melander (2♂; USNM). Santa Clara: 

Stanford University (37°25.6′N, 122°10.2′W), 23 Apr 

1961, P. H. Arnaud, Jr. (1♂; USNM). Tulare: Ash Mountain (1 km SE, Sequoia National Park Headquarters; 

36°29.9′N, 118°50′W; flume debris trap), 25 Apr 1984, 

R. D. Haines (1♂; CSCA).

Oregon. Lake: Christmas Valley (16 km NE; 

43°14.2′N, 120°38.2′W), 3 Jul 1971, G. C. Steyskal (3♂, 

1♀; USNM).

Washington. Franklin: Eltopia (16.6 km N; 46°28′N, 

119°07.7′W), 29 May 1957, E. F. Dailey (1♂; WSU); 

Pasco (46°14.4′N, 119°06′W; Russian Thistle), 29 May 

1957, E. F. Dailey (1♂; WSU). Grant: Ephrata (47°19′N, 

119°33.2′W), 17 Jun 1918, A. C. Burrill (1♂; WSU).

Type Locality. United States. Oregon. Lake: 

Christmas Valley (16 km NE; 43°14.2′N, 120°38.2′W).

Distribution (Figure 152). Nearctic: 

United States (California, Oregon, Washington).

Etymology. The species epithet, arnaudi, 

is a genitive Latin patronym to recognize and honor Dr. 

Paul H. Arnaud, Jr., who collected one of the paratypes of 

this species and who has generally supported our research 

on Diptera. Paul is an inveterate and enthusiastic collector of Diptera, much to our benefit, and his knowledge 

of localities in the West, especially the sometimes cryptically named sites visited by A. L. Melander, has helped us 

immeasurably.

Remarks. Structures of the male terminalia 

distinguish this species from congeners in the T. nuda

complex. Specimens of this species are rather diminutive 

compared to the other T. nuda complex species.

Trixoscelis cinerea (Coquillett)

FIGURES 95, 146–147, 153–155

Parodinia cinerea Coquillett, 1902:186. —Melander, 1913a:169 [comment 

on synonymy with T. prima]. —Malloch, 1913b:275 [discussion, key].

Trixoscelis cinerea Melander, 1913b:296 [key to Nearctic species of 

Trixoscelis]. —Aldrich, 1929:34 [formal synonymy with T. prima]. 

—Melander, 1952:43 [revision]. —Vockeroth, 1965:817 [Nearctic 

catalog]. —Cole, 1969:433 [distribution, diagnosis].

Trixoscelis prima of authors, not Hendel 1911 [misidentification]. 

—Melander, 1913a:169 [comment on synonymy].

Diagnosis. Body gray; 4 rows of acrostichal 

setae, proepimeral seta present; wing hyaline, not smoky 

and without infuscations; basal flagellomere black, vertex 

yellowish to light gray microtomentose; gena moderately 

high, gena-to-eye ratio at least 0.37; male epandrium in 

undissected specimens gray, concolorous with abdomen.

Description. Body length 2.00–3.66 mm.

Head (Figures 146, 147): Eye higher than wide; 

ocellar triangle light gray microtomentose; frons bare, yellow, parafrons whitish microtomentose; 2 strong, reclinate 

parafrontal setae; ocellar setae 1 strong pair, positioned at 

level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate 

postocellar seta; medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and 

divergent;occiput gray microtomentose with 1–2 rows of 

short dorsoclinate setulae; antenna with basal flagellomere 

black, scape and pedicel orange; arista with sparse hairs. 

Gena moderately high, gena-to-eye ratio 0.37, yellowish 

microtomentose, bearing 2–3 rows of short dorsoclinate

setae along ventral edge in addition to a pair of strong convergent oral vibrissae; face yellow (rarely black); palpus yellow or brown, clypeus small indistinct, yellow.

Thorax: Mesonotum uniformly gray microtomentose, evenly covered with numerous setae much shorter 

than the dorsocentral setae. Dorsocentral setae 5(2+3); 

acrostichal setae in 4 irregular rows; apical scutellar setae 

3× length of scutellum. Anepisternum mostly bare except 

for one strong seta on posterodorsal corner along with 3–4 

much smaller setulae in a short vertical row with the larger 

seta; katepisternum with 2 longer setae and one shorter one 

between them in a row along the posterodorsal edge. Wing 

hyaline with yellowish veins. Halter white to yellow. Coxae, 

femora and tibiae yellow, tarsi darker; fore femur with a 
number 637 • 101

row of longer setae along posterodorsal and posteroventral surfaces; otherwise, legs are evenly setulose except for 

preapical tibial setae on all tibiae.

Abdomen: Uniformly gray microtomentose except

posterior edges of sternites lighter, evenly setose. Male terminalia (Figures 153, 154): Epandrium gray, concolorous 

with abdomen, small capsulate; surstylus small, spatulate, 

completely fused to internal surface of epandrium, only 

evident by an outline and series of setulae (Figure 153); hypandrium small, simple; pregonite apparently fused to hypandrium, anterior ventral margin with several strong setae; 

postgonite (Figure 154) distinct with large posterior spatulate lobe which is bare; aedeagus with no apparent basiphallus, distiphallus darkly sclerotized, simple, thin ribbon-like, 

evenly tapered to point distally. Female terminalia: Eighth 

sternite lacking small setaceous lobes; spermathecae spherical; hypoproct divided, with two strong setae; epiproct with 

two moderately strong setae, longer than hypoproct setae.

Type Material. Coquillett described T. cinerea from three specimens (1♂, 2♀,) that were collected in 

Los Angeles, California, but he did not designate a holotype. We herein designate the male specimen as the lectotype. The lectotype male of Parodinia cinerea Coquillett is 

labeled “Los Angeles Co. CAL[IFORNIA]/Coquillett Collector/Paratype No. 6650 U.S.N.M.[red]/LECTOTYPE ♂

Trixoscelis cinerea (Coquillett) Foster & Mathis USNM/

USNM ENT 00118077 [plastic bar code label].” The lectotype is double mounted (glued to a paper triangle), is 

slightly damaged (missing the left antenna, the posterior 

two dorsocentral setae, all four scutellar setae, both mid 

FIGURE 152. Distribution map for Trixoscelis arnaudi Foster and Mathis.
102 • smithsonian contributions to zoology

legs and one hind leg, and the left wing has been detached 

and re-glued to the paper triangle; the abdomen has been 

removed, dissected and the structures are in an attached 

microvial), and is deposited in the USNM. Paralectotypes 

bear the same label data as the lectotype.

Type Locality. United States. California. Los 

Angeles: Los Angeles (33°49′N, 118°17′W).

Other Specimens Examined. UNITED 

STATES. California. Kern: Kelso Valley (12.8 km S of Weldon; 35°21.1′N, 118°13.2′W; 1220 m; flowers of Yucca 

brevifolia), 15–17 Apr 1967, D. Davis (1♀; USNM). 

Los Angeles: Bob’s Gap Road (NW of Mile High; 34°26 

52′N, 117°43 47′W; 1239 m), 27 May 2003, J. Skevington (3♂, 5♀; CSCA); Elizabeth Lake Canyon (34°33.2′N, 

118°34.7′W), 29 Apr 1952 (1♂; USNM); Tanbark Flats 

(34°12.2′N, 117°45.6′W), 18 Jun 1956, H. W. Michalk (1♀; 

CSCA). Modoc: Fort Bidwell (41°51.6′N, 120°09.1′W), 

24 Apr 1974, T. Haig (1♀; CSCA). Riverside: Gavilan

Hills (33°47.1′N, 117°22.2′W), 4 Nov 1954, A. L. Melander (22♂, 33♀; USNM); Morongo Valley (33°57.6′N, 

116°31.5′W), 18–20 Apr 1944, 1955, W. R. M. Mason, 

A. L. Melander, W. R. Richards (3♂, 1♀; CNC, USNM); 

Palm Desert (33°43.3′N, 116°22.5′W; Yucca flowers), 

19 Mar 1955, W. R. M. Mason (1♂, 3♀; CNC); Pinon 

Flat (26 km SW of Palm Desert; 33°36.2′N, 116°27.6′W; 

flowers of Yucca whipplei; 1220 m), 30 Apr 1967, D. Davis 

(3♂, 2♀; USNM); White Water (33°55.5′N, 116°38.3′W), 

19 Mar–29 Apr 1955, W. R. Richards (5♂, 7♀; CNC). 

San Bernardino: Hidden Valley (34°55.6′N, 116°21.2′W), 

5 May 1958, A. L. Melander (1♀; USNM); Lytle Creek 

(34°15.5′N, 117°30′W), 10 May 1953, A. L. Melander 

(♂;USNM); Mentone (34°04.2′N, 117°08.1′W), 13 May 

1947, A. L. Melander (2♂, 1♀; USNM); Phelan (3.2 km S; 

34°25.2′N, 117°34.3′W), 28 Jun 1945, A. L. Melander (1♀; 

USNM), 24 May 1945, A. L. Melander (2♂, 1♀; USNM); 

Pioneer town (1.6 km NW; 34°09.4′N, 116°29.8′W; in 

Yucca flowers), 5 May 1981, E. Fisher (1♂; CSCA); San 

Bernadine (34°06.5′N, 117°17.4′W; 1100 m), 19 Apr 1967, 

D. Davis (2♀; USNM); Sheep Creek Canyon near Phelan 

(34°25′N, 117°36.4′W), 24 May 1945, A. L. Melander 

(2♂, 1♀; USNM); Verdemont (34°11.6′N, 117°22.1′W), 

9–19 May 1944, 1953, A. L. Melander (5♂, 2♀; USNM). 

