Empis (Anacrostichus) spectabilis Loew, 1862

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 : 346-350

Empis (Anacrostichus) spectabilis Loew, 1862

Figs 29–35.

Empis spectabilis Loew, 1862: 196 (♀) [Cent. 2, no. 21]. Type locality: USA, Maryland .

Additional reference: Melander, 1902: 311 (♂), fig. 109.

MATERIAL EXAMINED. USA. Virginia: Falls Church , iv30 Va, C. T . Greene Collector , Empis spectabilis Lw. (2 ♂♂, OUMNH) . Maryland: Cabin John , 28.iv.1927, J.M. Aldrich Coll (1 ♂, OUMNH) . Tennessee: Sevier Co. GSMNP, Twin Cks , MT 35°41.10′N 83°29.94′W , 29.iii.–15.iv.1999, Parker, Stocks, Petersen (2 ♂♂, 1 ♀, CNC) .

DIAGNOSIS. Rather large, robust species (body about 7 mm) with densely greyish pruinose thorax and abdomen; male eyes nearly holoptic; mesoscutum with indistinct vittae, acrostichal setae absent; legs almost entirely yellow, strongly spine-like setose, hind femur thickened. Male: mid femur near base with tubercle covered with spine-like setae; tergite 6 with yellow, shiny, antero-lateral spot. Female: segments 7–8 yellowish.

DESCRIPTION. Body length about 7 mm, wing 7.4 mm. Male (Fig. 29). Head capsule regions densely, light grey pruinose, black setose; face with narrow, subtriangular, shiny spot on lower margin, clypeus narrowly shiny along upper margin, ocellar triangle subshiny around ocelli. Eyes almost touching before middle of frons, ommatidia of equal size. Frons on narrowest portion narrower than anterior ocellus, slightly broadened just below ocellar triangle, strongly broadening towards antennae beyond middle; with marginal setulae. Face broad, bare. Ocellar setae short, fine. Postocular setae fine, very short on upper part, longer laterally; occiput with numerous long setae. Antenna with scape and pedicel yellowish brown, postpedicel and stylus black; scape nearly 2.5X longer than subglobular pedicel, with rather long setulae, pedicel with short setulae; postpedicel long (nearly 4X as long as basal width), with straight margins; stylus very short, nearly as long as postpedicel basal width. Proboscis with labrum mostly yellow, brownish yellow near apex; nearly 1.5X longer than eye height; palpus short, yellow; with long, fine, black setae.

Thorax mostly black, postpronotal lobe, postalar tubercle and meron narrowly anteriorly yellowish translucent; mostly densely greyish pruinose; black setose; mesoscutum with 4 dark, indistinct, narrow vittae (dorsal view). Prosternum bare. Proepisternum with numerous long, fine setae on lower part and 3–5 similar setae on upper part. Antepronotum with numerous strong, short setae dorsally and fine, long setae laterally. Postpronotal seta present or undifferentiated; lobe covered with short to moderately long fine setae. Mesonotal setae: acrostichals absent; presutural dorsocentrals rather long, fine, arranged in 3–4 irregular rows, postsutural dorsocentrals irregularly biserial, setae of inner row somewhat inclinate, becoming longer towards scutellum, 2–3 prescutellars strongest; 1 weak presutural supra-alar (with additional shorter setae; sometimes inconspicuous or of different robustness on right and left sides); usually 4 notopleurals (sometimes 5), 2–3 postsutural supra-alars (with additional fine and shorter setae), 1 postalar, usually 6 scutellars (with some number of additional short, fine setae; sometimes 4 strong setae or different number on right and left sides); in addition, some setulae present on notopleural depression anteriorly. Laterotergite with numerous setae. Anterior and posterior spiracles pale yellow.

