Micropezidae Loew 1862
Creators: name: Lonsdale, Owen
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Micropezidae

description: Micropezidae Loew, 1862
(Figs 312–394, 421–422)
Type genus: Micropeza Meigen 1803: 276, in Loew (1862: 38) [see Sabrosky (1999) for discussion]. Type species of genus: Musca corrigiolata Linnaeus, 1767: 995, by monotypy.
Micropezidae is the most diverse family of Nerioidea with about 700 described species (Marshall, 2012) and it is certain that many more await discovered based on the productivity of recent revisionary work. Species occur globally except for Antarctica and New Zealand, with most diversity to be found in tropical regions. Five subfamilies are presently accepted within a monophyletic Micropezidae—Calycopteryginae, Calobatinae, Eurybatinae, Micropezinae and Taeniapterinae—reflecting the most recent classification of D.K. McAlpine (1975, 1998).
Micropezidae are relatively elongate and gracile, with long, narrow legs, and sometimes colourful patterning. While these aspects are modestly developed in Calobatinae, which is more typically acalyptrate in appearance, they can be exceptionally exaggerated in the other subfamilies, especially in the length of the mid and hind legs, which may far exceed the length of the body (see Marshall (2016: fig. 43, 2017: fig. 97)). A number of species mimic Hymenoptera, especially Ichneumonidae, and lineages in several subfamilies have independently converged on ant-mimicry (see Marshall (2016: figs 40, 41), sometimes including the development of a petiolate and sometimes nodular abdomen. The latter is well-illustrated in the apterous Australian Badisis ambulans McAlpine (Eurybatinae).
Wing loss is also seen in Calycopteryx moseleyi Eaton (Figs 328–333), the sole member of the subfamily Calycopteryginae, where vestiges of the wing and halter are still evident. This species, restricted to the Kergulen and Heard Islands in the south Indian Ocean, is adapted to life on windswept islands, and is atypically drab, robust and stout.
The more “modestly” proportioned subfamily Calobatinae (Figs 312–316) differs from other Micropezidae in lacking strong dorsal setae on the mid and hind tibiae, in having stronger apical tibial setae, more evenly distributed setae on the katepisternum, and wider abdominal sternites. The subfamily is Holarctic in distribution.
Members of the distinct subfamily Micropezinae (Figs 317–321) are exceptionally narrow, gracile and dark in appearance. The head is also elongate, cross-vein bm-m is absent, and there are no fronto-orbital setae. Most species occur in the diverse Micropeza, which is mostly Neotropical but also Holarctic in distribution, but three species are also known from Cryogonus Cresson, restricted to Chile and Argentina. The west Palaearctic Micropeza corrigiolata has been discovered in Canada (Hoebecke & Wheeler, 1994) and South Africa (Barraclough, 1996), where it was likely introduced via agricultural trade since the larvae are known to occur in the root nodules of commercially important legumes.
The subfamily Eurybatinae is almost entirely Oriental and Australian in distribution, but one monotypic genus is known from Costa Rica (Marshall, 2002), and one is known from Mauritius and Réunion (Barraclough, 1992a). One genus of Eurybatinae is so far known only from males, Anaeropsis Bigot; it is the only stalk-eyed nerioid and the only non-micropezine without fronto-orbitals (see D.K. McAlpine (1975)). The monophyly of the subfamily is “rather weakly supported” (D.K. McAlpine, 1998), and ongoing research suggests that its tribes Metopochetini (Fig. 327) and Eurybatini should be treated as separate subfamilies (Jackson et al., in manuscript; Yusof & Marshall, in manuscript).
Taeniapterinae (Figs 322–326) is the most diverse subfamily of Micropezidae in terms of both genera and species. It is found in all biogeographic regions with highest diversity in the Neotropics. The subfamily is characterized by a fan-like clustering of setae posteriorly on the katepisternum, sometimes anteriorly shifted ocelli, sometimes a laterally compressed epandrium, a lack of surstyli, elongate fore coxae (also Eurybatinae) and sometimes a pointed anal cell (also Eurybatinae) that can be exceptionaly long in some species (D.K. McAlpine, 1998).