San Diego: Cardiff-by-the-Sea (33°01.3′N, 117°16.9′W), 

21–26 Apr 1967, D. Davis (12♂, 10♀; USNM); Dripping 

Springs (33°26.3′N, 116°58.4′W), 4 Apr 1958, A. L. Melander (1♂, 3♀; USNM); Tecate (32°34.6′N, 116°37.7′W), 

2 May 1966, R. Duke (3♂, 3♀; USNM).

Nevada. Lyon: Wellington (7 km NW; 38°45.5′N, 

119°22.6′W), 28 May 1974, M. S. Wasbauer, J. Slansky 

(3♀; CSCA).

Distribution (Figure 155). Nearctic: 

United States (California, Nevada).

Remarks. Aldrich (1929) formally transferred 

Parodinia cinerea to Trixoscelis and stated that one of 

Coquillett’s syntypes (now the paralectotype) of Leria 

nuda from Santa Fe, New Mexico, is also conspecific with 

FIGURES 153–154. Structures of male terminalia of Trixoscelis cinerea (Coquillett) (California. Dan Diego: Cardiff-by-the-Sea): (153) 

epandrium, aedeagus, and aedeagal apodeme, lateral aspect; (154) aedeagus, aedeagal apodeme, gonites, and hypandrium, lateral aspect. 

Scale = 0.1 mm.
number 637 • 103

T. cinerea. Coquillett’s specimen from Santa Fe is labeled 

“Ckll. 3800 StaFe. July [handwritten]/U.S.N.M. Acc. 

30623./Paratype 13100 U.S.N.M.[red label]/Paratype of 

nuda Coq [handwritten].” Our examination of this syntype, however, reveals that it is not T. cinerea, having the 

antenna and thorax yellow. This syntypic specimen keys 

to T. flavens. The second syntype of L. nuda is discussed 

in our treatment of T. nuda.

Aldrich further stated in his treatment of T. cinerea

that it was “necessary to designate a “cotype” of T. cinerea as the type.” This seems to be a typographical error 

because he is clearly referring to the cotypes of T. nuda. 

He further wrote that he will designate the specimen from 

Claremont, California, as the type of T. nuda (this caused 

Hendel’s T. prima to become a synonym of T. nuda because he observes that it is conspecific with specimens on 

which Hendel based T. prima). The syntypes of T. cinerea

are all from Los Angeles, and the only syntype [of the two 

species?] from Claremont is that of T. nuda.

Aldrich disagreed with Melander’s synonymy of Hendel’s T. prima with T. cinerea in the same paragraph, suggesting, instead, that T. prima is a synonym of T. nuda.

We have examined a specimen that is labeled “Claremont 

Cal[ifornia]. Baker/ Cotype (printed) Trixoscelis prima 

Hendel (handwritten) (red label)/ALMelander Collection 

1961 (white label with green stippling on right half).” We 

cannot be certain that it is one of Hendel’s syntypes, but 

from our examination of it we concur with Aldrich’s conclusion that T. prima is a synonym of T. nuda and not 

with Melander’s commentary that T. prima is a synonym 

of T. cinerea. Melander’s designation therefore is actually 

a misidentification.

FIGURE 155. Distribution map for Trixoscelis cinerea (Coquillett).
104 • smithsonian contributions to zoology

This species is distinguished by having most of the 

head and all of the thorax and abdomen light gray microtomentose. The black basal flagellomere, yellowish gena, 

and relatively wide occiput are distinguishing characters 

of T. cinerea. The male terminalia are unusual in lacking a surstylus, and the postgonite is large, smooth, and 

lacks setulae. An unusual variation in the color of the face, 

black versus yellow, was observed in three specimens from 

Morongo Valley, California.

Trixoscelis coloradensis Foster and Mathis, 

new species

FIGURES 13, 156, 157

Diagnosis. Nearly entirely yellow species except abdomen gray in male and ocellar triangle gray in 

both sexes; 2 scattered rows of acrostichal setae, proepimeral seta present; wing hyaline, yellowish; antenna yellow, 

vertex yellow; gena high, gena-to-eye ratio 0.45; abdomen 

gray; male epandrium in undissected specimens gray.

Description. Body length 2.06–2.70 mm.

Head: Eye slightly higher than wide; ocellar triangle

usually gray microtomentose; frons bare, yellow, parafrons 

yellow; 2 strong, reclinate parafrontal setae; ocellar setae 

1 strong pair, positioned at level of or anterior to anterior 

ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical 

seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent;occiput narrow, yellow, 

with 1–2 rows of short dorsoclinate setulae; antenna yellow; arista yellow. Gena high, gena-to-eye ratio 0.45, yellow, bearing 1 row of 4–5 short ventroclinate setae along 

ventral edge in addition to a pair of strong convergent oral 

vibrissae; face yellow; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum entirely yellow. Dorsocentral setae 5(2+3); acrostichal setae in 2 irregular rows; 

apical scutellar setae only twice length of scutellum. 

Mesonotum sparsely covered with minute setae. Anepisternum gray, mostly bare except for one strong seta on 

posterodorsal corner along with 3–4 much smaller setulae 

in a cluster; katepisternum with 2 longer setae and several 

very short setulae along the posterodorsal edge. Wing hyaline, yellowish. Halter yellow. Legs entirely yellow; fore 

femur with a row of longer setae along posterodorsal and 

posteroventral surfaces, 

Abdomen: Uniformly light gray microtomentose in

male, yellow dorsally in female, evenly setose. Male terminalia (Figures 156, 157): Epandrium in undissected specimens 

FIGURES 156–157. Structures of male terminalia of Trixoscelis coloradensis Foster and Mathis (Colorado. Gunnison: Almont): (156) aedeagus, aedeagal apodeme, and pre- and postgonites, lateral aspect; (157) distiphallus, posterior aspect. Scale = 0.1 mm.
number 637 • 105

gray; surstylus reduced to setulose patch on the proximal 

surface of the epandrium; pre- and postgonites separate 

(Figure 156) postgonite narrow, with minute “hook” at the 

distal tip and two minute setulae, pregonite (Figure 156) 

simple, ventral margin with two rather weak setulae; distiphallus with three narrow sclerotized bands, heavily setulose distally (Figures 156, 157). Female terminalia: Seventh 

tergite and sternite weakly fused; spermathecae spherical 

with ducts partly sclerotized; eighth sternite without lateral 

lobes; hypoproct without short, strong setae; epiproct with 

only weak setulae.

Type Material. The holotype male is labeled 

“Almont Colo[rado] 8200ft AHSturtevant Aug[ust] 9 

1957 [“Aug 9” handwritten]/A. H. Sturtevant Collection, 

1970/HOLOTYPE ♂ Trixoscelis coloradensis Foster & 

Mathis USNM [red]/USNM ENT 00118092 [plastic bar 

code label].” The holotype is double mounted (glued to 

a cardboard triangle and lying on its left side), is in good 

condition, and is deposited in the USNM. Paratypes are 

as follows:

UNITED STATES. Colorado. Gunnison: Almont 

(38°39.9′N, 106°50.8′W; 2445 m), 9 Aug 1957, A. H. 

Sturtevant (3♂, 4♀; USNM).

Type Locality. United States: Colorado. 

Gunnison: Almont (38°39.9′N, 106°50.8′W; 2445 m).

Distribution (Figure 13). Nearctic: 

United States (Colorado).

Etymology. The species epithet, coloradensis, is of Latin derivation and refers to the type locality in 

Colorado.

Remarks. This species is closely related to the 

other two species that were previously placed in Zagonia, 

namely T. flava and T. flavicornis. It differs from them in 

having a gray abdomen in the male and a generally gray 

ocellar triangle. Otherwise, it is completely yellow as the 

other two species. The large scoop-like distiphallus is quite 

unique and unusual for the genus.

Trixoscelis crepida Foster and Mathis, 

new species

FIGURES 158–161

Diagnosis. Thorax uniformly gray microtomentose, subshiny; 2 irregular rows of acrostichal setae, 

proepimeral seta present; wing hyaline; antenna yellow; 

gena moderately high, gena-to-eye ratio 0.33–0.43 or 

higher; male epandrium in undissected specimens concolorous with abdomen.

Description. Body length 2.22–2.54 mm.

Head: Eye distinctly higher than wide; ocellar triangle light gray microtomentose; frons bare, yellow becoming brown laterad of ocellar triangle; parafrons whitish 

microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior 

to anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; 

lateral vertical seta long, strong and divergent; occiput quite 

wide, gray microtomentose with 2–3 variable length rows 

of short dorsoclinate setulae in addition to several scattered setae dorsally and ventrally; antenna entirely yellow, 

arista brown, with sparse hairs. Gena moderately high, 

gena-to-eye ratio 0.33–0.43, yellow microtomentose, many 

scattered, short setulae in addition to a pair of strong convergent oral vibrissae; face yellow, palpus yellow, clypeus 

small indistinct, brown.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae 

in 2 rows; apical scutellar setae clearly more than twice 

length of scutellum. Anepisternum mostly bare except for 

one strong seta on posterodorsal corner along with only 

3–4 much smaller setulae in a cluster; katepisternum with 

2 longer setae and several very short setulae along the posterodorsal edge in addition to a row of short setulae just 

anterior to the midline of the sclerite. Wing hyaline. Halter 

pale yellow to white. Legs entirely yellow, apical tarsomeres 

slightly darker; fore femur with a row of longer setae along 

posterodorsal and posteroventral surfaces 

Abdomen: Uniformly gray to brownish microtomentose, evenly setulose. Male terminalia (Figures 158–

160): Epandrium in undissected specimens concolorous 

with remainder of abdomen; surstylus reduced to a small 

lobe partially fused to epandrium, barely discernible in 

some specimens; pregonite simple, ventral margin with 

several weak setae, postgonite (Figure 158) simple, bare, 

short boot-shaped lobe with a few minute setulae near tip; 

distiphallus (Figures 159, 160) broad rectangular, adorned 

with many weak setulae along lateral edges, becoming thin 

posteriorly curved strap distally. Female terminalia: Seventh 

tergite and sternite weakly fused; spermathecae spherical; 

eighth sternite without lateral lobes; hypoproct with two 

strong setae; epiproct with two weak setae.

