Empis (Anacrostichus) virgata Coquillett, 1895

Shamshev, I. V., 2023, Review of the Nearctic species of the subgenus Anacrostichus Bezzi, 1909 (Diptera: Empididae), Russian Entomological Journal 32 (3), pp. 330-355 : 350-354

Empis (Anacrostichus) virgata Coquillett, 1895

Figs 37–43.

Empis virgata Coquillett, 1895: 408 (♂). Type locality: USA, Washington .

Additional reference: Malloch, 1923: 184 (♀).

MATERIAL EXAMINED. CANADA. British Columbia: Metatype E. virgata Coq., Compared by C.H. Curran // Agassiz, 27.iv.1922, R . Glendenning (1 ♂); Lakelse, near Terrace, B.C., 300, 14.vi.1960, W.W. Moss (1 ♂); Tyee, 27 mi. E. Pr. Rupert, on flowers of goat’s beard, 24.vi.1960, J.G. Chillcott (1 ♀); Burnaby, 20.iv.2005, A. T . Beckenbach // Empis virgata Coq. det. B.J. Sinclair 2005 (1 ♂, 2 ♀♀) . USA, Alaska: Yakutat, June 21 ’99, Harriman Expedition ’99, T . Kincaid, Collector // Empis virgata Coq. (1 ♂, OUMNH); Sitka, June 16 ’99, Harriman Expedition ’99, T . Kincaid, Collector (1 ♀, OUMNH); same locality, Holmberg (1 ♂, MZH) . Washington: Olympia , 4.i.95 // Empis virgata Coq. (1 ♀, OUMNH) .

DIAGNOSIS. Large blackish species (body 6–8 mm); male eyes nearly holoptic;

mesoscutum greyish pruinose, with 3 brownish subshiny vittae along rows of acrostichal and dorsocentral setae; legs entirely dark brown. Male: abdominal sternite 5 with large rounded projection covered dense, short, strong setae.

DESCRIPTION. Body and wing length 6–8 mm. Male (Fig. 37). Head capsule regions mostly densely, greyish pruinose, black setose; face with subtriangular shiny spot on lower part, clypeus entirely shiny. Eyes touching on frons, upper ommatidia enlarged. Frons represented by very small subtriangular space just below ocellar triangle and larger space above antennae; with marginal setulae. Face broad, bare. Ocellar setae undifferentiated; several equally long, fine setae present. Occiput covered with long, fine, dense setae (including postoculars). Antenna black; scape nearly 3X longer than subglobular pedicel, both with long setulae; postpedicel long (nearly 4X as long as basal width); stylus very short, nearly as long as postpedicel basal width. Proboscis with labrum brownish, darker near base; nearly 1.5X longer than eye height; palpus short, brownish; with long, fine, black setae.

Thorax mostly black, only postalar tubercle somewhat yellowish translucent; mostly densely greyish pruinose; black setose; mesoscutum with 3 brownish, subshiny vittae along rows of acrostichal and dorsocentral setae (dorsal view). Prosternum bare. Proepisternum with numerous long, fine setae on lower part, bare on upper part. Antepronotum with strong, short setae dorsally and fine, long setae laterally. Postpronotal seta undifferentiated; lobe covered with long hair-like setae. Mesonotal setae: acrostichals arranged in 3–5 irregular rows (variable character), long, hair-like, dense, usually absent on prescutellar depression (rarely present); presutural dorsocentrals multiserial and not separated from similar presutural supra-alars anteriorly, long, hair-like, postsutural dorsocentrals sparser and longer, intermixed fine and somewhat stronger setae, usually 2 strongest prescutellars; presutural supra-alar undifferentiated, numerous hair-like setae present somewhat stronger in front of suture; 4–6 notopleurals (variable), 2–3 postsutural supra-alars (with additional fine and shorter setae), 1 postalar, 6–8 scutellars (usually with some number of additional shorter, fine setae); in addition, numerous setulae present on notopleural depression anteriorly. Laterotergite with numerous setae. Anterior and posterior spiracles brownish.