Regional catalogues of Micropezidae are available in Steyskal (1965b) [Americas north of Mexico]; Aczél (1949c) [Neotropical Region]; Steyskal (1968a) [Americas south of USA]; Marshall et al. (2016) [Colombia]; Soós (1984a) [Palaearctic Region]; Steyskal (1980b) [Afrotropical Region]; Steyskal (1977c) [Oriental Region]; Evenhuis (1989a) [Australasia/Oceaniania]. The North American fauna has been treated or summarized by Cresson (1938), Merritt (1971, 1972), Merritt & James (1973), Merritt & Peterson (1976) and Steyskal (1987a). Treatments of the Palaearctic fauna have been provided by Czerny (1930a), Greve & Nielsen (1991), Roháček & Barták (1990) and Ozerov (1987). In the last few decades, work on the Afrotropical fauna include genus and regional revisions by Barraclough (1992b, 1993c, 1996) and Marshall (2014, 2017, 2019). Treatments of the Australasian fauna were provided by Steyskal (1947, 1952), who reviewed some species from the Solomon Islands and described Australasian specimens deposited in the USNM. Aczél (1959) treated the Micropezidae of Micronesia. D.K. McAlpine reclassified the family-level groups of Micropezidae and reviewed the Australasian Eurybatinae (D.K. McAlpine, 1975), and later revised the fauna of Australia (D.K. McAlpine, 1998). Li et al. (2015) revised the Oriental Cothornobata. Early works on the Neotropical fauna include Cresson (1930), Hennig (1934b, 1935a, b) and Aczél (1949b, 1951). Contemporary revisionary work of Neotropical taxa is being primarily developed by S.A. Marshall and colleagues: Marshall (2002, 2004 a, b, 2010, 2011, 2013, 2014, 2015, 2016), Marshall & Jackson (2014), Ferro & Marshall (2018).
Fossils of five species in four genera of Micropezidae are listed in Evenhuis (1997): Calobata rottensis (Statz) [compression fossil, Oligocene, Germany]; Micropeza prompta Meunier [Copal fossil, Tanzania, Pleistocene / Ho- locene]; Rainieria sp. [amber, Dominican Republic, Oligocene/Miocene]; Electrobata myrmecia Hennig [amber, Baltic Region, Eocene / Oligocene]; E. tertiaria (Meunier) [amber, Baltic Region, Eocene / Oligocene]. D.K. McAl- pine (1998) suggested that both named Electrobata species might be best treated within different genera, which would certainly seem warranted based on their divergence in chaetotaxy, venation and sclerite shape. Evenhuis (1997) further notes that other, possibly undescribed species are mentioned in the literature from Baltic amber, Chiapas amber and Sicilian amber, and a specimen of Micropezidae in Dominican amber is figured in Grimaldi & Engel (2005). An additional “ Electrobata spec.” from Baltic amber was examined in Hennig (1967). Tschirnhaus & Hoffeins (2009) also list additional taxa from Baltic amber that they did not formally describe, but included in a key to Baltic Amber Acalyptratae.
One fossil genus and species was previously recognized for Cypselosomatidae— Cypselosomatites succini Hennig. The species was described from Baltic amber by Hennig (1965), who considered it basal to the remainder of the family. D.K. McAlpine (1966) noted that the species more closely approached Micropezidae in morphology, but no reclassification was proposed until a later date when he formally treated it as Micropezidae (D.K. McAlpine, 1998).
Biology. Adults of Micropezidae are often encountered on horizontal surfaces such as low foliage and logs, usually in sunspots, and sometimes near moving or standing water, including temporary pools (Merritt & James, 1973; Roháček & Barták, 1990; Marshall, 2010, 2012). Many species occur at a variety of elevations, mostly lowlands, but some species and genera are found only at high-altitudes, including Neotropical Mesoconius (see Marshall (2015)). North temperate species mostly occur in moist wooded areas, but also meadows, marshes and grasses along water (Merritt & James, 1973; Roháček & Barták, 1990; Roháček, 2012b); Micropeza corrigiolata has been collected off of grass and vegetation in moist, shaded areas, and in meadows and fields containing legumes (Barraclough, 1996; Hoebeke & Wheeler, 1994). In Australia, species of Metopochetus were mostly collected in rainforests, similar to Australian Cothornobata and Crepidochetus, as well as on standing Eucalyptus trees and saplings (D.K. McAlpine, 1998). Mimegralla australica Hennig appears to prefer disturbed habitats (D.K. McAlpine, 1998). Neotropical species are known from numerous habitats, including rainforests, edges and disturbed habitats such as cacao plan- tations, but also native forests (Marshall, 2010, 2013). Some taxa appear to require pristine habitats that have had little to no disturbance, such as Mesoconius, which is particularly restricted in its habitat requirements (Marshall, 2010). South African taeniapterines occur in sunlit areas, open woodlands, disturbed areas including suburban areas or cultivated gardens, and cool, shaded, humid forests, sometimes at edges (Barraclough, 1996).