Type Material. The holotype male is labeled “Husum, Wash[ington]. June 28, 1917[,] A.L. Melander/ALMelander Collection 1961 [green stippling on 

right side]/HOLOTYPE ♂ Trixoscelis crepida Foster & 

Mathis USNM [red]/USNM ENT 00118076 [plastic bar 

code label].” The holotype is double mounted (pinned 
106 • smithsonian contributions to zoology

vertically on a minuten mounted in a cardboard square), 

is in excellent condition (abdomen removed and dissected; 

structures in an attached microvial), and is deposited in 

the USNM. Paratypes are as follows:

UNITED STATES. California. San Bernardino: Barton Flat (34°10.4′N, 116°51.8′W), 12 Jun 1954, A. L. Melander (1♂; USNM); Crestline (34°14.5′N, 117°17.1′W), 

4 Jul 1942, A. L. Melander (1♂; USNM). San Diego: Palomar Mountain (33°19.4′N, 116°52.7′W), 14 Jun 1948, 

A. L. Melander (3♂, 1♀; USNM). Santa Clara: Stanford 

University (37°25.6′N, 122°10.2′W), 23 Apr 1961, P. H. 

Arnaud, Jr. (1♂; USNM).

Type Locality. United States. Washington. 

Klickitat: Husum (45°48′N, 121°29.2′W).

Distribution (Figure 161). Nearctic: 

United States (California, Washington).

Etymology. The species epithet, crepida, is of 

Latin derivation and means boot or sandal, referring to 

the boot-shaped postgonite of this species.

Remarks. This species is remarkably similar to 

T. annetteae in the general shape of the distiphallus. There 

are small but consistent differences, however, in the shape 

of the pre- and postgonites and the distiphallus, which 

is bare in T. annetteae and setulose in T. crepida. It also 

shares the much reduced surstylus with T. annetteae. The 

surstylus of T. nuda is reduced compared to many other 

species of Trixoscelis, but in these two species it is nearly 

indistinguishable.

Trixoscelis flava (Coquillett), 

new combination

FIGURES 162–163, 166–167

Zagonia flava Coquillett in Baker, 1904:27. —Melander, 1913b:297 [diagnosis, distribution]. —Curran, 1934:372 [in key to genera of Chyromyidae]. —Melander, 1952:39 [diagnosis, key]. —Vockeroth, 1965:818 

[Nearctic catalog]. —Cole, 1969:433 [distribution, diagnosis].

Siligo oregona Aldrich, in Aldrich and Darlington, 1908:99. —Melander, 

1913b:297 [diagnosis, distribution, synonymy with Z. flava].

Diagnosis. Body entirely yellow except abdomen may be variable light gray, all setae and setulae 

yellow; 2 rows of acrostichal setae; wing hyaline, slightly 

yellowish; antenna entirely yellow in males, basal flagellomere black in females; gena usually very high, gena-to-eye 

ratio 0.65–0.85; male epandrium in undissected specimens 

concolorous with abdomen.

Description. Body length 3.00–3.80 mm.

Head (Figures 166, 167): Eye round; ocellar triangle yellow; frons bare, yellow, parafrons yellow; 2 strong, 

reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short 

cruciate postocellar seta; medial vertical seta strong, widely 

separated and convergent; lateral vertical seta long, strong 

and divergent;occiput narrow, yellow, with 1 row of short 

dorsoclinate setulae; antenna entirely yellow in males, basal 

flagellomere black in females; arista yellow, with sparse 

hairs. Gena variable but usually very high, gena-to-eye ratio 

0.65–0.85 (rarely 0.33), entirely yellow, bearing 1 row of 

short ventroclinate setae along ventral edge in addition to a 

pair of stronger convergent oral vibrissae; face yellow; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum entirely yellow, all setae and 

setulae yellow. Dorsocentral setae 5(2+3); acrostichal setae 

in 2 somewhat irregular rows; apical scutellar setae about 

twice length of scutellum. Anepisternum mostly bare except for one strong seta on posterodorsal corner along 

with 3–4 much smaller setulae in a cluster; katepisternum 

with 2 longer setae and several very short setulae along 

FIGURES 158–160. Structures of male terminalia of Trixoscelis 

crepida Foster and Mathis (California. San Diego: Palomar Mountain): (158) gonites and hypandrium, lateral aspect; (159) aedeagus, 

ventral aspect; (160) same, lateral aspect. Scale = 0.1 mm.
number 637 • 107

the posterodorsal edge. Wing hyaline to slightly yellowish. 

Halter yellow. Legs entirely yellow; male hind basitarsus 

slightly swollen; fore femur with a row of longer setae along 

posterodorsal and posteroventral surfaces

Abdomen: Entirely yellow or variable light gray in

males, all setulae yellow, evenly setose. Male terminalia (Figure 162): Epandrium in undissected specimens concolorous 

with abdomen; surstylus absent, reduced to small, oval, setaceous patch on the proximal surface of the epandrium, 

pre- and postgonites separate (Figure 162), pregonite with 

a ventral knob of several strong setae, postgonite with one

strong distal seta, distiphallus rather simple, pointed strap 

(Figure 162). Female terminalia: Seventh tergite and sternite 

weakly fused; spermathecae long, narrow over 7× longer 

than wide, without spherical head; eighth sternite without 

lateral lobes; hypoproct with 2 short, strong setae; epiproct 

with only weak setae.

Type Material. Coquillett described this species on the basis of a single female that is labeled “Santa 

Clara Co[unty]. Cal[ifornia] Baker/Type 7680 U.S.N.M. 

[red typewritten label, the number is handwritten]/

Zagonia flava Coq [white handwritten label with black 

border]. The holotype is pinned directly, is in excellent 

condition (verdigris on pin above and below specimen), 

and is deposited in the USNM (7680).

Aldrich and Darlington (1908) described Siligo oregona from five specimens (3♂, 2♀; USNM) that he 

stated were collected at Hood River, Oregon, in July. We 

have located four male syntypes. These specimens comprise the type series even though the date of collection 

FIGURE 161. Distribution map for Trixoscelis crepida Foster and Mathis.
108 • smithsonian contributions to zoology

is incorrect (August rather than July) in the publication 

and all specimens available to us are males. We have not 

located the fifth syntype. As a holotype was not designated, we here designate one of the males as the lectotype. 

The lectotype male is labeled “Hood R[iver] Ore[gon] 

Aug[ust] 7. 02 [handwritten]/Siligo oregona Type [white; 

handwritten]/J. M. Aldrich coll/Cotype 44834 U.S.N.M. 

[red; number handwritten]/LECTOTYPE ♂ Siligo oregona Coquillett Foster & Mathis USNM [red]/USNM 

ENT 00118073 [plastic bar code label].” The lectotype 

is directly pinned, is in excellent condition, and is deposited in the USNM. The other three males are here designated as paralectotypes. One male has had the abdomen 

removed and dissected and the parts are in an attached 

microvial.

Type Locality. United States. California. 

Santa Clara County (37°14′N, 121°46′W).

Other Specimens Examined. UNITED 

STATES. California. Fresno: Sanger (36°42.5′N, 

119°33.4′W), 25 Apr 1949, R. E. Ryckman (1♂, 2♀; 

USNM). Los Angeles: Elizabeth Lake Canyon (34°33.2′N, 

118°34.7′W), 3 Apr 1952, D. Shepherd (1♂; USNM); Fish 

Canyon (34°09.4′N, 117°55.4′W), 24 Apr, A. H. Sturtevant 

(1♀; USNM); Mojave Desert, Big Rock Wash (34°40′N, 

117°52.3′W), 12 May 1944, A. L. Melander (1♀; USNM); 

Pasadena (34°08.9′N, 118°08.7′W), 17 Apr 1929, A. H. 

Sturtevant (1♂, 1♀; USNM). Mariposa: Yosemite Valley (37°43′N, 119°39.9′W), 22 May 1908, E. T. Cresson, Jr. (1♂, 3♀; USNM). Mono: Mono Lake (38°01′N, 

119°0.6′W), 11 Aug 1951, E. L. Kessel (1♂; USNM). 

Riverside: Palm Springs (33°49.8′N, 116°32.7′W), 2 Apr 

1945, A. L. Melander (1♂; USNM); Riverside (33°58.5′N, 

117°19.7′W), 5–19 May 1935, A. L. Melander (4♂, 

4♀; USNM). San Bernardino: Victorville (34°32.2′N, 

117°17.5′W), 10–22 May 1945, 1952, A. L. Melander, 

A. H. Sturtevant (1♂, 2♀; USNM). Santa Clara: San Jose 

(37°19′N, 121°53.3′W; light trap), 5 Jun 1933, L. W. 

Saylor (1♀; USNM). Toulumne: Pinecrest (38°11.3′N, 

119°59.5′W), 12 Jul 1948, P. H. Arnaud, Jr. (1♀; USNM). 

