A revision of the Nearctic species of Liancalus Loew (Diptera, Dolichopodidae)

Abstract The genus Liancalus Loew is revised for the Nearctic Region. Seven species are documented from this region including two new species: Liancalus genualis Loew, Liancalus hydrophilus Aldrich, Liancalus limbatus Van Duzee, Liancalus pterodactyl sp. n., Liancalus querulus Osten Sacken, Liancalus similis Aldrich, and Liancalus sonorus sp. n. Lectotypes are designated for the following species: Liancalus genualis, Liancalus hydrophilus, Liancalus querulus, and Liancalus similis. The species are illustrated, a key to males and females is provided, and their distributions mapped. Adults of Liancalus are some of the largest species of Dolichopodidae and commonly occur on waterfalls and vertical seeps.


Introduction
Liancalus Loew, is a genus of long-legged flies in the subfamily Hydrophorinae containing 21 described species from all zoogeographical regions except Australasia and Oceania. Six species are known from the Palearctic Region, seven from the Nearctic Region, five from the Afrotropical Region, and three from the Oriental Region (Yang which must be rejected"]. Most subsequent workers have interpreted Loew's use of the name Liancalus to be a replacement name for Anoplomerus (e.g., Pollet et al. 2004;Yang et al. 2006), but Coquillett (1910) obviously considered it a new genus-group when he designated a type species. Loew clearly stated that this group already had a name -Anoplomerus -but that this name had to be rejected and that Liancalus is a suitable name for the group. This would indicate that Loew intended Liancalus as a replacement name.
Legs: Legs very long, slender, dark metallic green (Figs 8-9). Coxa I uniformly covered with white hairs on anterior surface; coxa II with white hairs on anterior surface and black ad seta near middle; coxa III with a black dorsal seta near middle (Fig.  1). Femur II and III with a slender preapical ad seta near 3/4. Tarsus I either with tarsomere 1 long and tarsomere 2 short (Figs 3A-E), or with tarsomere 1 short and tarsomere 2 long (Figs 3F-G).
Wing: Modified with dark brown markings and spots, sometimes enclosing a white apical spot and sometimes with lobes and setae . Calypter yellow with a fan of long, pale yellow setae. Halter pale yellow.
Abdomen: Cylindrical, elongate, and slightly broadened at apex (Fig. 2). T5 prolonged ventrally into two lateral flap-like projections that form a hood or pocket for the apex of the hypopygium. Hypopygium (Figs 10-12) nearly round, capping apex of abdomen. Phallus arched to rather sharply bent dorsally just before apex, with apical margin minutely serrate. Hypandrium rather broad, thin, arched anteriorly near apex with lateral lobe bearing setulae and a larger seta at or near apex. Epandrium with large, apical, thin, nearly transparent lobe that is hinged and can be raised or lowered dorsoventrally; at rest, this lobe sits against and covers the surstylus and base of cerci. Surstylus somewhat pointed, strongly sclerotized, directed medially, with large spatulate seta near apex. Cerci broad basally, with either very short (Figs 2E-F, 12) or very long filaments that project anteriorly below abdomen (Figs 2A-D, 8).
Female. Body length 5.0-9.0 mm, wing length 5.5-7.5 mm. Lacking typical male secondary sexual characters and similar to male except: face broader, nearly parallel-sided; palpi larger; fore tarsi unmodified; wings unmodified, but with diagnostic dark brown spots in most specimens (Fig. 16); abdomen shorter and somewhat flattened dorsoventrally.
Immatures. Larvae twelve segmented, cylindrical, truncate posteriorly and tapered anteriorly, opalescent with transparent cuticle; antenna with basal ring bearing sensilla; mouthparts dark brown to black, labrum large with pointed tip (sometimes hooked and/or with tooth-like projections), mandibular hook well developed; metacephalic rods enlarged at caudal tips, longer than tentorial arm. Pupa with prothoracic respiratory horns about 2 mm long, sharply pointed at tips; frontofacial sutures distinct, brown; abdominal segments 2-7 with rows of posteriorly-directed spines. Coccon elliptical, externally composed of sand grains and sometimes moss and mud, inner surface smooth; respiratory horn tips exposed. See Vaillant (1948), Corpus (1986) and Masunaga (2001) for illustrations and photographs of immature stages.
Remarks. Cerci of male specimens sometimes shrivel upon drying. In teneral specimens, the spots on the wings can be very faint which can render them, particularly females, difficult to identify.