Adults can be locally abundant on carrion, artificial honeydew and decaying fruit (Barraclough, 1996; Marshall, 2010, 2012, 2013), but also on ripe or damaged fruit (Oosetrbrook, 1998). Mimegralla albimana Doleschall was considered an opportunistic feeder on a decomposing pig carcass (Chin et al., 2011). Many taxa are also very frequently found at mammal or bird dung, sometimes in large numbers (Merritt & James, 1973; Marshall, 2010, 2012), and small dung baits of are a reliable means of collection, although some taxa do not appear to be attracted to this substrate, including Tenthes Cresson, Metasphen Frey and some Grallipeza (Taeniapterinae) (Marshall, 2010, 2013). Feeding on insects is known in some adult Micropezidae, especially Calobatinae, which may be at least facultatively predaceous (Marshall, 2012), with observations of specimens feeding on aphids and small, mostly nematocerous Diptera (Colyer & Hammond, 1968). Taeniaptera lasciva (Fab.) is noted as being a predator on adult Diatraea saccharalis (Fab.), the sugarcane moth borer (Bennett & Alam, 1985).
Mimicry of Hymenoptera appears to be common among Micropezidae, modeling species of Formicidae, Ichneumonidae and sometimes Pompilidae (Marshall, 2010). While the benefits of ant-mimicry are well documented and known to have evolved independently at least 70 times (Mclver & Stonedahl, 1993), the relative benefits of parasitoid mimicry are yet to be determined, although it would appear to be sufficient given the number of presumed mimics, especially within Taeniapterinae. Many Ichneumonidae, including Ophioninae and Tryphoninae, are capable of stinging, with some being quite painful, and species of several subfamilies are known to release a pungent, possibly protective odour when disturbed (Quicke, 2013). These and other Ichneumonidae are also capable of using their ovipositor to keep distance from an enemy and may engage in aggressive behaviour such as biting. Mimics of Ichneumonidae have entirely to partially bright white fore tarsi and are typically found on foliage or usually horiozontal bark (Berg, 1947), waving one or both extended fore legs in front of them, with these legs having the movement and appearance of the model’s antennae (Hennig, 1935b; Barraclough, 1996; D.K. McAlpine, 1998; Marshall, 2010). Individuals of one of these mimics, Ptilosphen viriolatus Enderlein, were observed in “sleeping aggregations”, wherein sleeping individuals faced the petiole, and slowly and continuously waved their fore legs in a manner similar to that seen while awake (Ortiz, 2001). Barraclough (1996) noted this leg-waiving was sometimes seen between individuals of the same species, although the role of this behaviour and their sex was not determined.
Courtship behaviour appears to have an important role in reproduction. Behaviour of the ant mimic Cardiacephala arthriticus (Wiedemann) was recorded by Wheeler (1924) in detail, wherein a male on the top of a large leaf fended off rival males and engaged females to convince them to mate. Females appeared to chase away males until the males convinced them to mate by presenting regurgitated fluid as a gift while “dancing”. The provision of fluid gifts and other courtship activities continued until mating was completed. Marshall (2012) noted that the oral exchange of fluids is also common in Taeniaptera and photographed such a transfer between a pair of T. trivittata Macquart. Barraclough (1996) theorized that similar exchanges of nuptial gifts would be present in those Taeniapterinae with lateral swellings anteriorly in the male pleural membrane such as Mimegralla. He suggested that the swellings had a glandular function similar to that seen in Tephritidae, where the swollen structures were associated with trophallaxis during courtship. Conversely, the author noted an alternative interpretation by D.K. McAlpine, who thought that the swellings were instead “evaporative areas associated with the release of a pheromone”. Other components of taeniapterine copulatory behaviour may involve “kissing” behaviour, not necessarily associated with the exchange of nuptial gifts, along with “stilting and stroking” actions (Marshall, 2012). Female display to attract a mate was observed in the taeniapterine Ptilosphen tetrastigma (Schiner), where a white banded abdomen and positioning of banded white forelegs were used (Marshall, 2012).