Tulare: Kern Canyon (36°17.9′N, 118°24.3′W), 1 Apr 

1950, A. H. Sturtevant (1♂, 1♀; USNM).

Oregon. Benton: Corvallis (44°33.9′N, 123°15.7′W), 

6 May–21 Jun 1925, 1950, R. W. Lauderdale, A. L. Melander (1♂, 3♀; USNM). Sherman: The Dalles (15 km E; 

45°35.7′N, 121°08′W; 122 m, sand dunes along Columbia 

River), 26 Jun 1975, W. J. Turner (10♂, 19♀; WSU).

Utah. Rich: Garden City (41°56.8′N, 111°23.6′W), 

15 Jul 1951, F. C. Harmston, (1♂; USNM).

Washington. Asotin: Grande Ronde (Snake River; 

46°04.8′N, 116°58.8′W), 9 May 1925, A. L. Melander (1♂, 2♀; USNM). Benton: Prosser (46°12.4′N, 

119°48′W), 4 May 1919, A. L. Melander (1♂; USNM); 

Richland (46°17.3′N, 119°17.5′W), 7 Jun 1974, N. 

E. Woodley, (6♀; WAS). Clallam: Dungeness (48°08.8′N, 

123°07.4′W), 24 Aug 1910 (1♀; USNM). Whitman: Almota (46°42.2′N, 117°28.2′W), 24 Jun 1911, Baker, 

J. M. Aldrich (19♂, 17♀; USNM); Alpowa (46°25.2′N, 

117°11.8′W), 16 Jun 1923, A. L. Melander (1♀; USNM); 

Wawawai (46°38.2′N, 117°22.8′W), 20 May 1911, 7 May 

1915, A. L. Melander (1♂, 7♀; USNM).

Distribution (Figure 163). Nearctic: 

United States (California, Oregon, Utah, Washington)

FIGURE 162. Structures of male terminalia of Trixoscelis flava (Coquillett): pre- and postgonites, 

aedeagus, and aedeagal apodeme, lateral aspect. Scale = 0.1 mm.
number 637 • 109

Remarks. This species is clearly a part of the 

T. nuda species complex. The absent surstylus, reduced 

gonites and strap-like distiphallus are characters shared 

with the other members of the group. It is clearly distinguished from the others, except T. flavicornis, by the 

entirely yellow setae, setulae and body. Both it and T. flavicornis were once placed in a separate genus, Zagonia. 

We have noted some variation in the color of the abdomen 

with some specimens exhibiting a grayish color. The distiphallus of T. flava is narrower than that of T. flavicornis. 

The most obvious genitalic difference is in the form of the 

gonites. The genal height of T. flava is much greater than 

T. flavicornis as well.

Trixoscelis flavicornis (Melander), 

new combination

FIGURES 164–165, 168–169

Zagonia flavicornis Melander, 1952:39. —Vockeroth, 1965:818 [Nearctic 

catalog]. —Cole, 1969:433 [distribution, diagnosis].

Diagnosis. Body entirely yellow, all setae and 

setulae yellow; 2 rows of acrostichal setae; wing hyaline, 

slightly yellowish; antenna entirely yellow; gena moderately high, gena-to-eye ratio 0.33–0.45; epandrium in undissected specimens concolorous with abdomen.

FIGURE 163. Distribution map for Trixoscelis flava (Coquillett).
110 • smithsonian contributions to zoology

Description. Body length 2.54–2.86 mm.

Head (Figures 168, 169): Eye round; ocellar triangle yellow; frons bare, yellow, parafrons yellow; 2 strong, 

reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short 

cruciate postocellar seta; medial vertical seta strong, widely 

separated and convergent; lateral vertical seta long, strong 

and divergent; occiput narrow, yellow, with 1 row of short 

dorsoclinate setulae; antenna entirely yellow; arista yellow, 

with sparse hairs. Gena moderately high but variable, genato-eye ratio usually 0.33–0.45, entirely yellow, bearing 1 

row of short ventroclinate setae along ventral edge in addition to a pair of stronger convergent oral vibrissae; face 

yellow; palpus yellow, clypeus small indistinct, yellow.

Thorax: Mesonotum entirely yellow, all setae and 

setulae yellow. Dorsocentral setae 5(2+3); acrostichal setae 

in 2 somewhat irregular rows; apical scutellar setae about 

twice length of scutellum. Anepisternum mostly bare except for one strong seta on posterodorsal corner along with 

3–4 much smaller setulae in a cluster; katepisternum with 

2 longer setae and several very short setulae along the posterodorsal edge. Wing hyaline, slightly yellowish. Halter 

yellow. Legs entirely yellow; fore femur with a row of longer setae along posterodorsal and posteroventral surfaces

Abdomen: Entirely yellow, all setulae yellow, 

evenly setose. Male terminalia (Figure 164): Epandrium in 

undissected specimens concolorous with abdomen; surstylus absent, reduced to small, oval, setaceous patch on the 

proximal surface of the epandrium, pre- and postgonites 

separate (Figure 164), pregonite simple, with two strong

setae on ventral margin, postgonite (Figure 164) long, narrow, lacking strong distal seta; distiphallus rather simple, 

pointed strap. Female terminalia: Seventh tergite and sternite weakly fused; spermathecae spherical, spermathecal 

ducts as strongly sclerotized as the spermathecae; eighth 

sternite without lateral lobes; hypoproct with 2 short setae; 

hypoproct with weak setae.

Type Material. Trixoscelis flavicornis was 

described from 16 specimens from Omak and Pullman, 

Washington, according to Melander (1952). We have 

found 13 specimens (1♂, 9♀, 3 with missing abdomens) 

from Omak (19 May 1916 not 29 May) and one from 

Pullman (♀) with type labels. Additionally, we have found 

one specimen from North Yakima with a paratype label, 

but this specimen has no type status because Melander 

did not include it. Because Melander did not designate 

a holotype, we herein designate one of the female specimens as lectotype (the male being in poor shape). The 

lectotype is labeled “Omak Wash[ington] 19 May [19]16 

ALMelander/ALLOTYPE Zagonia flavicornis Melander 

[red]/A. L. Melander Collection 1961 [white label with 

green stippling on right side]/LECTOTYPE ♀ Zagonia flavicornis Melander Foster & Mathis USNM [red]/USNM 

ENT 00118089 [plastic bar code label].” It is double 

mounted (minuten pinned ventrally and glued in a cardboard square), is in excellent condition, and is deposited 

in the USNM. Paralectotypes are as follows:

UNITED STATES. Washington. Okanogan: Omak 

(48°24.7′N, 119°31.7′W), 19 May 1919 (1♂, 9♀, 3 unknown sex; USNM). Whitman: Pullman (46°43.9′N, 

117°10.8′W), 4 Jun 1922 (1♀; USNM).

Type Locality. United States. Washington. 

Okanogan: Omak (48°24.7′N, 119°31.7′W).

Other Specimens Examined. UNITED 

STATES. California. Inyo: North Lake Campground (32 

km W Bishop; 37°13.7′N, 118°37.6′W; 2744 m), 27 Jul 

1963, I. Savage (1♀; CSCA). Mono: Mono Lake (38°01′N, 

119°0.6′W), 22 Jul 1911, J. M. Aldrich (14♀; USNM).

Washington. Okanogan: Conconully, Salmon 

Meadows (48°32.8′N, 119°44.9′W; 1372 m; Malaise trap 

with dry ice), 23–23 Jul 1975, W. J. Turner (1♀; WAS); 

Wauconda (11.5 km SE; 48°43.6′N, 118°58′W; Route 30), 

28 Jul 1973, W. J. Turner (1♂; WAS). Whitman: Wawawai 

(46°38.2′N, 117°22.8′W), 13 May 1956, G. D. Gill (1♀; 

WAS). Yakima: North Yakima (46°36.6′N, 120°23.3′W), 

8 May 1903, E. Jenne (1♀; USNM).

Distribution (Figure 165). Nearctic: 

United States (California, Washington).

Remarks. This species is very close to T. flava. 

The most obvious differences are that the females of T. flavicornis exhibit a yellow basal flagellomere as compared to 

the black basal flagellomere of T. flava, the gena is slightly 

shorter as compared to the eye height in T. flavicornis,

and they are smaller in size. The male terminalia show 

FIGURE 164. Structures of male terminalia of Trixoscelis flavicornis

(Melander): pre- and postgonites, lateral aspect. Scale = 0.1 mm.
number 637 • 111

substantial differences in the postgonite (Figures 162, 

164). The distiphallus is slightly wider than in T. flava but 

still is a rather thin strap-like structure. We have chosen to 

only illustrate the gonite complex because the other differences in the male terminalia are slight.

Trixoscelis kernensis Foster and Mathis, 

new species

FIGURES 172–174

Diagnosis. Thorax uniformly gray microtomentose, subshiny; 2 irregular rows of acrostichal setae; 

wing hyaline; antenna yellow gena moderately high, 

gena-to-eye ratio at least 0.33–0.43; male epandrium in 

undissected specimens concolorous with abdomen.

Description. Body length 2.44–3.71 mm.