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Wing with crossvein dm-cu meeting M 1 at nearly 45° angle; brown cloud in cell bm+dm not reaching crossvein dm-cu (Fig. 16G) ........ querulus Osten Sacken 13 Acrostichal setae stout, long (two-thirds to three-quarters size of dorsocentral setae); 3 rd costal sector (at apex of cell r 2+3 ) about 1.5 times length of 4 th costal sector (at apex of cell r 4+5 ) (Fig. 16D) (Fig. 3C), cerci long ( Fig. 2A), and wing as in Fig. 5A. This species is most similar to L. sonorus sp. n. but easily separated by the number of intra-alar seta (L. sonorus have 2), the male wings ( Fig. 5A-B), and distribution ( Fig. 13). Redescription. Male. Body length 7.0-9.0 mm, wing length 6.5-7.5 mm. Head: Face narrowed below antenna, slightly widening toward palpus, green or blue with silvergray pollen that is most dense along eyes and below frontoclypeal suture. Ommatidia near face slightly larger than remaining ommatidia. Vertex covered with silver pollen that is sparse medially revealing metallic green or blue ground color. Vertical setae on very small elevation; ocellar tubercle prominent with 2 large setae (slightly larger than vertical setae); with 2 postocellar setae which are two-thirds length ocellar setae; postocular setae approximately one-third size of vertical setae with about dorsal one-half black (approximately 12 black setae), ventral half (approximately 15 setae) white and more slender and slightly longer than black postocular setae. Ventral postcranial hairs (beard) rather sparse, wholly white. Palpus black, covered with moderately dense silver pollen and long, dense, dark brown to black setae on basal half. Antenna black, first flagellomere about as long as wide, broadly pointed apically, arista inserted near midpoint of dorsal edge.
Thorax: Scutum green to green-blue with moderately dense silver-gray pollen, with large red-bronze stripes between dorsocentral setae, and along intra-alar setae; medial stripe metallic pink; posterior slope of scutum bronze with lateral blue-green spots; scutellum bronze, with sparse silver pollen; notopleuron and postpronotum covered with silver pollen, often with some blue-green reflections; scutum with acrostichal setae absent (sometimes with a few small hairs on anterior slope of scutum); 6 dorsocentral setae, 2 notopleural setae, 1-2 strong, black postpronotal setae (often a few smaller white hairs), 1 presutural intra-alar seta (the posterior-most seta near transverse suture missing but with remnant dark spot where this seta inserted in other Liancalus -similar to small darkened area surrounding insertion of other setae on dorsum), 1 presutural seta, 2 postsutural supra-alar setae, and 1 postalar seta per side; scutellum with 6 large marginal setae (3 per side), no additional hairs; proepisternum with 1 dorsal and 1 ventral tuft of white hairs. Pleura metallic bronze-green, covered with dense silver-gray pollen, without setae or hairs.
Legs: Legs concolorous with pleura, but with distinctly less silver-gray pollen, femoral 'knees' orange ( Fig. 2A). Coxa I uniformly covered with white hairs on anterior surface (length of hairs subequal to width of coxa I), with a few black, slender setae at apex. Coxa II with a few white hairs anteriorly, a few white setae near apex, and a black ad seta just beyond 1/2. Coxa III with a few short, white hairs on anterior surface and a black dorsal seta near 1/2. Femur I with sparse, short, white hairs av to pv on basal half (length < half width of femur). Femur II with row of short (≤ width of femur) posterior to pv setae on distal half, those near to just beyond middle of femur white, longest and becoming black and shorter apically. Femur III with some white hairs (length ≤ width of femur) on dorsal and posterior surface at base. Tarsus I(1) long, as long as remaining tarsomeres combined (Fig. 3C). Tarsus I(2) very short, about as long as wide, with ventral row of setae/setulae (Fig. 3C). Ratios of tibia:tarsomeres for leg I: 18-9-1-4-3-2; for leg II: 28-25-11-4-2-2; for leg  Wing (Fig. 5A): Hyaline, with a longitudinal spurious vein between R 4+5 and M 1 that is arched on apical third of wing and terminates near midpoint of a circular, translucent, apical spot that is white in certain lights; this spot enclosed within a brown, apical cloud that extends anteriorly along costa to R 1 ; some light clouding also evident narrowly along R 4+5 on apical one-quarter of wing. Wing margin excavated posterior to M 1 ; with short, broad lobe between M 1 and CuA 1 . Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow.
Abdomen: Cylindrical, elongate, rather blunt at apex ( Fig. 2A); T1 metallic green with dense silver pollen laterally becoming less dense dorsally, with bronze along posterior edge and occasionally with a diffuse bronze stripe dorsally. T2-T4 blue-green with dense silver pollen on basal one-half to two-thirds, with apical one-third to one-half bronze. T5 dark bronze with metallic green reflections and sparse silver pollen. T6 dark bronze with blue-green reflections and with dense silver pollen. T1-T3 with yellowish hair laterally, longest on T1 and T2, without black hairs or setae. Sternites bronze with dense silver-gray pollen. S1 bare except for lateral small tuft of yellow hairs at extreme base. S2 and S3 with sparse yellow hairs. S4 mostly bare. Hypopygium (Fig. 10A): cercus very long, slender, cylindrical, with long pale yellow dorsal and ventral setae ( Fig. 2A).