Oviposition in wood has been recorded for a number of Taeniapterinae and Eurybatinae, where eggs may be laid in cracks or irregularities in the wood or bark surface, sometimes including the openings of beetle burrows (Marshall, 2012). A male Grammicomyia Bigot was observed on a patch of fallen wood that was suitable for oviposition, where he waited for a female to arrive while defending the patch from other males (Marshall, 2012).
Much remains to be discovered of micropezid larval life history, but individuals appear to be generalist saprophages in a variety of habitats, with a preference for moist, rotting plant matter, most often including wood (with a minority in roots), grass and fruit, but also dung. Calobatinae have been reared from heaps of decaying vegetation, including grass (Teskey, 1972; Ferrar, 1987), and Russian Calobatella petonella (L.), which is known to overwinter in the soil, was reared from sewage tanks and pig dung (Lobanov, 1960).
In Eurybatinae, Li et al. (2015) suggested that larval development in rotting wood was likely widespread, noting that females from five genera were observed ovipositing on that substrate, including taxa photographed by Marshall (2012). Larvae of the unusual Badisis ambulans develop at the bottom of the cup leaves of Cephalotus follicularis (the Albany pitcher plant) (Yeates, 1992; Marshall, 2012), but this host specialization appears to be atypical for the family (D.K. McAlpine 1998). The likely ant model of B. ambulans has been observed on the same host plant (D.K. McAlpine, 1998).
In Taeniapterinae, larvae are mostly known from varied rotting media, especially plants: decaying vegetative material for Mimegralla coeruleifrons (Hennig, 1936c); decaying sugar cane cuttings for Taeniaptera lasciva (Cresson, 1938); the surrounding pulp of Metroxylon sagu (true Sago palm) seeds for M. albimana striatosafciata (Berg, 1947); decaying fruit of Myrianthus arborea for M. gowdeyi (Frey) and the palm tree Borassus flabellifera for M. respondens (Walker) (Verbeke, 1951). Albuquerque (1972) was able to rear Scipopus belzebul (Schiner) under lab conditions from rotting banana and human feces. Rotten wood in trees, sometimes noticeably attacked by fungus, has served as substrate for numerous species: rotting Liriodendron tulipfera for Calobatina geometroides (Cresson) (Wallace, 1969); rotting wood of Erythrina caffra for Cephalosphen conifrons (Bigot) (Hennig, 1936c); standing, rotting Ulmus americana suffering fungal attack for Rainieria brunneipes (Cresson) (Steyskal, 1942); beneath the bark of dead trees for M. a. albimana (Bohart & Gressitt, 1951) and M. albimana striatosafciata (Enderlein) (Berg, 1947); dead banana wood for M. albimana galbula (Bohart & Gressitt, 1951), T. lasciva (Fab.), T. annulata (Fab.) and Plocoscelus conifer (Hendel) (Fischer, 1932). Adult occurrence of Rainieria calceata (Fallén) on fallen Fagus sp. (beech) was tentatively taken as an indicator of larval habitat by Chandler (1975a). Numerous species in other genera have also been observed ovipositing in a variety of decaying plant material, including wood, rotting stems and Typha stems (see Marshall (2010, 2012)).
Species of Mimegralla (Taeniapterinae) are also known to be primary invaders of live plants. Mimegralla coeruleifrons (Macquart) —otherwise known as the “rhizome fly”—attacks ginger (Zingiber officinale) (Steyskal, 1964) and turmeric (Curcuma longa), tunneling in the outer and inner regions of the rhizome (Ghorpade et al., 1988). The host plant experiences yellowing and drying of the leaves and the main shoot, and is opened to invasion by a number of disease-causing fungi and nematodes (Ghorpade et al., 1988). Steyskal (1964) noted that records cited by Hennig (1952a, b) on Curcuma sp. (wild arrowroot) may also be M. coeruleifrons, and that other larvae found in North America on intercepted ginger from China were possibly Mimegralla, perhaps M. albimana galbula (Osten Sacken).