Legs long, slender, entirely dark brown, black setose. Coxae greyish pruinose, remaining podomeres subshiny. Coxae and trochanters with simple setae. All femora whitish pubescent ventrally. Fore femur with row of short, mostly fine, anteroventral setae (somewhat stronger near apex); long, dense, hair-like setae posteroventrally. Fore tibia with rows of 5–6 short anterodorsal and posterodorsal setae. Fore basitarsus slightly thickened or sometimes nearly slender; with spinule-like anteroventral setulae. Mid femur with stronger setulae anteriorly; anteroventral complete row of numerous, short, strong setae (somewhat longer and finer near base); posteroventralrowofsimilarbutsomewhatlongersetae;spinule-like ventral setulae on about basal half. Mid tibia with rows of 5–6 short anterodorsal and longer posterodorsal setae; anteroventral and posteroventral spine-like setae (except about basal 1/3). Mid basitarsus with anteroventral and posteroventral spine-like setae. Hind femur slender, only slightly broader than mid femur; with short, spine-like, rather sparse anteroventral setae; simple setulae ventrally and posteroventrally. Hind tibia simple; slightly gently thickened towards apex; with rows of very short anterodorsal and longer posterodorsal setae; simple setulae ventrally; very short seta in posteroapical comb. Hind basitarsus slender; with 2–3 very short anterodorsal setae, spine-like anteroventral and posteroventral setae.

Wing membrane brownish infuscate; entirely covered with microtrichia; veins brownish, well sclerotized. Veins R 5 and M 1 almost parallel near wing margin; radial fork acute; CuA+CuP (anal vein) complete; cell dm short, with strongly elongate apex; apical portion of M 4 nearly 2X longer than its middle portion. Pterostigma brownish. Basal costal seta present, short. Anal lobe well-developed; axillary incision very acute. Squama yellow, dark fringed. Halter yellow.

Abdomen dark brown, black setose. Tergites 2–5 subshiny (except tergite 2 narrowly greyish pruinose along anterior margin), tergites 1, 6–8 faintly greyish pruinose; tergites 2–4 Figs 37, 38. Empis (Anacrostichus) virgata Coquillett, 1895 , habitus, lateral view: 37 — male; 38 — female. Scale bar is 1 mm. Рис. 37, 38. Empis (Anacrostichus) virgata Coquillett, 1895 , габитус, вид сбоку: 37 — самец; 38 — самка. Масштаб 1 мм.

352 Nearctic species of the empidid subgenus Anacrostichus with short setae dorsally and long, dense setae laterally (including some stronger posteromarginals), tergites 5–8 with scattered setulae. Sternites faintly greyish pruinose (projection of sternite 5 subshiny); sternites 1–4 with sparse, long, fine setae. Postabdomen (Figs 39, 40):segments 5–8 modified.Tergite 6 and segment 7 somewhat bent downwards, accordingly segment 8 and terminalia shifted to ventral position relative to body axis. Tergite 5 with slightly produced posterior lateral corner.Sternite 5 with very large, median, subrectangular projection covered with dense, spine-like setae on apex. Tergite 6 slightly asymmetrical; somewhat narrower than tergite 5; somewhat concave laterally closer to anterior margin, with slightly produced posterior lateral corner. Sternite 6 invisible in situ (hidden by sternite 5), strongly reduced, represented by small, weakly sclerotised, bare sclerite. Tergite 7 slightly asymmetrical; narrower and 2–2.5X shorter than tergite 6, with small, anteromarginal lateral excavation. Sternite 7 deeply concave laterally forming two narrowly connected portions; anterior portion stronger sclerotised, represented by two very large, L-shaped, fused, asymmetrical lobes (in situ appressed to sternite 6), with short setae near upper

Figs 39–43. Empis (Anacrostichus) virgata Coquillett, 1895 , male: 39 — postabdomen, lateral view; 40 — outline of postabdomen, lateral view; 41 — hypopygium, lateral view (setation omitted); 42 — hypandrium, ventral view; 43 — phallus, lateral view. Abbreviations: cerc — cercus; ej apod — ejaculatory apodeme; epand — epandrium; goncx apod — gonocoxal apodeme; hypd — hypandrium; ph — phallus; ph pl — phallic plate. Scale bar is 1 mm.