Female. Body length 6.0-7.5 mm, wing length 6.0-7.0 mm. Similar to male except for face wider, dark violet-green covered with moderate to dense brown pollen; palpus black with silver pollen apically, dense golden-brown pollen basally, and black setae. Femur II posteriorly to pv with row of short (< half width of femur) hairs on apical half, those near middle white and becoming black apically. Wing (Fig. 16B) hyaline, with three diffuse brown clouds: largest one in cells r 4+5 and bm+dm and crossing M 1 near midpoint of wing, one on M 1 beyond crossvein dm-cu, and smallest one on R 4+5 at apex of wing.
Remarks. Loew reported types from "Middle States"; a hand-written label on one of the paralectotypes collected by Loew appears to be "KY". Adults of this species have been frequently found in caves, e.g., in Arkansas ( Barnes et al. 2009), Indiana (Banta 1907), Georgia (Reeves et al. 2000), Kentucky and Minnesota (see material examined).
Distribution. This is the only species of Liancalus known to occur in eastern North America (Fig. 13).   Diagnosis. This is one of two Nearctic species in which males have setae on the wing margin (Fig. 4). Males can be distinguished by the relatively short, rounded lobe between wing veins M 1 and CuA 1 (Fig. 4B), and by the long cerci with evenly spaced, long setae along their full-length (Fig. 8).
Redescription. Male. Body length 8.0-10.5 mm, wing length 6.5-8.0 mm. Habitus (Fig. 8). Head: Face rather broad, widening toward palpus, metallic green above frontoclypeal suture, covered with dense silver pollen below suture. Vertex covered with silver pollen that is often sparser medially revealing metallic green-blue ground color. Vertical setae on very small elevation; ocellar tubercle prominent with 2 large setae (slightly larger than vertical setae); with 2 postocellar setae which are two-thirds length ocellar setae; postocular setae approximately one-half size of vertical setae with about dorsal one-half of postocular setae black (approximately 15 black setae), ventral half (approximately 10 setae) white and more slender and slightly longer than black postocular setae. Ventral postcranial hairs (beard) rather sparse, usually wholly white (sometimes dorsal-most 1-3 hairs brown to black). Palpus black, covered with moderately dense silver pollen apically, golden brown pollen at base, with long, black setae on basal two-thirds. Antenna black, first flagellomere about as long as wide, slightly pointed apically, arista inserted near midpoint of dorsal edge.
Legs: Legs concolorous with pleura, but with slightly less silver-gray pollen, femoral 'knees' very narrowly orange. Coxa I uniformly covered with white hairs on anterior surface (length of hairs subequal to width of coxa I), with a couple to few black, slender setae at apex. Coxa II with scattered white hairs anteriorly, a few white and black setae near apex, and a black ad seta just beyond 1/2. Coxa III with a few short, white hairs on anterior surface and a black dorsal seta near 1/2. Femur I with row of black, pd setae on apical half (length ≤ half width of femur). Femur II with row of posterior setae on distal half (length ≤ width of femur), those near to just beyond middle of femur longest, white, and becoming black and shorter apically. Femur III with scattered white hairs (length ≤ width of femur) dorsally at base. Tarsus I(2) very short, about as long as wide, with ventral row of setae/setulae (Fig. 3B). Ratios of tibia:tarsomeres for leg I: 17-7-2-5-3-2; for leg II: 24-20-8-4-2-2; for leg III: 35-17-13-4-2-2.
Wing (Fig. 4B): Hyaline, with a longitudinal spurious vein immediately above M 1 that ends near junction of M 1 with dm-cu and usually two small brown clouds just beyond junction of dm-cu and CuA 1 (these spots sometimes faint); apical portion of membrane between R 4+5 and M 1 with a small, narrow, translucent, area that is white in certain lights and enclosed within a small, brown cloud. Fourth costal sector (between R 4+5 and M 1 ) flattened with a cluster of 3-6 black setae at apex of M 1 that are usually fused apically; wing margin between M 1 and CuA 1 with a rather short (length subequal to width), broad lobe bearing several black setae at apex that are usually fused apically. Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow.