Head: Eye distinctly higher than wide; ocellar triangle light gray microtomentose; frons bare, yellow becoming brown laterad of ocellar triangle; parafrons whitish 

microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior 

to anterior ocellus, 1 additional posterior pair of shorter, 

weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical seta strong, widely separated and convergent; 

lateral vertical seta long, strong and divergent; occiput 

quite wide, gray microtomentose with 2–3 variable length 

rows of short dorsoclinate setulae in addition to several 

FIGURE 165. Distribution map for Trixoscelis flavicornis (Melander).
FIGURES 166–171. Photographs of heads: (166) Trixoscelis flava, anterior aspect; (167) same, lateral aspect; (168) T. flavicornis, anterior 

aspect; (169) same, lateral aspect; (170) T. nuda, anterior aspect; (171) same, lateral aspect.
number 637 • 113

scattered setae dorsally and ventrally; antenna entirely yellow, arista brown, with sparse hairs. Gena moderately high, 

gena-to-eye ratio 0.33–0.43, yellow microtomentose, many 

scattered, short setulae in addition to a pair of strong convergent oral vibrissae; face yellow, palpus yellow, clypeus 

small indistinct, brown.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than 

the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae in 2 rows; apical scutellar setae clearly more 

than twice length of scutellum. Anepisternum mostly bare 

except for one strong seta on posterodorsal corner along 

with only 3–4 much smaller setulae in a cluster; katepisternum with 2 longer setae and several very short setulae 

along the posterodorsal edge in addition to a row of short 

setulae just anterior to the midline of the sclerite. Wing 

hyaline. Halter pale yellow to white. Legs entirely yellow, 

apical tarsomeres slightly darker; fore femur with a row 

of longer setae along posterodorsal and posteroventral 

edges.

Abdomen: Uniformly gray to brownish microtomentose, evenly setulose. Male terminalia (Figure 172, 

173): Epandrium in undissected specimens concolorous 

with remainder of abdomen; surstylus as in T. nuda; pregonite simple, with several rather strong setae on the ventral 

margin; postgonite (Figure 172) simple, thin, long, somewhat curved lobe with single weak subapical seta; distiphallus (Figure 173) long triangular, nearly bare. Female 

terminalia: Seventh tergite and sternite weakly fused; spermathecae spherical; eighth sternite without lateral lobes; 

hypoproct with two strong setae; epiproct with two weak 

but long setae.

Type Material. The holotype male is labeled 

“KernCo.CALIF[ORNIA] Kelso Valley 8mi. S.Weldon 

Apr. 15–17, 1967 D. Davis 4000′/From Flowers Yucca 

Brevifolia/HOLOTYPE ♂ Trixoscelis kernensis Foster & 

Mathis USNM [red]/USNM ENT 00118075 [plastic bar 

code label].” The holotype is double mounted (glued on 

right side to a paper triangle), is in excellent condition (abdomen removed and dissected; structures in an attached 

FIGURES 172–173. Structures of male terminalia of Trixoscelis kernensis Foster and Mathis (California. 

Kern: Kelso Valley, Weldon): (172) gonites, lateral aspect; (173) hypandrium, gonites and distiphallus, 

ventral aspect. Scale = 0.1 mm.
114 • smithsonian contributions to zoology

microvial), and is deposited in the USNM. Paratypes are 

as follows:

UNITED STATES. California. Kern: Kelso Valley 

(13 km S of Weldon; 35°21.1′N, 118°13.2′W; 1220 m; 

flowers of Yucca brevifolia), 15–17 Apr 1967, D. Davis 

(19♂, 13♀; USNM). Marin: Point Reyes (38°0.1′N, 

122°59.8′W), 19 Apr 1980, S. A. Marshall (1♂; DEBU). 

Monterey: Pacific Grove (36°37.1′N, 121°55′W), 27 Aug 

1920, A. H. Sturtevant (2♂; USNM). Riverside: Morongo, between Morongo and Yucca Valleys (33°57.6′N, 

116°31.5′W), 28 Apr 1932, S. O. McKelvey (3♂, 1♀; 

USNM). San Bernardino: Verdemont (34°11.6′N, 

117°22.1′W), 18 Feb 1958, A. L. Melander (1♂; USNM); 

Wrightwood (34°21.6′N, 117°38′W), 22 May 1954, A. L. 

Melander (3♂, 1♀; USNM). San Francisco: San Francisco 

(37°46.5′N, 122°25.2′W; Lupinus arboreus), 11 Jul–8 

Aug 1929, 1933, H. H. Keifer (5♂, 1♀; CSCA). San Luis 

Obispo: Pismo Beach (35°09.6′N, 120°38.7′W; Lupine, 

sand), 2 Jul 1954, M. T. James (2♂, 2♀; WSU).

Type Locality. United States. California. 

Kern: Kelso Valley (13 km S of Weldon; 35°21.1′N, 

118°13.2′W; 1220 m).

Distribution (Figure 174). Nearctic: 

United States (California).

Etymology. The species epithet, kernensis, 

refers to the type locality in Kern County, California.

Remarks. This species shares a larger, more 

obvious surstylus with T. nuda. The postgonite is unusually long and narrow and shows slight variation in the 

extent of its curvature.

FIGURE 174. Distribution map for Trixoscelis kernensis Foster and Mathis.
number 637 • 115

Trixoscelis litorea (Aldrich)

FIGURES 175–178

Siligo litorea Aldrich, in Aldrich and Darlington, 1908:100.

Trixoscelis litorea. —Melander, 1913b:296 [generic combination; key to 

Nearctic species of Trixoscelis]. —Melander, 1952:42, 47 [in key and 

compared briefly to T. nitidiventris, revision]. —Vockeroth, 1965:818 

[Nearctic catalog]. —Cole, 1969:434 [distribution, diagnosis].

Diagnosis. Thorax and abdomen gray, subshiny, 2 rows of acrostichal setae; wing hyaline; antenna 

mostly yellow outer surface of flagellomere darker; vertex 

light gray microtomentose; gena moderately short, genato-eye ratio 0.26 (rarely 0.43); male epandrium in undissected specimens slightly lighter gray or concolorous than 

abdomen.

Description. Body length 2.20–3.71 mm.

Head: Eye slightly to distinctly higher than wide,

rarely nearly round; ocellar triangle light gray microtomentose; frons bare, yellow becoming brown laterad of ocellar triangle; parafrons whitish microtomentose; 2 strong, 

reclinate parafrontal setae; ocellar setae 1 strong pair, positioned at level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 

short cruciate postocellar seta; medial vertical seta strong, 

widely separated and convergent; lateral vertical seta long, 

strong and divergent;occiput wide, gray microtomentose 

with 2–3 variable length rows of short dorsoclinate setulae 

in addition to several scattered setae dorsally and ventrally; 

antenna mostly yellow, outer surface of flagellomere rarely 

darker; arista brown, with sparse hairs. Gena moderately 

high, gena-to-eye ratio 0.26 (rarely 0.43), yellow microtomentose, bearing several scattered setulae in addition to a

pair of strong convergent oral vibrissae; face usually yellow, 

rarely somewhat darker; palpus yellow, clypeus small indistinct, brown.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than the 

dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal 

setae in 2 rows; apical scutellar setae about twice length of 

scutellum. Anepisternum mostly bare except for one strong 

seta on posterodorsal corner along with only 3–4 much 

smaller setulae in a cluster; katepisternum with 2 longer 

setae and several very short setulae along the posterodorsal edge. Wing hyaline. Halter pale yellow to white. Femora rarely light brown usually entirely yellow, tibiae very 

light brown to yellow, tarsi yellow except for apical two 

segments brownish; fore femur with a row of longer setae 

along posterodorsal and posteroventral surfaces

Abdomen: Uniformly gray to brownish microtomentose, evenly setulose. Male terminalia (Figures 

175–177): Epandrium (Figures 175, 176) in undissected 

specimens concolorous with remainder of abdomen; surstylus as in T. nuda; pregonite simple, with several rather 

strong setae on ventral margin in addition to weak seta on 

posterior edge; postgonite (Figure 177) simple, thin, long, 

somewhat curved, bare lobe; distiphallus (Figures 175, 

177) long, rectangular basally, extended as long curved narrow strap distally, nearly bare. Female terminalia: Seventh 

sternite and tergite weakly fused; spermathecae spherical; 

eighth sternite lacking setaceous lobes; hypoproct with two 

short but strong setae; epiproct with pair of moderately 

strong setae.

Type Material. The holotype male of Siligo litorea Aldrich is labeled “Pacific Grove [36°37.1′N, 

121°55′W] Cal[ifornia. Monterey:], May 8.06 [handwritten]/Upper Beach (Zone 2) [handwritten]/Siligo litorea 

Type Ald. [handwritten]/Type No. 44823 U.S.N.M.[red]/

Trixoscelis litorea Ald. [handwritten].” The specimen is 

double mounted (pinned ventrally with a minuten inserted 

in a small cardboard square), is in good condition, and is 

deposited in the USNM (44823).

Type Locality. United States. California. 

Monterey: Pacific Grove (36°37.1′N, 121°55′W).

Other Specimens Examined. UNITED 

STATES. California. Los Angeles: Los Angeles (33°49′N, 

118°17′W), 25 Apr–7 May 1928, 1950, H. M. Armitage 

(2♂, 2♀; USNM); Mojave Desert, Piute Butte (34°39.5′N, 

117°51′W), 12 May 1944, A. L. Melander (3♂, 1♀; 

USNM); Temecula (33°29.6′N, 117°08.9′W), 10 Mar 

1950, A. H. Sturtevant (1♂; USNM). Merced: Hillmar 

(37°24.5′N, 120°51′W; ex. fruitless mulberry), 13 Apr 

1962, N. Hill (3♂; USNM). Orange: Santa Ana Canyon 

(33°51.4′N, 117°49.1′W), 29 Mar 1950, A. L. Melander 

(1♂; USNM). Riverside: Cajon (34°17.9′N, 117°27.4′W), 

25 Mar 1947, A. L. Melander (1♂; USNM); Riverside 

(33°58.8′N, 117°22.4′W), 22 Feb–19 May 1935, 1946, 

A. L. Melander (20♂; 3♀; USNM); Riverside (33°58.8′N, 

117°22.4′W), 18 May 1950, A. L. Melander (1♂; USNM). 