In Micropezinae, the sometimes pestiferous Micropeza corrigiolata might breed in compost heaps (Chinery, 1986), but larvae are known to occur on live legumes, specifically, in the fresh root nodules of Pisum arvense L., Medicago sativa L. and Trifolium pratense L.; the nodule is hollowed out from the inside leaving an empty shell, after which the larva burrows 30 cm into the soil to overwinter (Müller, 1957).
Calycopteryx mosleyi (Calycopteryginae) eggs were found on and under leaves on Pringlea antiscorbutica R. Br. (“Kergulen cabbage”). Larvae were found mining shallow pits in the roots of the plant, and were recovered among numerous other substrates, including under stones, other vegetation including Azorella sp., and the soil un- der decomposing animal matter, including the carcass of a “sea elephant” (presumably the Southern elephant seal, Mirounga leonine (Linnaeus)); puparia were recovered from moss and rotting seaweed (Womersley, 1937). Ferrar (1987) suggested that this relatively broad diet may not necessarily include P. antiscorbutica, which is absent from one island upon which the fly occurs.
Immature stages. Most descriptions of immature stages of Micropezidae are listed in Ferrar (1987), with references to published data on Calobatinae, Micropezinae, Taeniapterinae and Calycopteryginae. Third instar larvae and puparia of Badisis ambulans (Eurybatinae) were additionally described by Yeates (1992). Marshall (2013) figured larvae of Grallipeza spinuliger (Cresson).
Adult Diagnosis. Medium to large-sized flies; very slender and long-legged, especially mid and hind legs, with the fore legs shorter (Figs 312–333). Body length 5.0–21.0mm. Colour variable, often with banded legs including white segments on fore tarsus; wing variable, clear to cloudy, often banded. Ocellar seta and vibrissa absent. Usually one or two posteriorly positioned dorsocentrals, sometimes zero or up to six. Anepisternal, postpronotal and lateral scutellar setae absent. Katepisternal seta present, positioned posteriorly, often duplicated, triplicated or multiplicated (Figs 323, 326). Mid and hind tibiae usually with linear dorsal series of setae (absent in Calobatinae and Calycopteryx). Antenna slightly elbowed with length of first flagellomere usually one to two times width. Scutellum generally small, rounded. Wing and halter rarely vestigial to absent (Calycopteryx (Fig. 330–331), Badisis); relatively narrow with alula and anal lobe reduced (Figs 421–422); veins R 4+5 and M 1 convergent apically, sometimes fused for short distance; costa unbroken; sc complete; anal cell with distal vein (CuA) straight. Males usually with forked process on sternite 5 (Fig. 336); phallus usually with complex “phallic bulb”, sometimes with terminal flagella(e). Female with segment 7 forming large oviscape within which terminal segments are telescoped (Fig. 319).
Adult Definition. Medium to large-sized flies; body length 5.0–21.0mm. Very slender and usually very longlegged, especially mid and hind legs (possibly far exceeding body length), with fore legs shorter (Figs 312–333); shorter-legged in some, including Calobatinae and apterous species. Colour variable, black to pale yellow, often conspicuously patterned with banded legs, including white segments on fore tarsus; sometimes with iridescence or pruinose to silvery tomentose pattern; wing variable, clear to cloudy, often banded. Abdominal membrane sometimes patterned with setulae and/or pigment, continuing pattern on sclerites. Mostly pruinose; often with shiny patches, mostly on head and pleuron.
Chaetotaxy: 0–1 inner vertical; 0–1 outer vertical; usually 1–3 fronto-orbitals, but sometimes 0 (Micropezinae, Anaeropsis) or as many as 6; 0–1 small ocellar; 0–1 postocellar (slightly divergent to convergent); vibrissa absent. 0 presutural intra-alar; 0 postpronotal; 1–2 notopeurals (only anterior sometimes reduced to absent); 2 postsutural supra-alar (0 Calycopteryx, 1 Badisis); 0 postsutural intra-alar, uncommonly 1 generally small seta; usually 1 or 2 dorsocentrals, uncommonly 0 or up to 6 extending onto presutural scutum; 0 acrostichal; 1 scutellar (apical only, but sometimes also with strong discal or marginal setulae); 0–1 proepisternal (small to large), but sometimes ventral margin above fore coxa instead with series of setae; 0 anepisternal, but sometimes with posteromedial scattering of enlarged setulae; at least 1–3 katepisternals (uncommonly 1), but few Eurybatinae with up to 5 setae arranged vertically, and all Taeniapterinae with many setae mostly arranged into one or two thick vertical “fans” and sometimes also with medial or posterior scattering of enlarged setulae. Sometimes 1 or more small “suprahumeral” setae (Marshall 2013) on anterior margin of scutum medial to postpronotum. Face and frons variably setulose. Anterior margin of clypeus with distinct setae in Hoplocheiloma Cresson. Prosternum setose or bare. Fore femur sometimes with two rows of strong ventral setae; mid and hind femora sometimes with one or more outstanding dorsal setae. Dorsal or ventral apical setae on tibiae inconspicuous if present, never much longer than setulae, more commonly with multiple setae along margin that may be displaced laterally but sometimes with single outstanding medial seta; apex of fore tibia uncommonly with ventral seta. Mid and hind tibiae sometimes (not Calobatinae or Calycopteryginae) with dorsal row of setae (Fig. 323) that may be duplicated, staggered or scattered.