Abdomen: Cylindrical, elongate, rather blunt at apex (Fig. 8); T1 metallic green with dense silver pollen laterally becoming less dense dorsally, with bronze along posterior edge and occasionally with a diffuse bronze stripe dorsally. T2-T4 green-blue with dense silver pollen on basal one-half to two-thirds, with apical one-third to one-half bronze; T2 usually bronze dorsally at base. T5 dark bronze with metallic green reflections and sparse silver pollen. T6 dark bronze with blue-green reflections and dense silver pollen. T1-T3 with wholly to nearly wholly yellowish hair laterally, longest on T1 and T2. Sternites bronze with dense silver-gray pollen. S1 bare except for lateral small tuft of yellow hairs at extreme base. S2 and S3 with sparse yellow hairs. S4 mostly bare. Hypopygium (Fig. 11B): cercus very long, as long or longer than abdomen, slender, cylindrical, with very long, evenly-spaced, pale yellow setae along full-length ventrally (Fig. 8), with some hairs crinkly on apical half.
Female. Body length 6.0-8.0 mm, wing length 6.0-7.0 mm. Similar to male except for face wider, dark metallic green to violet covered with sparse to moderately dense brown pollen; palpus black with silver pollen along margins and dense brown pollen basally, and black setae. Femur I with pd row of black setae on apical half (longest subequal to width of femur) and very sparse, very short white hairs on posterior and ventral surface. Femur II posteriorly to pd with row of short (length ≤ width of femur) hairs which are white on basal half and black on apical half. Wing (Fig. 16C) hyaline, with a rather large, diffuse, faint brown cloud in cells r 4+5 and bm+dm and crossing M 1 just beyond midpoint of wing; usually with some indistinct brown clouding along wing margin between R 1 and M 1 .
Remarks. Aldrich (1893) described the habits of this species at the type locality near Custer, SD. On page 570, Aldrich writes, "From several seams in the rock there is a gentle flow of almost ice-cold water, which covers a considerable area of vertical rock in a thin sheet. Standing in this icy water were my flies!" Similarly, Van Duzee (1917: 127) wrote, "I took a single male…resting on rocks over which water was trickling in South Cheyenne Canon [sic]".
Distribution. This species is confined to interior western North America (Fig. 14A).  Diagnosis. Males of this species have long cerci, wing without marginal setae but with a distinct marginal lobe between veins M 1 and CuA 1 , and with crossvein dm-cu relatively straight (Fig. 5C). Female wing as in Fig. 16D.
Redescription. Male. Body length 8.0-9.0 mm, wing length 6.5-7.5 mm. Head: Face narrow, slightly widening toward palpus, metallic green to bronze with sparse to moderately dense silver pollen. Vertex covered with silver pollen mostly hiding metallic green to blue ground color. Vertical setae on very small elevation; ocellar tubercle prominent with 2 large setae (subequal in size to vertical setae); with 2 postocellar setae which are one-half to two-thirds size of ocellar setae; postocular setae approximately one-half size of vertical setae with about dorsal one-half of postocular setae black (approximately 15 black setae), ventral half (approximately 10 setae) white and more slender and slightly longer than black postocular setae. Ventral postcranial hairs (beard) rather sparse, usually wholly white but rarely with 1-3 brown to black setae. Palpus relatively small, black, covered with sparse silver pollen and scattered yellow to yellow-brown hairs. Antenna black, first flagellomere about as long as wide, rounded apically, arista inserted near midpoint of dorsal edge.
Legs: Legs concolorous with pleura, but with slightly less silver-gray pollen, femoral 'knees' very narrowly orange. Coxa I uniformly covered with white hairs on anterior surface (length of hairs subequal to width of coxa I), with a couple black, slender setae near apex. Coxa II with scattered white hairs anteriorly, a few white and black setae near apex, and a black ad seta just beyond 1/2. Coxa III with a few short, white hairs on anterior surface and a black dorsal seta near 1/2. Femur I with row of short, black, pd setae on apical half (length ≤ half width of femur) and scattered, short, white hairs near base. Femur II with row of posterior hairs/setae (length ≤ width of femur), those on basal half white (longest near to just beyond middle of femur) and becoming black and shorter apically. Femur III with white hairs (length subequal to width of femur) dorsally to posteriorly at base. Tarsus I(2) very short, about as long as wide, with ventral row of setae/setulae (Fig. 3D). Ratios of tibia:tarsomeres for leg I: 16-8-2-4-3-2; for leg II: 26-20-8-4-2-2; for leg III: 37-20-17-6-2-2.
Wing (Fig. 5C): Hyaline, infuscated on anterior third, especially between R 2+3 and R 4+5 (mostly along veins apically); with a longitudinal spurious vein between R 4+5 and M 1 that is arched anteriorly near 2/3 of wing and terminates near midpoint of a semicircular, translucent, area that is white in certain lights and enclosed within a small, brown cloud; with a diffuse brown spot just above spurious vein at arch and small brown spot on CuA 1 near dm-cu. Apex of wing shallowly excavated at M 1 , with a broad, blunt, apically-pointed lobe between M 1 and CuA 1 , this lobe without setae. Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow.