Legs robust; almost entirely yellow, only coxae near extreme base, tarsomeres 1–4 on apex and entire tarsomere 5 darkened. Coxae faintly pruinose, remaining podomeres subshiny. Coxae and trochanters with simple setae. Fore femur with row of long, strong anteroventral setae on about apical 2/3 to 1/2 and fine setae on remaining basal portion; row of short, strong posteroventral setae on about apical 1/2 to 1/3 and minute posteroventral setae on remaining basal portion. Fore tibia with rows of 5–6 short strong anterodorsal and posterodorsal setae; 1–2 similar posteroventral setae on middle part. Fore basitarsus slightly thickened, not broader than fore tibia on apex; with 1 short, weak anterodorsal and 1 similar posterodorsal setae on about middle; 4–5 very short, fine anteroventral setae. Mid femur (Fig. 30) near base with ventral tubercle covered spinules; bearing row of moderately long anterodorsal setae and similar setae anteriorly; numerous spine-like setae anteroventrally and row of similar posteroventral setae. Mid tibia with 5–6 strong, moderately long anterodorsal and 5–6 similar posterodorsal setae; complete rows of numerous, short, spine-like anteroventral and posteroventral setae. Mid basitarsus with spine-like anteroventral and posteroventral setae. Hind femur (Fig. 30) strongly thickened on about apical 2/3; with numerous strong setae anterodorsally and anteriorly on thickened part; numerous spine-like setae along entire anteroventral surface (somewhat denser closer to apex), similar setae on about apical half ventrally and posteroventrally. Hind tibia slightly geniculate and thickened; with numerous anterodorsal and posterodorsal, moderately long setae; covered with simple, greatly reduced setulae ventrally; 1 short seta in posteroapical comb. Hind basitarsus slender; with 2–3 fine, moderately long anterodorsal and 2–3 posterodorsal setae; spine-like anteroventral and posteroventral setae.

Wing membrane brownish infuscate; entirely covered with microtrichia; veins mostly brownish (costa between base and margin of pterostigma, Sc and R 1 yellowish), well sclerotized. Veins R 5 and M 1 slightly divergent near wing margin; radial fork acute; CuA+CuP (anal vein) complete; cell dm short, with strongly elongate apex; apical portion of M 4 nearly 3X longer than its middle portion. Pterostigma brownish. Two basal costal setae (anterior seta longer). Anal lobe well-developed; axillary incision very acute. Squama yellow, dark fringed. Halter yellow.

Abdomen brownish in ground-colour, tergites 6–7 and sternites somewhat yellowish translucent; almost entirely greyish pruinose, tergite 6 with shiny spot anterolaterally; black setose. Tergites 2–5 with scattered setulae dorsally and long setae laterally (including strong posteromarginals); tergites 6–7

Figs 29–32. Empis (Anacrostichus) spectabilis Loew, 1862: 29–31 — male: 29 — habitus, lateral view; 30 — mid and hind legs, anterior view; 31 — postabdomen, lateral view. 32 — female, habitus, lateral view. Abbreviations: cerc — cercus; epand — epandrium; hypd — hypandrium; T — tergite; S — sternite. Scale bar is 1 mm.

Рис. 29–32. Empis (Anacrostichus) spectabilis Loew, 1862: 29–31 — самец: 29 — габитус, вид сбоку; 30 — среднЯЯ и ЗаднЯЯ ноги, вид спереди; 31 — постабдомен, вид сбоку. 32 — самка, габитус, вид сбоку. Abbreviations: cerc — церк; epand — Эпандрий; hypd — гипандрий; T — тергит; S — стернит. Масштаб 1 мм.

348 Nearctic species of the empidid subgenus Anacrostichus

Figs 33–35. Empis (Anacrostichus) spectabilis Loew, 1862 , male: 33 — outline of postabdomen, lateral view; 34 — hypopygium, lateral view (setation omitted); 35 — phallus, lateral view. Abbreviations: cerc — cercus; ej apod — ejaculatory apodeme; epand — epandrium; goncx apod — gonocoxal apodeme; hypd — hypandrium; ph — phallus; ph pl — phallic plate; T — tergite; S — sternite. Scale bar is 0.1 mm.