Head. Antenna shallowly to strongly deflexed. Pedicel and scape small; pedicel sometimes with outer-dorsal notch. First flagellomere rounded, sometimes tapering apically; uncommonly shorter than wide, usually more elongate with length not more than twice width. Arista inserted subbasally (appearing more apical on shortened antenna of Calycopteryx); usually bare, pubescent or short to long plumose, sometimes with longer rays; rays usually shorter or absent distally. Eye usually large, rendering gena, postgena and parafacial very narrow when viewed in profile (not Calycopteryx). Orbital plate usually well-developed and wide, delimiting long orbital vitta; shining, silvery tomentose or pruinose, but if pruinose, then sometimes not distinguishable; width of vitta variable, sometimes tapering at one or both ends, or ending in a point anteriorly (i.e. orbital plates meeting), sometimes sunken or swollen medially; frons usually rounded, sometimes prominently so, but sometimes flattened or somewhat concave; anterior margin of frons sometimes raised and partially curled laterally; frons, dorsum of face and parafacial sometimes moderately to strongly projecting; vertex sometimes evident as an angle, but often broadly rounded, apparently displacing posterior region of frons onto back of head. Ocellar tubercle flat or rounded, positioned near vertex or shifted anteriorly, sometimes slightly past centre of frons. Marshall (2011) follows Cresson (1930) in dividing the posterolateral region of the frons into two sections; the lateral “paracephalon”, which bears the outer vertical seta, and the medial “epicephalon”, which bears the inner vertical seta. Lunule concealed to narrowly visible. Face soft, at least less sclerotized ventrally, with adjacent sclerotized margin of face and parafacial sometimes approximate or meeting medially, reducing softer medial section to narrow band or carina (similar to Megamerinidae); sclerotized dorsal region of face usually prominent to raised or subcarinate medially; face sometimes very short with buccal cavity extending dorsally towards ventrally angled frons (especially in ant-like species); antennal bases meeting medially or separated, sometimes divided by more than width of scape. Back of head shallowly rounded, sometimes narrowly produced to meet thorax, sometimes with bulge above foramen. Clypeus well-developed, sometimes recessed, sometimes very large, broad and prominent. Palpus narrow and cylindrical to broad and flattened, sometimes not much longer than wide.
Thorax. High, often narrow, notum shallowly to strongly rounded; anteroventral region around fore coxae sometimes recessed, and katepisternum and/or postsutural region sometimes bulging with posterior margin recessed. Transverse suture at or behind midpoint of scutum, mostly or entirely complete; presutural thorax sometimes pronounced, with anteromedial region of scutum long, bulging and sometimes overhanging pronotum, and with notopleuron elongate and pointed posterolaterally. Pronotum sometimes extended anteriorly to form narrow “neck”. Postpronotum various, either small and rounded, bulging, obliterated or narrow and elongate. Scutellum short, rounded, sometimes angled dorsally; reduced in apterous species. Subscutellum variable, usually moderately developed to narrow and linear or absent; sometimes swollen and bulging (some Eurybatinae), rarely conical and larger than scutellum as in Nothybidae (Nestima). Metanotum sometimes reduced (Micropezinae) or atrophied (Calycopteryx), usually well-developed and high with katatergite swollen; sometimes strongly swollen with conical protuberance in some Mesoconius. Precoxal bridge absent. Postmetacoxal bridge present in some Eurybatinae. Prosternum variable; sometimes divided into anterior presternum and posterior basisternum; base of prosternum (or basisternum) sometimes fused to anteromedial margin of katepisternum. Male metasternum sometimes with posteriorly directed process approximating ends of genital fork (some Calobatinae).