Abdomen: Cylindrical, elongate, blunt at apex (Fig. 2C); T1 metallic green with dense silver pollen laterally becoming somewhat less dense dorsally. T2-T4 blue-green with dense silver pollen basally, bronze apically. T5 dark bronze with metallic green reflections and sparse silver pollen. T6 dark bronze with blue-green reflections and with dense silver pollen. T1-T3 with yellowish hair laterally, longest on T1 and T2, without black hairs or setae. Sternites bronze with dense silver-gray pollen. S1 bare except for lateral small tuft of yellow hairs at extreme base. S2 and S3 with sparse yellow hairs. S4 mostly bare. Hypopygium (Fig. 10C): cercus very long (as long as abdomen in unshriveled specimens), slender, cylindrical, with yellow hairs that are longest medially (Fig. 2C).
Female. Body length 7.0-8.0 mm, wing length 6.5-7.5 mm. Similar to male except for face twice as wide, dark green to violet obscured by moderate to dense brown pollen; palpus larger, black with silver pollen apically, with dense golden-brown pollen in middle at base, and black setae. Acrostichal setae large, stout, two-thirds to threequarters size of dorsocentral setae. Femur I with pd row of black setae on apical half (longest subequal to half width of femur) and sparse, very short white hairs on posterior and ventral surface. Femur II posteriorly with row of white hairs/setae on basal half to two-thirds (longest at base and just beyond middle) and black setae on apical half to one-third (longest of these posterior hairs/setae subequal to width of femur). Wing (Fig. 16D) hyaline, with three to four diffuse brown clouds: one in cells r 4+5 and bm+dm near midpoint of wing (this often appears like two 'spots' but actually connected by sometimes light brown clouding), one light brown cloud on M 1 beyond crossvein dm-cu, and usually with very small light brown clouding on R 4+5 at apex of wing; sometimes a small brown cloud is evident on CuA 1 .
Remarks. The type specimens were collected by Van Duzee (1917: 128) "at Berkeley, California, May 8th, on a wall of rock in a little canyon; the wall was covered with watersoaked moss". Specimens have commonly been collected on or near beaches and sea cliffs.
Copulation of this species was described by Peter Dyte (in litt. to Richard Hurley, 1988): "A pair of Liancalus limbatus V.D. were seen in copula on a seepage at Wreck Beach, Vancouver, B.C., Canada, on 5.vii.1988, at 16.18 hrs. They were captured by placing a 3×1 in[ch] tube over them and they remained in copula in the tube until 17.20 hrs...All her tarsi and his mid and hind tarsi were on the substrate, but his foretarsi were held against the sides of her third abdominal segment with their apices projecting slightly below her abdomen. Thus the modified second segment of his foretarsus would have been touching her abdomen, though the separate tarsal segments could not be distinguished with the hand lens available. His long genital lamellae pointed forwards below the female abdomen but not touching it".

Liancalus pterodactyl
Description. Male. Body length 9.0-12.0 mm, wing length 7.5-8.5 mm. Head: Face nearly parallel-sided on dorsal half, widening toward clypeus; frontoclypeal suture near mid-face, distinct; eyes with short hairs between facets; face green-bronze (more green immediately below antenna) with silver pollen most noticeable along eyes and on ventral half of face; ommatidia essentially the same size throughout. Vertex concolorous with face, usually with dense silver pollen. Vertical setae on small elevation; ocellar tubercle prominent with 2 large setae (subequal in size to vertical setae); with 2 postocellar setae which are two-thirds length ocellar setae; postocular setae approximately half length of vertical setae with dorsal two-thirds of postocular setae black (approximately 20 black setae), ventral third (approximately 10 setae) white and more slender and slightly longer than other postocular setae. Ventral postcranial hairs (beard) abundant, white with dorsal third to one-quarter black. Palpus black, covered with silver pollen and sparse black hairs. Antenna (Fig. 1) black, first flagellomere about as long as wide, rounded apically, arista inserted near midpoint of dorsal edge.
Legs: Legs concolorous with pleura. Coxa I (Fig. 1) uniformly covered with white, slender hairs on anterior surface (length of hairs subequal to width of coxa I), with a few black, slender setae at apex. Coxa II with white hairs anteriorly, a couple black setae near apex, and a black ad seta just beyond 1/2. Coxa III with scattered white hairs and a black dorsal seta near 1/2. Femur I with sparse white hairs on ventral surface (length ≤ width of femur). Femur II with row of short (≤ width of femur) posterior to pv setae on distal half, those near middle of femur white, longest and becoming black and shorter apically; with a row of very short black ad setae preceding usual preapical seta. Femur III with scattered white hairs (length ≤ width of femur) on dorsal and posterior surface at base. Tarsus I(2) short (length subequal to width), slightly thickened, with ventral brush of setulae (Fig. 3A). Ratios of tibia:tarsomeres for leg I: 18-7-2-5-3-2; for leg II: 26-22-7-4-2-2; for leg III: 38-17-13-4-2-2.