Рис. 33–35. Empis (Anacrostichus) spectabilis Loew, 1862 , самец: 33 — строение постабдомена, вид сбоку; 34 — гипопигий, вид сбоку (Щетинки не покаЗаны); 35 — 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 0,1 мм.

with minute setulae; tergite 8 with moderately long, fine setae laterally. Sternites 1–4 and 8 with long, fine setae. Postabdomen (Figs 31, 33): 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 somewhat concave lateral margin posteriorly; slightly produced posterior lateral corner. Sternite 5 gently rounded medially, bearing cluster of several spine-like median setae and scattered setulae laterally; with two short, digitiform, bare, posterior projections. Tergite 6 slightly asymmetrical; somewhat narrower than tergite 5; with rather large, rounded antero-lateral tubercle (shiny yellow in situ) and small posteromarginal lateral projection; weaker sclerotised on about middle laterally. Sternite 6 invisible in situ, strongly reduced, represented by small, strongly sclerotised, bare, median sclerite anteriorly (rounded anteriorly and digitiform posteriorly, partly hidden by sternite 5). Tergite 7 slightly asymmetrical; narrower and 2–2.5X shorter than tergite 6; with small, anteromarginal lateral excavation. Sternite 7 asymmetrical, with scattered setulae laterally; divided by broad membranous space into two portions narrowly connected laterally; anterior portion (mostly invisible in situ) asymmetrical, strongly sclerotised, deflected downwards, including two small separated anterior sclerites and larger posterior sclerite (concave posteriorly); posterior portion represented by small, asymmetrical, weakly sclerotised, lateral sclerite. Segment 8 nearly funnel-like, with entirely separated tergite and sternite; tergite 8 rather trapezoid in lateral view, long, slightly longer than tergite 7, undivided, somewhat concave anteriorly, gently rounded posteriorly; sternite 8 nearly as long as tergite 8, with simple structure and vestiture.

Terminalia (Fig. 33–35) rather small; epandrial lamella mostly yellow, brownish yellow along upper margin; cercus largely yellow, black along lower margin on about apical half; (lateral view), becoming gradually slenderer towards apex, hypandrium brownish yellow; phallus yellow. Epandrium short apical portion very slender; with spinules before slender entirely divided (epandrial bridge absent); epandrial lamella apical portion. Ejaculatory apodeme rather large, extended far rather subrectangular (Fig. 34), upper posterior corner beyond basal curvature of phallus, with small lateral wings.

slightly produced, pointed; with rather short black setae more Female (Fig. 32). Similar to male except as follows. numerous and stronger along lower margin. Hypandrium Eyes divided by broad frons, below ocellar triangle nearly as separated from epandrium; entirely sclerotised; very broad as distance between inner margins of posterior ocelli, prolonged and deeply concave posteriorly forming two long somewhat broadening towards antennae. Body generally with subtriangular lobes; bearing numerous strong setae near base; shorter setae. Abdominal segments 7–8 brownish yellow; gonocoxal apodeme small. Subepandrial sclerite undivided. sternite 6 entirely divided. Cercus long, slender, with scattered Cerci separated with each other and from epandrium; cercus setulae.

small, narrow, rather subtriangular (lateral view), with apex REMARKS. Habitually Empis spectabilis resembles nearly pointed, posterior margin extending nearly to apex of species of the E. (Polyblepharis) albicans group occurring epandrial lamella; undivided, with smoothed inner margin; in steppe regions of the Central Europe, the European part of covered with simple dark setulae, bearing cluster of setulae on Russia and Central Asia.

inner surface. Hypoproct membraneous, bare. Phallus (Fig. 35) DISTRIBUTION. USA (Connecticut, Maryland, North mostly hidden, only slender apical portion usually extending Caroline, Tennessee, Virginia).

beyond cerci; gently arched; very thick near basal curvature

Fig. 36. Empis (Anacrostichus) verralli Collin, 1927 , male, habitus, lateral view. Scale bar is 1 mm.

Рис. 36. Empis (Anacrostichus) verralli Collin, 1927 , самец, габитус, вид сбоку. Масштаб 1 мм.

350 Nearctic species of the empidid subgenus Anacrostichus