San Bernardino: Victorville (34°32.2′N, 117°17.5′W), 

2–10 May 1952, 1953, G. A. Marsh, R. O. Schuster, A. H. 

Sturtevant Collection (12♂, 17♀; USNM). San Diego: Escondido (33°07.5′N, 117°04.8′W), 26 Mar 1955, A. H. 

Sturtevant (3♂, 1♀; USNM); Oak Grove (33°23.1′N, 

116°47.4′W), 8–9 May 1945, A. L. Melander (5♂; 2♀; 

USNM). Ventura: Santa Paula (34°21.3′N, 119°03.6′W), 

5 May 1949, H. H. Keifer (1♂, 1♀; USNM).

Distribution (Figure 178). Nearctic: 

United States (California).
116 • smithsonian contributions to zoology

Remarks. Fortunately, the aedeagus and one 

postgonite are visible on the type specimen, easily matching the type with a number of specimens collected later by 

Melander and others in California. The type specimen is 

unusual in exhibiting a slightly darker aspect than more 

recent specimens and it has a darker face. This species is 

clearly a member of the T. nuda species complex based on 

the diminutive surstylus and the morphology of the gonites and aedeagus.

Melander collected this species and T. nuda at the same 

locality and date (Riverside, 24 Feb 1935) in one instance. 

It is unknown if they actually were collected together at 

the same site or if Melander moved around the Riverside 

area and collected them in different habitats. These species appear identical externally, but the differences in the 

male terminalia are substantial and reliable, particularly in 

the shape of the aedeagus and the pre- and postgonites. 

There is some minor difference in the shape of the anterior

FIGURES 175–177. Structures of male terminalia of Trixoscelis litorea (Aldrich) (California. Merced: Hilmar): (175) epandrium, surstylus, aedeagus, aedeagal apodeme, and hypandrium, lateral aspect; (176) epandrium, posterior aspect; (177) aedeagus, aedeagal apodeme and gonites, 

lateral aspect. Scale = 0.1 mm.
number 637 • 117

portion of the hypandrium as well. T. nuda exhibits a 

slightly longer hypandrium anteriorly than T. litorea.

Trixoscelis melanderi Vockeroth

FIGURES 179–182

Trixoscelis dimidiata Melander, 1952:45 [preoccupied, Hendel (1913:617)]. 

—Vockeroth, 1965:818 [Nearctic catalog]. —Cole, 1969:433 [distribution, diagnosis].

Trixoscelis melanderi Vockeroth, 1965:818 [new name for dimidiata preoccupied by Hendel (1913)].

Diagnosis. Thorax uniformly gray microtomentose, scutellum often yellowish medially, 2 rows of 

acrostichal setae; wing yellowish hyaline with darker yellow veins; antenna completely yellow; vertex yellowish orange; gena high, gena-to-eye ratio 0.53; male epandrium 

in undissected specimens gray with yellow highlights.

Description. Body length 2.20–2.75 mm.

Head: Head higher than wide. Eye slightly higher

than wide; ocellar triangle light gray microtomentose; frons 

bare, uniformly orange; parafrons silvery-orange microtomentose; 2 strong, reclinate parafrontal setae; ocellar setae 

1 strong pair, positioned at level of or anterior to anterior 

ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate postocellar seta; medial vertical 

seta strong, widely separated and convergent; lateral vertical seta long, strong and divergent; occiput rather wide, 

gray microtomentose, with 1 row of short dorsoclinate 

FIGURE 178. Distribution map for Trixoscelis litorea (Aldrich).
118 • smithsonian contributions to zoology

setulae in addition to several scattered setulae dorsally and 

ventrally, occiput extends below eye encroaching on genal 

area; antenna completely yellow; arista brown, with sparse 

hairs. Gena high, gena-to-eye ratio 0.53, orange microtomentose, bearing many scattered setulae in addition to a

pair of strong convergent oral vibrissae; face white; palpus 

yellow, clypeus small indistinct, gray.

Thorax: Mesonotum uniformly gray microtomentose, covered with many short setae, scutellum often 

yellowish medially. Acrostichal setae in 2 straight rows; 

apical scutellar setae more than twice length of scutellum. 

Anepisternum mostly bare except for one strong seta on 

posterodorsal corner along with 3–4 much smaller setulae 

in a cluster; katepisternum with 2 longer setae and 1–2 very 

short setulae along the posterodorsal edge. Wing yellowish 

hyaline with darker yellow veins. Halter white to yellow. 

Legs entirely yellow; fore femur with a row of longer setae 

along posterodorsal and posteroventral surfaces

Abdomen: Uniformly yellow microtomentose in

female and uniformly gray or yellow microtomentose in 

male, evenly setulose. Male terminalia (Figures 179–181): 

Epandrium (Figures 179, 181) in undissected specimens yellow; phallapodeme extremely long; surstylus (Figures 179, 

181) nearly entirely fused with epandrium, only a pair of 

very long setae remain on the medial surface of epandrium 

indicating where surstyli are as follows: pregonite (Figure 

180) fused with posterior hypandrium and with 3 posteriorly directed setae; postgonite (Figure 180) simple, long 

FIGURES 179–181. Structures of male terminalia of Trixoscelis melanderi Vockeroth: (179) epandrium, gonites, aedeagus, aedeagal apodeme, 

and hypandrium, lateral aspect; (180) aedeagus, aedeagal apodeme, gonites, and hypandrium, lateral aspect; (181) epandrium, posterior aspect. 

Scale = 0.1 mm.
number 637 • 119

lobe with several weak setulae distally; aedeagus extremely 

narrow simple pointed strap (Figures 179, 180). Female terminalia: Seventh tergite and sternite not completely fused; 

spermathecae spherical; eighth sternite lacking distinct 

lobes; hypoproct with two strong setae; epiproct lacking 

distinct pair of setae. 

Type Material. Melander described T. dimidiata from four females, of which one is here designated as 

the lectotype. The lectotype female is labeled “Riverside 

[33°58.8′N, 117°22.4′W] CAL[IFORNIA. Riverside:], 

5 May 1935, A. L. Melander/PARATYPE Trixoscelis 

dimidiata Melander [red]/A. L. Melander Collection 1961 

[white label with green stippling on right side]/Trixoscelis 

dimidiata Melander [white; handwritten]/LECTOTYPE ♀

Trixoscelis dimidiata Melander Foster & Mathis USNM 

[red]/USNM ENT 00118074 [plastic bar code label].” The 

lectotype is double mounted (pinned upright on a minuten 

glued in a brown cardboard square), is in excellent condition, and is deposited in the USNM. Paralectotypes are as 

follows:

UNITED STATES. California. Monterey: Lucia (near; 

36°01.2′N, 121°30′W), 17 Jun 1947, A. L. Melander 

(1♀; USNM). San Luis Obispo: Morro Bay (35°20.1′N, 

120°51.1′W), 27 July 1940, A. L. Melander (2♀; USNM).

Type Locality. United States. California. 

Riverside: Riverside (33°58.8′N, 117°22.4′W).

Other Specimens Examined. UNITED 

STATES. California. Los Angeles: Covina (34°05.4′N, 

117°53.4′W; on citrus), 7 Jun 1949, P. C. Ting (1♂; USNM); 

Santa Monica Mountains (34°12.6′N, 118°52.2′W), 3 Jul 

1950 (4♂; USNM). Monterey: Kirk Creek (35°59.3′N, 

121°29.8′W), 11 Aug 1969, B. Hocking (1♀; CNC). San 

Francisco: Lake Merced (37°43.3′N, 122°29.8′W), 3 May 

1968, P. H. Arnaud, Jr. (2♀; USNM); San Francisco Golden 

Gate Park (37°46.6′N, 122°28.8′W; Strybling Arboretum 

(Native Plants Area), 23 Sep 1980, P. H. Arnaud, Jr. (24♂; 

USNM). Ventura: Santa Paula (34°21.3′N, 119°03.6′W; 

on walnuts), 5 May 1949, H. H. Keifer, Schall (3♂, 4♀; 

CSCA, USNM).

Distribution (Figure 182). Nearctic: 

United States (California).

Remarks. The four male specimens from the 

Santa Monica Mountains are virtually identical to the lectotype in having a yellowish scutellum, and our concept of 

the species is based on these males and the lectotype. The 

other three female paralectotypes show a uniformly gray 

scutellum but match the lectotype in every other feature. 

The uniformly gray thorax with an often yellowish scutellum seems to be unique for the genus. The phallapodeme 

is unusually long for the genus and the anterior margin of 

the hypandrium is also unusually long. Last, the yellowish wings with even yellower veins are distinctive for this 

species as well.

Trixoscelis nuda (Coquillett)

FIGURES 170–171, 183–187

Leria nuda Coquillett, 1910:130.

Trixoscelis nuda. Aldrich, 1929:34 [generic combination; lectotype designation, discussion]. —Melander, 1952:48 [revision]. —Vockeroth, 

1965:818 [Nearctic catalog]. —Gill, 1968:7 [Neotropical catalog, distribution]. —Cole, 1969:434 [distribution, diagnosis].

Trixoscelis prima Hendel, 1911:43. —Melander, 1913b:296 [key to Nearctic 

species of Trixoscelis]. —Aldrich, 1929:34 [synonymy with T. nuda].

Diagnosis. Thorax uniformly gray microtomentose, subshiny, 2 irregular rows of acrostichal setae; 

wing hyaline; antenna yellow; gena moderately high, 

gena-to-eye ratio at least 0.33–0.43; male epandrium in 

undissected specimens concolorous with abdomen.