Wing (Figs 4A, 7): Hyaline, with light brown clouding between R 2+3 and R 4+5 apically, most distinct along veins; with a longitudinal spurious vein immediately above M 1 that ends near junction of M 1 with dm-cu; apical part of membrane between R 4+5 and M 1 with a narrow, translucent area that is white in certain lights and enclosed within a small, brown cloud (Fig. 7). Fourth costal sector (between R 4+5 and M 1 ) flattened with a cluster of 3-4 long, black setae at apex of M 1 that are usually fused apically; wing margin between M 1 and CuA 1 with a long (length > 3× width), slender, finger-like projection bearing several black setae at apex. Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow (Fig. 1).
Abdomen: Cylindrical, elongate (Fig. 2D); T1 metallic blue-green, covered with dense silver pollen. T2-T4 mostly metallic blue-green with silver pollen, with apical one-third bronze, usually bronze dorsally at base. T5 dark bronze with metallic green dorsally and sparse silver pollen. T6 dark metallic blue-green with sparse to moderate silver pollen. T1-T3 with long, white hair laterally, longest on T1 and T2. Sternites bronze with sparse silver-gray pollen. S1 bare except for lateral tuft of white hairs at extreme base. S2 and S3 with sparse long, white hairs. S4 mostly bare. Hypopygium (Fig. 11A): cerci as long or longer then abdomen, slender, cylindrical, with pale yellow setae on ventral surface that are most dense and longest on apical half (Fig. 2D).
Female. Body length 7.5-9.0 mm, wing length 7.0-7.5 mm. Similar to male except for face wider; palpus covered with golden brown pollen, with denser, black setae. Femur I with pd row of black setae/hairs and relatively long (subequal to width of femur), white hairs on ventral and posterior surface. Femur II with pale hair on posterior surface extending nearly to base; tarsus I(2) normal, not unusually short or thickened. Wing (Fig. 16A) hyaline, of normal shape; with diffuse brown clouding immediately above M 1 before junction with dm-cu, this clouding often continuing posteriorly into cell bm+dm.
Etymology. The epithet, a noun in apposition, is in reference to the large size of this species -reminiscent of the large pterosaurs from the Jurassic; and the Greek pteron "wing" + daktylos "finger" in reference to the finger-like lobe on the wing (Fig. 4A).
Remarks. This is perhaps the largest species of Dolichopodidae, at least in terms of body length.
Distribution. This species occurs in the Northern Rocky Mountains of U.S. and neighboring Canada; one male was collected in the Trinity Alps of northern California (Fig. 13).
Type Diagnosis. This species is most similar to L. similis: males of both have tarsus I with tarsomere 2 long (Fig. 3F-G), wings with apical brown clouding (Fig. 6), and very short cerci (Fig. 2E-F), but L. querulus males have a smaller, semicircular brown cloud near wing apex and no black speck in cell m (Fig. 6A). Female wing with three distinct brown spots and with crossvein dm-cu meeting M 1 at nearly 45° angle (Fig. 16G).
Redescription. Male. Body length 6.5-8.0 mm, wing length 6.0-7.5 mm. Head: Face rather broad, uniformly covered with dense silver pollen. Ommatidia near face slightly larger than remaining ommatidia. Vertex covered with dense silver pollen, often with some metallic green or blue color near middle. Vertical setae on very small elevation; ocellar tubercle prominent with 2 large setae (subequal in size to vertical setae); with 2 postocellar setae which are three-quarters length ocellar setae; postocular setae slightly less than one-half length of vertical setae with dorsal one-third of postocular setae black (approximately 10 black setae), ventral two-thirds (approximately 15 setae) white and more slender and slightly longer than black postocular setae. Ventral postcranial hairs (beard) rather sparse, wholly white. Palpus black, covered with sparse to moderately dense silver pollen and sparse black hairs. Antenna black, first   flagellomere about as long as wide, broadly pointed apically, arista inserted just beyond midpoint of dorsal edge.