Wing. (Figs 421–422) Wing relatively narrow with alula and anal lobe reduced. Vein R 1 terminating proximal to end of Sc or further beyond. Vein R 2+3 sometimes relatively short. Veins R 4+5 and M 1 convergent apically, sometimes fused for short distance; costa unbroken; sc complete; anal cell with distal vein (CuA) straight, rarely slightly sinuate; CuA sometimes much longer than terminal section of CuA+CuP (some Taeniapterinae). Basal and anal cells sometimes bare in part. “Axillary fascicle” (comb of setae on upper margin of upper calypter particular to Micropezidae) usually present. Haltere well-developed to very slender and gracile with small knob. Wing and haltere uncommonly vestigial (Calycopteryx) to absent (Badisis).
Legs. Hind and mid femora sometimes with abrupt swelling. Hind femur sometimes flattened and grooved. Tibiae (usually hind, or mid and hind, less commonly also fore tibia) uncommonly flattened, sometimes conspicuously so, and with longitudinal groove for at least part of its length on one or both sides (some Eurybatini, Taeniapterinae); fore tibia grooved only in some Taeniapterinae. Fore tarsus sometimes much shorter than fore tibia; apical male fore tarsomeres uncommonly modified (eg. some Mesoconius); fourth tarsomere slightly to much shorter than fifth tarsomere.
Abdomen. Typically long and slender. Anterior two segments sometimes narrow and elongate, giving abdomen petiolate appearance; if petiolate, syntergite 1+2 sometimes also appearing “nodular”, similar to ants (eg. Badisis). Sternite 1 usually evidently subtriangular to trapezoidal with anterior margin widest (Fig. 352); sternites 2–4 sometimes narrow to linear with anterior margin of sternite 2 wider. Abdomen past segment 6 usually strongly downturned and sometimes conspicuously glabrous and smooth. Abdominal membrane sometimes patterned with setulae or pigment, reflecting pattern on sclerites; male lateral membrane at segment 2 or 2–3 (but rarely 4—see Marshall (2014)) sometimes with swollen or inflatable “pleural sac”; abdomen sometimes swollen ventromedially. Spiracles 1–6 in membrane, spiracle 7 enclosed (sometimes in membrane in males).
Male genitalia. (Figs 334–370) S5 with bifid “genital fork” (Figs 334, 336) that is sometimes reduced (eg. Calycopteryx; Fig. 367) or absent (eg. some Taeniapterinae and Micropezinae); fork sometimes with short basal stalk or weakly to entirely divided at base. S6 separate from S7; S6 sometimes with process that extends between arms of genital fork (some Calobatinae; Fig. 313); S6 sometimes simple and plate-like with shape subtriangular to trapezoidal (Fig. 352), but strongly modified in some species, with narrow, sclerotized apodeme anteriorly that continues as two or three thickened ribs along plate-like posterior section (Fig. 336). S7 and S8 often entirely or mostly bare, with anterior margin more heavily sclerotized; S8 broad, dorsal, partially fused to S7 anterolaterally, leaving a broad to inconspicuous suture or cleft between the two sclerites posteriorly; S7 left lateral, sometimes extending ventrally. Membrane extending anteriorly from S7 and S8 with one or two floating supernumerary sclerites (Fig. 335) that are folded internally (also found in Neriidae). Subepandrial sclerite setose ventrolaterally, more weakly sclerotized medially, sometimes divided into halves that are joined dorsally or entirely divided. Epandrium setose with apex shallowly constricted, sometimes with anterodorsal margin produced, sometimes narrow and elongate. Cerci well-developed, separate, setose. Surstylus shape variable, usually short; sometimes absent (Taeniapterinae; Figs 349–352). Hypandrium bare, narrow; arms fused to elongate phallic plate that may be variably divided into two bands (Figs 340, 353–354). Pregonite long, band-like, minutely setose (but see Marshall (2019)); base fused to inner ventromedial surface of hypandrium. Postgonite shorter, band-like, sometimes partially fused to pregonite; apex usually swollen and outwardly directed; sometimes asymmetrical (some Taeniapterinae). Phallapodeme long, rod-like with apex slightly to strongly enlarged; sometimes with paired ventromedial process weakly to completely fused to inner surface of hypandrium. Epiphallus absent. Basiphallus small, ring- or U-shaped; rarely enlarged. Distiphallus long, rod-like with basal shaft, “phallic bulb”, and sometimes one or two apical flagellae; dorsum of shaft sometimes membranous; venter sclerotized, usually plate-like and sometimes medially split into two parallel bands; phallic bulb usually complex, uncommonly absent (Marshall, 2017), sometimes elongate with apical swelling (see Marshall (2014: fig. 7)). Ejaculatory apodeme usually large and stout, with short stem and broad, fan-like blade; sometimes reduced (eg. Barraclough (1996: fig. 14), Marshall (2002)); sperm pump shallow, wide, ventrally sclerotized and sometimes lobate and/or minutely spinulose.