Description. Body length 2.20–3.66 mm.

Head (Figures 170, 171): Eye distinctly higher 

than wide; ocellar triangle light gray microtomentose; frons 

bare, yellow becoming brown laterad of ocellar triangle; 

parafrons whitish microtomentose; 2 strong, reclinate 

parafrontal setae; ocellar setae 1 strong pair, positioned at 

level of or anterior to anterior ocellus, 1 additional posterior pair of shorter, weaker ocellar setae; 1 short cruciate 

postocellar seta; medial vertical seta strong, widely separated and convergent; lateral vertical seta long, strong and 

divergent;occiput quite wide, gray microtomentose with 

2–3 variable length rows of short dorsoclinate setulae in 

addition to several scattered setae dorsally and ventrally; 

antenna entirely yellow, arista brown, with sparse hairs. 

Gena moderately high, gena-to-eye ratio 0.33–0.43, yellow 

microtomentose, many scattered, short setulae in addition

to a pair of strong convergent oral vibrissae; face yellow, 

palpus yellow, clypeus small indistinct, brown.

Thorax: Mesonotum uniformly gray microtomentose, sparsely covered with setae much shorter than the dorsocentral setae. Dorsocentral setae 5(2+3); acrostichal setae 

in 2 rows; apical scutellar setae clearly more than twice 

length of scutellum. Anepisternum mostly bare except for 

one strong seta on posterodorsal corner along with only 

3–4 much smaller setulae in a cluster; katepisternum with 

2 longer setae and several very short setulae along the posterodorsal edge in addition to a row of short setulae just 

anterior to the midline of the sclerite. Wing hyaline. Halter 

pale yellow to white. Legs entirely yellow, apical tarsomeres 
120 • smithsonian contributions to zoology

slightly darker; fore femur with a row of longer setae along 

posterodorsal and posteroventral surfaces

Abdomen: Uniformly gray to brownish microtomentose, evenly setulose. Male terminalia (Figures 

183–186): Epandrium (Figures 183, 184) in undissected 

specimens concolorous with remainder of abdomen; surstylus (Figure 183, 184) simple, lobate, partially fused to 

epandrium, appearing absent in some specimens; pregonite 

simple, with a posteriorly directed seta distally on ventral 

corner, with row of 4–5 weak posteroventrally directed 

setae along ventral margin; postgonite (Figures 185, 186) 

long, narrow anteriorly curved, bare lobe; distiphallus wide 

(Figures 183, 185, 186) and strongly sclerotized (sclerotization not depicted in illustration), triangular basally, 

extended in a long, narrow pointed strap distally. Female 

terminalia: Seventh tergite and sternite weakly fused; spermathecae conical; eighth sternite lacking distinct lobes; hypoproct with two strong setae; epiproct with a weak but 

distinct pair of setae. 

Type Material. Coquillett described L. nuda

from a type series of two females: one female from Claremont, California, and a second female from Santa Fe, 

New Mexico. Aldrich (1929) designated the syntype from 

Claremont as the “type” (= lectotype) and further stated 

that the syntype from New Mexico is conspecific with 

T. cinerea. An examination of the Santa Fe syntype shows 

that it is likely T. flavens but clearly is not T. cinerea. Because it is a female we are unable to determine its exact 

identification however. We also examined 37 (11♂, 26♀) 

other specimens from Claremont with identical labels as 

FIGURE 182. Distribution map for Trixoscelis melanderi Vockeroth.
number 637 • 121

the lectotype. We have dissected both a male and female 

and are confident of the identity of this species. The lectotype that was designated by Aldrich is a female and is 

labeled “Claremont Cal[ifornia] Baker/TypeNo. 13100, 

U.S.N.M.” [red, “13100” handwritten]/Leria nuda Coq. 

[handwritten on white paper label with black border and 

folded into thirds]/Trixoscelis nuda A. Coq. [handwritten 

on white paper label with black border]/LECTOTYPE ♂

Leria nuda Coquillett Des. Aldrich USNM [red].” The 

lectotype is pinned directly, is in good condition (missing 

the apex of the left wing and a small piece of the right 

wing; there is some green verdigris-like material on the 

dorsal and ventral portions where the pin pierces the 

specimen), and is deposited in the USNM (13100). The 

paralectotype is labeled “Ckll 3800 Sta F. July” [handwritten on white paper label]/“U.S.N.M. Acc 30623” [small 

white label with the number handwritten]/Paratype 13100 

U.S.N.M. [red “13100” handwritten]/Paratype of nuda 

FIGURES 183–186. Structures of male terminalia of Trixoscelis nuda (Coquillett) (California. Los Angeles: Claremont): (183) epandrium, surstylus, gonites, aedeagus, aedeagal apodeme, and hypandrium, lateral aspect; (184) epandrium and surstyli, posterior aspect; (185) gonites and 

hypandrium, lateral aspect; (186) hypandrium, aedeagus and gonites, ventral aspect. Scale = 0.1 mm.
122 • smithsonian contributions to zoology

Coq. [handwritten on white label].” According to Coquillett (1910), the locality data are interpreted as Santa Fe, 

New Mexico, and the collector is T. D. A. Cockerell.

Hendel (1911) described T. prima from a male and a 

female. Both specimens were collected in Claremont, California, which was incorrectly cited as “New-Hampshire” 

by Hendel. Although we have not examined these specimens, we are certain that they are from the same series 

as the 37 other specimens in the USNM that are also labeled “Claremont Cal[ifornia] Baker.” All 37 specimens 

are clearly T. nuda, and it is on this basis that we conclude 

that Hendel’s T. prima is a synonym of T. nuda, which was 

described earlier.

Type Locality. United States. California. Los 

Angeles: Claremont (34°05.8′N, 117°43.2′W).

Other Specimens Examined. MEXICO. 

Baja California. Rancho San Ignacio (26 km E Rosarito; 

32°20.9′N, 117°02.5′W), 26–27 Mar 1982, J. Slansky, 

M. S. Wasbauer (1♂; CSCA).

UNITED STATES. California. Kern: Bakersfield (32 

km NE, Cow Flat Creek; 35°30.1′N, 118°41.6′W; 500 

m), 25 Apr 2002, S. D. Gaimari (1♂; CSCA). Los Angeles: Catalina Island (33°23′N, 118°25′W), 18 Apr 1936, 

A. H. Sturtevant (1♂; USNM); Claremont (34°05.8′N, 

117°43.2′W), 25–29 Mar 1955, 1958, C. F. Baker, J. C. 

Hall, A. L. Melander, Metz (14♂, 25♀; USNM); Gorman (8 km SE; 34°47.5′N, 118°51.1′W), 30 Mar 1968, 

M. S. Wasbauer (1♂, 3♀; CSCA); Lancaster (34°41.9′N, 

118°08.2′W), 14 Mar 1935, A. L. Melander (1♂; USNM); 

Long Beach (33°46′N, 118°11.4′W), 29 Mar 1950, 

A. L. Melander (2♂; USNM); Mint Canyon (34°25.8′N, 

118°26.5′W), 28 Apr 1955, W. R. Richards (1♂, 4♀; 

CNC); Pacific Palisades (34°02.9′N, 118°31.6′W), 30 Apr 

1952 (1♂; USNM); Pasadena (34°08.9′N, 118°08.7′W), 

20 Feb 1929, A. H. Sturtevant (1♂; USNM); San Pedro 

(33°49.2′N, 118°17.5′W; string beans), 3 Apr 1944, C. G. 

Anderson (2♂, 1♀; CSCA, USNM); Solamint (Santa 

Clarita; 34°23.5′N, 118°32.5′W), 28 Apr 1955, W. R. 

M. Mason (15♂, 20♀; CNC); Tanbark Flats (34°12.2′N, 

117°45.6′W), 18 Jun 1956, H. W. Michalk (1♂; CSCA); 

Westwood Hills (34°02.8′N, 118°26.1′W), 5 May 1947 

(1♂, 3♀; USNM). Orange: Buena Park (33°52.1′N, 

117°59.9′W), 13 Apr 1961, D. H. Byers (1♂; CSCA); 

San Clemente (33°25.6′N, 117°36.7′W), 4 Feb 1947, 

A. L. Melander (1♂; USNM). Riverside: Andreas Canyon 

(33°45.7′N, 116°32.2′W), 26 Mar–10 Apr 1955, W. R. 

Richards (7♂; CNC); Aguanga (33°26.6′N, 116°51.9′W), 

6 Apr 1967, D. M. Wood (4♂, 2♀; CNC); Cabazon 

(33°55.1′N, 116°47.2′W), 31 Mar 1945, A. L. Melander 

(2♂, 1♀; USNM); Gavilan Hills (33°47.1′N, 117°22.2′W), 

11 Apr 1954, A. L. Melander (10♂, 13♀; USNM); Lake 

Mathews (33°50.6′N, 117°27.7′W), 9 Apr 1957, A. L. 

Melander (14♂, 9♀; USNM); Magnesium Spring Canyon 

(near Indio; 33°43.2′N, 116°13′W), A. L. Melander (1♂, 

2♀; USNM); Menifee Valley (hills on west end;39°39′N, 

117°13′W; 550 m), 9–28 Mar 1982, J. D. Pinto (28♂, 

22♀; DEBU); Palm Desert (33°43.3′N, 116°22.5′W), 

4 Apr 1955, W. R. Richards (3♂, 2♀; CNC); Palm Springs 

(33°49.8′N, 116°32.7′W), 15–26 Mar 1955, 1960, A. L. 