Legs: Legs concolorous with pleura, but less silver-gray pollen, femoral 'knees' narrowly orange. Coxa I uniformly covered with white hairs on anterior surface (length of hairs subequal to width of coxa I), with a few black, slender setae at apex. Coxa II with a few white hairs anteriorly, a couple white setae near apex, and a black ad seta just beyond 1/2. Coxa III with a few white hairs and a black dorsal seta near 1/2. Femur I and II with short, white hairs posteriorly to pv on basal half (length < half width of femur). Femur III with some short white hairs (length ≤ width of femur) on dorsal and posterior surface at base. Tarsus I(1) short, approximately one-third length of tarsus I(2) (Fig. 3F); tarsus I(2) long, flattened ventrally and covered with dense setulae fulllength; tarsus I(3) slightly thickened near or just beyond middle (Fig. 3F); tarsus I(3-4) with black, felt-like setulae on pv surface. Ratios of tibia:tarsomeres for leg I: 11-3-8-3-2-2; for leg  Wing (Fig. 6A): Hyaline, with semicircular brown cloud near apex (clouding very faint in a few specimens). Wing relatively slender, rounded at apex, without outstanding hairs or setae. Veins R 4+5 and M 1 closely approximated and nearly parallel at apex of wing. Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow.
Abdomen: Cylindrical, elongate, slightly enlarged and rather blunt at apex (Fig.  2F); T1 metallic green-blue, with dense silver pollen laterally becoming less dense dorsally, with bronze along posterior edge and usually a narrow bronze stripe dorsally. T2-T4 bronze with large lateral blue-green spots covered with dense silver pollen. T5 dark bronze with metallic green reflections and sparse silver pollen. T6 bronze with blue-green reflections and with moderately dense silver pollen. T1-T3 with white hair laterally, longest on T1 and T2. Sternites bronze with silver-gray pollen. S1 bare except for lateral small tuft of white hairs at extreme base. S2 and S3 with sparse white hairs. S4 mostly bare. Hypopygium (Fig. 12A): cerci small, lacking long tubular filaments of other species, but with minute papilla where filaments originate in other species.
Female. Body length 5.0-7.5 mm, wing length 5.5-7.0 mm. Similar to male except for face slightly wider, dark blue-green covered with moderate golden-brown pollen that is most dense along eyes; palpus black with sparse silver pollen apically, dense golden-brown pollen in middle basally, and black setae. Femur II usually with posterior row of short (length less than half width of femur) white hairs on basal half, these hairs becoming black on apical half. Tarsus I(1) normal, about twice as long as tarsus I (2). Wing (Fig. 16G) hyaline, with three brown spots: one between R 4+5 and M 1 near midpoint of wing, one apically in cell bm+dm but not reaching crossvein dm-cu, and a spot on or just above M 1 beyond crossvein dm-cu. Crossvein dm-cu meeting M 1 at a nearly 45° angle.
Remarks. Harmston and Knowlton (1945) found L. querulus "in large numbers during late summer about masonry dams in the canyons near Logan and Ogden, Utah".

Liancalus similis
Redescription. Male. Body length 6.5-8.0 mm, wing length 6.0-7.5 mm. Habitus (Fig. 9). Head: Face rather narrow, nearly parallel-sided, slightly widening toward clypeus, uniformly covered with dense silver pollen. Ommatidia near vertex slightly smaller than remaining ommatidia. Vertex covered with dense silver pollen, often with some metallic blue-green color visible near middle. Vertical setae on small elevation; ocellar tubercle prominent with 2 large setae (subequal in size to vertical setae); with 2 postocellar setae which are two-thirds length ocellar setae; postocular setae approximately one-third size of vertical setae with dorsal one-third of postocular setae black (approximately 10 black setae), ventral two-thirds white (approximately 12 setae) and more slender and slightly longer than black postocular setae. Ventral postcranial hairs (beard) rather sparse, wholly white. Palpus black, covered with dense silver pollen and sparse white hairs. Antenna black, first flagellomere about as long as wide, broadly pointed apically, arista inserted near midpoint of dorsal edge.
Legs: Legs concolorous with pleura, but with less silver-gray pollen. Coxa I uniformly covered with white hairs on anterior surface (length of hairs subequal to width of coxa I); with a few black, slender setae at apex. Coxa II with a few white hairs anteriorly, a couple white setae near apex, and a black ad seta just beyond 1/2. Coxa III with a few white hairs and a black dorsal seta near 1/2. Femur I and II with some short, white hairs ventrally at base (length < half width of femur). Femur III with white hairs (length ≤ width of femur) on dorsal and posterior surface at base. Tarsus I(1) short, approximately one-quarter length of tarsus I(2) (Fig. 3G); tarsus I(2) long, flattened ventrally with dense row of red-brown av setulae full-length and slightly longer row of pv setae/setulae. Ratios of tibia:tarsomeres for leg I: 14-2-8-3-3-3; for leg II: 29-20-11-3-2-2; for leg III: 33-14-15-4-2-2.