Female genitalia. (Figs 371–394) Female segment 7 forming large, heavily sclerotized oviscape that encloses telescoped terminal segments at rest; sometimes variably compressed, medially bent, or basally and/or apically swollen; suture between tergite and sternite sometimes evident as a vestige anteriorly and posteriorly. Spiracle 7 enclosed within fused S7 and T7 anteriorly, but partially exposed to weakly sclerotized region if suture present anteriorly. Membranous region between segments 7 and 8 narrow, elongate, minutely wrinkled longitudinally. S8–10 and T8–10 small, narrow, apically setose. Internal rod-like process produced from S10 reduced to absent. Cercus small, rounded, setose. Normally three spermathecae (solitary spermatheca on one duct, paired spermathecae apically branching from second duct); four spermathecae in at least some Micropezinae (Freidberg, 1984) and Taeniapterinae (S.A. Marshall, pers. comm.); McAlpine (1996) discussed Dufour’s (1851) finding of two spermathecae in Compsobata cothurnata (Panzer) [= Compsobata cibaria (L.)], but a female dissected for the present study showed three spermathecae. Spermathecae pigmented, surface usually with subtle to conspicuous wrinkles, pits or protuberances; shape variable, usually spherical to ovate; length uncommonly more than twice width, with one or both ends somewhat invaginated; solitary spermatheca sometimes atrophied or differing in shape. Two spermathecal ducts, apex sometimes pigmented; surface sometimes minutely wrinkled and/or ornamented with outgrowths. Ventral re- ceptacle highly variable, normally small, rounded to mushroom-shaped, sometimes pigmented or enlarged.
Variation—Cypselosomatites (incertae sedis in Nerioidea). Large-bodied species with relatively “typical” acalyptrate dimensions, but somewhat reminiscent of extant Micropezidae, with scutellum small, rounded and slightly upturned, with mid and hind legs slightly elongate (fore basitarsomere longer than half length of fore tibia) and mid coxae separated. Cypselosomatites similar to some Micropezidae as follows: two strong vertically arranged setae on katepisternum, two dorsocentrals, one outer and one inner vertical, no proepisternal, prosternum setose, fore tibia without apical setae; ocellar tubercle flat, near midpoint of frons; antennae separated by width of scape; postpronotum small and rounded; katatergite small. Differing from Micropezidae as follows: antenna porrect, arista bare; four fronto-orbitals, posterior seta displaced posteriorly, nearly level with inner vertical seta and as far from that seta as inner vertical is from outer vertical; ocellars small, proclinate; lateral scutellar present, nearly as long as small posterior intra-alar; legs without outstanding setae except for ventroapical seta on mid and hind tibiae (slightly offset from midline); alula and anal lobe well-developed; CuA rounded. Subcostal break absent in examined specimens, not present, as noted by Hennig (1965). Due to cloudiness in the amber surrounding the examined specimens, many regions are not visible, including the postcoxal region, the thoracic sternites, and most of the abdomen including the spiracles and male genitalia; it cannot be determined if a genital fork is present, but if it is present, then it is very small.
description: Published as part of Lonsdale, Owen, 2020, Family groups of Diopsoidea and Nerioidea (Diptera: Schizophora) - Definition, history and relationships, pp. 1-177 in Zootaxa 4735 (1) on pages 39-45, DOI: 10.11646/zootaxa.4735.1.1, http://zenodo.org/record/3670762