Melander, M. S. Wasbauer (2♂; CSCA, USNM); Pedley 

(33°58.5′N, 117°28.5′W), 25 Mar 1952, G. H. Sperry, 

J. L. Sperry (1♂; USNM); Rancho Mirage (33°44.4′N, 

116°24.8′W), 6 Apr 1955, W. R. M. Mason (8♂, 9♀; CNC); 

Riverside (33°58.8′N, 117°22.4′W; ex. oats), 19 Mar 

2002, E. Drake (6♂, 9♀; CSCA); Riverside (33°58.8′N, 

117°22.4′W), 09 Feb–11 Apr 1935, 1944, 1945, 1946, 

2002, E. Drake, A. L. Melander (18♂, 16♀; USNM); 

Riverside (33°58.8′N, 117°22.4′W), 11 Apr 1951, A. L. 

Melander (1♂; USNM), 15 Feb 1950 (2♂; USNM), 19 

Mar 1950 (2♂; USNM); Sheep Creek Canyon near Phelan 

(34°25′N, 117°36.4′W), 1 May 1946, A. L. Melander 

(1♂; USNM); Snow Creek, White Water (33°55.5′N, 

116°38.3′W; 460 m), 6–22 Apr 1955, W. R. Richards, 

W. R. M. Mason (4♂, 6♀; CNC); Tecate (32°34.6′N, 

116°37.7′W), 2 May 1966, R. Duke (4♂, 3♀; USNM); 

Temecula (33°29.6′N, 117°08.9′W), 29 Mar 1960, 

M. S. Wasbauer (3♂, 10♀; CSCA); Thermal (33°38.4′N, 

116°08.4′W), 8 Mar 1955, W. R. Richards (3♂, 1♀; CNC); 

Thousand Palms (33°48.7′N, 116°22.6′W), 12 Mar–27 

Apr 1955, W. R. Richards, W. R. M. Mason, J. E. H. 

Martin (24♂, 29♀; CNC); Thousand Palms, Willis Palms 

Oasis (33°49′N, 116°23.6′W), 25 Mar–5 Apr 1955, W. R. 

Richards, W. R. M. Mason (5♂, 4♀; CNC); White Water 

(33°55.5′N, 116°38.3′W), 17 Mar 1955, W. R. Richards 

(1♂, 3♀; CNC). Sacramento: Courtland (38°19.9′N, 

121°34.1′W; ex. alfalfa mustard), 4 May 1932, S. Lockwood (1♂; CSCA); Sacramento River Levee (38°36.3′N, 

121°33.3′W), 27 Mar 1969, R. R. Pinger, M. S. Wasbauer (2♂, 1♀; CSCA, USNM). San Bernardino: Adelanto 

(34°35′N, 117°24.6′W), 28 Apr 1949, A. L. Melander 

(1♂; USNM); Loma Linda (34°02.9′N, 117°15.7′W), 25 

Apr 1949, R. E. Ryckman (2♂, 1♀; USNM); TwentyNine Palms (32 km NE; 34°10′N, 115°57.3′W), 3 Apr 

1969, R. R. Pinger (1♂; USNM); Verdemont (34°11.6′N, 

117°22.1′W), 18 Feb 1958, A. L. Melander (2♂; USNM). 

Santa Barbara: Santa Cruz Island, between head of Alamos Canyon and Centinela (34°01′N, 119°48.5′W; 

sweeps of low vegetation near pines), 21 Mar 1982, J. T. 

Huber (20♂, 14♀; DEBU); Santa Cruz Island, Christi 

Beach (34°01.5′N, 119°52.5′W; pan traps), 10 Mar 1971, 
number 637 • 123

D. S. Horning (1♂, 1♀; CSCA); Santa Cruz Island, Christy 

Beach and Canyon (34°01.5′N, 119°52.4′W), 22 Mar 

1982, J. T. Huber (7♂, 15♀; DEBU). Santa Clara: Stanford University (37°25.6′N, 122°10.2′W), 23 May 1956, 

P. H. Arnaud, Jr. (6♂, 6♀; USNM). San Diego: Borrego, 

Tub Canyon (33°13.3′N, 116°20.1′W), 19 Apr 1949, 

G. H. Sperry, J. L. Sperry (1♂; USNM); Cardiff-by-the-Sea 

(33°01.3′N, 117°16.9′W), 21–26 Apr 1967, D. Davis (2♂, 

1♀; USNM); Cleveland National Forest, Boulder Oaks 

Camp (32°43.9′N, 116°29.1′W; 915 m), 3 Apr 1967, 

D. M. Wood (1♂; CNC); Cuyamaca Lake (32°59.4′N, 

116°35.2′W; 1400 m), 21 Apr 1955, W. R. Richards (1♂, 

2♀; CNC); Oceanside (33°12.4′N, 117°23.2′W; river 

margin), 13 Mar–4 Apr 1953, 2005, C. Gammon, W. N. 

Mathis, D. Mathis (2♂, 1♀; CSCA, USNM); Warner 

Springs (10 km SE; 33°16.9′N, 116°38′W; ex. Ranunculus), 27 Mar 1967, A. R. Gittens (5♂, 4♀; DEBU). San 

Luis Obispo: Cholame (35°43.4′N, 120°17.8′W), 23 Mar 

1947, P. H. Arnaud, Jr. (2♂; USNM); Nipomo (33°12.4′N, 

117°23.2′W; ex. pole peas), 28 Apr 1938, S. Lockwood 

(1♂; CSCA).

Washington. Island: Fort Casey (near; 48°09.8′N, 

122°40.7′W), 24 Jun 1944, P. D. Shenefelt (1♂; WSU).

Distribution (Figure 187). Nearctic: Mexico (Baja California), United States (California, 

Washington).

FIGURE 187. Distribution map for Trixoscelis nuda (Coquillett).

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Index to the Species 

of Trixoscelis

Figures in BOLD; Tables in Italic

albibasis, 7, 8, 8, 9, 10–11, 11, 12, 28, 46, 51

annetteae, 7, 8, 8, 94, 95–97, 95, 97, 98, 106

arnaudi, 7, 8, 8, 94, 97, 99, 99–100, 101

bajaensis, 7, 8, 8, 9, 11–13, 13, 14, 20

barberi, 7, 8, 8, 10, 16, 64–66, 66, 85

bifurcata, 7, 8, 8, 9, 14–17, 15, 16, 28

buccata, 7, 8, 8, 9, 17–19, 18, 19, 20, 21, 28

cinerea, 1, 2, 7, 8, 8, 58, 72, 74, 94, 98, 100–104, 102, 103, 120

claripennis, 2, 7, 8, 8, 9, 21, 64, 66–69, 68, 70, 74, 85

coloradensis, 7, 8, 8, 16, 94, 104, 104–105

costalis, 1, 2, 7, 8, 8, 21–23, 22, 23, 67

crepida, 7, 8, 8, 94, 105–106, 106, 107

deserta, 7, 8, 8, 9, 13, 20, 23–26, 25, 27, 28, 30, 41, 54, 59

desertensis, 7, 8, 8, 9, 13, 16, 26–27, 28, 29, 29–30

dimidiata, 117, 119

flava, 7, 8, 8, 94, 105, 106–109, 108, 109, 110, 111, 112

flavens, 7, 8, 8, 10, 64, 69–72, 71, 72, 73, 74, 103, 120

flavicornis, 7, 8, 8, 94, 105, 109–111, 110, 111, 112

flavida, 7, 8, 8, 9, 66, 69, 73, 74, 75, 76–85, 84, 92, 93

frontalis, 2, 5, 21, 74, 75, 83, 84, 85

fumipennis, 1, 2, 3, 5, 6, 7, 8, 8, 9–10, 28, 30–35, 31, 35, 40

gigapeza, 7, 8, 8, 10, 35–36, 36, 37, 39

granditarsa, 7, 8, 8, 10, 36–39, 38, 39, 40

kernensis, 7, 8, 8, 94, 111, 113, 113–114, 114

lagunaensis, 7, 8, 8, 10, 42, 62, 85, 86

litorea, 2, 7, 8, 8, 94, 115–117, 116, 117

melanderi, 7, 8, 8, 94, 117–119, 118, 120

mohavea, 2, 24, 25, 26
128 • smithsonian contributions to zoology

nevadensis, 7, 8, 8, 9, 39, 41, 42, 43, 60

nigripeza, 7, 8, 9, 41–43, 42, 44

nitidiventris, 6, 7, 8, 8, 9, 53, 64, 

86–89, 87, 88, 115

nuda, 2, 6, 7, 8, 8, 10, 72, 74, 89, 94, 

97, 99, 100, 103, 106, 109, 112, 

113, 114, 115, 116, 117, 119–122, 

121, 123

ornata, 7, 8, 9, 11, 28, 40, 43–46, 45,

47, 49, 51

plebs, 6, 7, 8, 8, 9, 64, 84, 88, 89–91, 

90, 91, 98

polita, 7, 8, 9, 45, 46–49, 48, 50, 58

prima, 1, 2, 100, 103, 119, 122

punctipennis, 7, 8, 9, 11, 46, 49–51, 51,

52, 58

pygochroa, 7, 8, 9, 51–54, 53, 55, 58, 59

sagulata, 2, 65, 66, 68, 69, 85

signifera, 7, 8, 9, 17, 58, 64, 91–94, 93

suffusa, 7, 8, 9, 30, 41, 54–57, 56, 57,

58, 59

triplex, 7, 8, 9, 59–61, 60, 61

tumida, 7, 8, 9, 10, 61–64, 63, 65, 73, 

78
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