Wing (Fig. 6B): Hyaline, with extensive brown clouding on most of apical half; cell m (beyond crossvein bm-cu) with a minute, raised, black speck near middle -the area surrounding this speck usually lacks brown clouding. Veins R 4+5 and M 1 widely separated and parallel to slightly diverging at apex of wing. Wing broadly and rather evenly rounded apically, without outstanding hairs or setae. Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow.
Abdomen: Cylindrical, elongate (Fig. 2E); T1 metallic blue-green, with dense silver pollen laterally, sparser pollen dorsally and often with diffuse narrow bronze stripe. T2-T4 with large lateral blue-green spots covered with dense silver pollen, with apical one-third to one-half bronze, narrowly bronze dorsally. T5 dark bronze with metallic green reflections and sparse silver pollen. T6 bronze with some blue-green reflections and with dense silver pollen. T1-T3 with white hair laterally, longest on T1 and T2. Sternites bronze with dense silver-gray pollen on S1 and S2, sparser pollen apically. S1 bare except for lateral small tuft of white hairs at extreme base. S2 and S3 with sparse white hairs. S4 mostly bare. Hypopygium (Fig. 12B): cerci broad basally with very short slender, cylindrical lobe (subequal in length to first flagellomere of antenna), with small white hairs.
Female. Body length 5.0-7.5 mm, wing length 5.5-7.0 mm. Similar to male except for face wider, dark blue-green covered with moderate golden-brown pollen; palpus dark brown-black with sparse golden-brown pollen and black setae. Femur II with row of short (length less than half width of femur) hairs full-length posteriorly to pv, those on basal half white, those on apical half black. Tarsus I(1) normal, distinctly longer than tarsus I(2). Wing (Fig. 16E) hyaline, with three distinct brown spots: one between R 4+5 and M 1 just beyond midpoint of wing, one near apex of cell bm+dm and just crossing crossvein dm-cu, and a spot on M 1 beyond crossvein dm-cu. Cell m without black speck near middle. Crossvein dm-cu meeting M 1 at nearly 90°.
Remarks. Aldrich (1893) states the type specimens are from "Washington (state)" and described L. similis from one male and two females, and noted that "the wings of   Diagnosis. Males and females are most similar to L. genualis, but can be distinguished by having 2 intra-alar setae, whereas L. genualis only has 1 intra-alar seta. Males are further distinguished by having tarsus I with tarsomere 2 very short (Fig. 3E), cerci long (Fig. 2B), and wing as in Fig. 5B. Description. Male. Body length 7.5-8.25 mm, wing length 6.5-7.0 mm. Head: Face nearly parallel-sided above frontoclypeal suture, slightly widening below suture; with dense silver-gray pollen along eyes that is otherwise sparse revealing violet and green-blue reflections. Frontoclypeal suture near mid-face, distinctly bulging. Eyes with minute hairs between facets; ommatidia the same size throughout. Vertex with dense silver-gray pollen along eyes that is sparser medially revealing violet, green-blue, and coppery reflections. Ocellar tubercle prominent with 2 large setae; vertical setae two-thirds size of ocellar setae, on a small elevation; 2 postocellar setae similar in size to vertical setae; postocular setae half the length of vertical setae with approximately dorsal one-half black (approximately 12 black setae), remainder white and more slender and slightly longer. Ventral postcranial hairs (beard) wholly white. Palpus black, with rather dense silver pollen and black setae that are most dense basally, with brown pollen around insertion of these basal setae. Antenna black, first flagellomere a little longer than wide, rounded apically, arista inserted just before midpoint of dorsal edge.
Wing (Fig. 5B): Hyaline, with anterior third somewhat brownish and a diffuse brown spot near 2/3 between R 4+5 and M 1 ; with a longitudinal spurious vein between R 4+5 and M 1 that is arched on apical third of wing and terminates near midpoint of a nearly circular, translucent, apical spot that is white in certain lights; this spot enclosed within a small, brown, apical cloud. Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow.
Abdomen: Cylindrical, elongate (Fig. 2B), bronze with large metallic bluegreen spots with dense silver pollen laterally at base of T1-T4 which do not meet dorsally (except occasionally on T1 which is largely blue-green). T5 metallic green dorsally with sparse silver pollen. T6 wholly metallic green with sparse silver pollen. T1-T3 and base of T4 with white hair laterally, longest on T1 and T2. Sternites bronze with silver-gray pollen. S1 bare except for lateral tuft of 3-5 white hairs at extreme base. S2 and S3 with sparse white hairs. S4 mostly bare. T5 with a few white hairs ventrally and a row of black setae along posterior margin. Hypopygium (Fig. 10B): cerci almost as long as abdomen, slender, cylindrical (though often shriveled when dried), sparsely covered with whorls of long, pale yellow setae.