Рис. 39–43. Empis (Anacrostichus) virgata Coquillett, 1895 , самец: 39 — постабдомен, вид сбоку; 40 — строение постабдомена, вид сбоку; 41 — гипопигий, вид сбоку (Щетинки не покаЗаны); 42 — гипандрий, вид сниЗу; 43 — фаллус, вид сбоку. СокраЩениЯ: cerc — церк; ej apod — ЭЯкулЯторнаЯ аподема; epand — Эпандрий; goncx apod — гонококсальнаЯ аподема; hypd — гипандрий; ph — фаллус; ph pl — пластина фаллуса; T — тергит; S — стернит. Масштаб 1 мм. margin; posterior portion elongate, subtriangular (ventral view), Mesoscutum with very short acrostichal and dorsocentral asymmetrical, mostly membranous, narrowly sclerotised along setae. Femora not pubescent ventrally. Fore femur with simple lateral margins. Segment 8 funnel-like, with entirely separated setulae, bearing minute anteroventral and posteroventral setae. tergite and sternite of subequal width (lateral view); tergite Fore basitarsus slender. Mid femur with simple setulae, bearing 8 long, longer than tergite 7, undivided, somewhat concave very short anteroventral and posteroventral setae. Mid tibia anteriorly and deflected posteriorly; sternite 8 subtriangular in with spine-like setae ventrally; 2–3 very short posteroventral lateral view, slightly longer than tergite 8, with simple structure setae (sometimes inconspicuous). Hind femur with very short, and vestiture. sparse anteroventral setae, otherwise covered with simple

Terminalia (Fig. 41–43) moderately large, black setose; setulae. Abdomen with much shorter setation; tergites 7 and 8 epandrium brown, cerci brownish to yellowish brown. greyish pruinose. Cercus long, slender, with scattered setulae. Epandrium entirely narrowly divided (epandrial bridge absent); REMARKS. Empis virgata is a unique species of epandrial lamella rather subtriangular (Fig. 41); with long black Anacrostichus by the curious structure of the abdominal setae along lower margin. Hypandrium (Fig. 42) separated from sternite 7 of the male. epandrium; entirely sclerotised, subtriangular (ventral view), DISTRIBUTION. Canada (British Columbia), USA cleft apically, bare; gonocoxal apodeme small. Subepandrial (Alaska, Washington). sclerite undivided. Cerci separated with each other (appressed anteriorly), appressed to dorsal margin of epandrium; cercus Empis (Anacrostichus) sp. 1 small, narrow, convex dorsally, as in Fig. 41, posterior margin Figs 44–46. extending nearly to apex of epandrial lamella; undivided, with smoothed inner margin; covered with simple dark MATERIAL EXAMINED. USA. Alabama: Baldwin Co., setulae, bearing scattered setulae on inner surface. Hypoproct North Delta (site 25), Malaise, 31.13N 87.85W, 23.v.2004, E. membraneous, bare. Phallus (Fig. 43) hidden; gently arched; Benton (1 ♂). thickened on about basal 1/3, uniformly slender on remaining DIAGNOSIS. Male (Figs 44, 45). Mid-sized (body about portion (lateral view). Ejaculatory apodeme moderately large, 4.5 mm; wing 5.0 mm) species with yellow body and legs. extended far beyond basal curvature of phallus, with small Very similar to Empis pallida except as follows. Frons below lateral wings. ocellar triangle nearly as broad as anterior ocellus. Antenna

Female (Fig. 38). Similar to male except as follows. with scape and pedicel brownish yellow, postpedicel entirely Body and legs generally with much shorter setae. Dichoptic, brown. Thorax with prescutellar depression and anterior ommatidia equally small. Frons very broad, broader than face of scutellum dark, greyish pruinose. Pronotum with distance between outer margins of ocelli; mostly shiny. 5 strong black setae on each side. Fore femur with fine setae

Figs 44–46. Empis (Anacrostichus) sp. 1, male: 44 — habitus, lateral view; 45 — same, dorsolateral view; 46 — postabdomen. Abbreviations: cerc — cercus; epand — epandrium; ph — phallus; T — tergite; S — sternite.

Рис. 44–46. Empis (Anacrostichus) sp. 1, самец: 44 — габитус, вид сбоку; 45 — тоЖе, вид сверху- сбоку; 46 — постабдомен. СокраЩениЯ: cerc — церк; epand — Эпандрий; ph — фаллус; T — тергит; S — стернит.

354 Nearctic species of the empidid subgenus Anacrostichus near apex, some anteroventrals slightly stronger. Abdomen with dark setae; tergites 2–5 rather yellowish brown, tergites 2–4 broadly pale posteriorly. Postabdomen (Fig. 46) as in E. pallida . Terminalia very similar to E. pallida but epandrial lamella somewhat narrower.

REMARKS. This single, somewhat damaged, specimen could be associated only with E. pallida . However, there are some differences suggesting that another, yet undescribed, species may be present. Additional material should be examined to make a final conclusion. It should be noted that all known records of E. pallida refer to the areas with rather temperate climate (Ontario of Canada, the New England region of the USA). The unnamed specimen was collected from the territory with subtropical maritime climate (near the Gulf of Mexico).