Empis (Anacrostichus) scoparia Coquillett, 1903

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 : 342-344

Empis (Anacrostichus) scoparia Coquillett, 1903

Figs 21–24.

Empis scoparia Coquillett, 1903: 269 (♂). Type locality: USA, New Hampshire, Franconia .

MATERIAL EXAMINED. CANADA. New Brunswick: Lower Southampton , York Co. // Empis scoparia Coq. det. G.E. Shewell ’47 (1 ♂) . Alberta: [no data], C.E. Yauch (1 ♂) .

DIAGNOSIS. Mid-sized species (body about 6 mm); male eyes dichoptic, frons shiny; palpus brownish yellow; mesoscutum extensively shiny, acrostichal setae present; femora and tibiae yellow; abdomen extensively shiny; male abdominal sternite 5 with large, rounded projection bearing long, strong setae, sternite 8 strongly produced downwards.

DESCRIPTION. Body length about 6 mm, wing 6.8 mm. Male. Head with ocellar triangle, occiput, postgena and gena faintly greyish pruinose; frons and face mostly shiny, clypeus entirely shiny. Eyes dichoptic, ommatidia equally small. Frons broad, with marginal setulae. Face broad, bare. Ocellar setae fine, moderately long. Occiput covered with black, moderately long, strong setae; postgena with pale, long, hair-like setae. Antenna with scape and pedicel brownish, postpedicel and stylus black; scape nearly 2X longer than subglobular pedicel, both with short setulae; postpedicel long (nearly 4X as long as basal width), with straight margins, its base slightly broader than pedicel; stylus very short, slightly shorter than postpedicel basal width. Proboscis with labrum mostly brownish yellow, brownish near base; nearly 1.5X longer than eye height; palpus short, brownish yellow; with fine, black setae.

Thorax mostly black, only postalar tubercle yellowish translucent; mostly faintly greyish pruinose; mesoscutum extensively shiny leaving narrowly pruinose lateral and posterior margins. Prosternum bare. Proepisternum with numerous long, fine, yellow setae on lower part, bare on upper part. Antepronotum with numerous black, strong setae dorsally and 3–4 yellow, fine setae laterally. Postpronotal lobe with several moderately long, strong, black setae (1 seta slightly stronger) and a few pale setulae posteriorly. Mesonotal setae: acrostichals brownish yellow, very short, fine, scattered, 1–2-serial; presutural dorsocentrals similar to acrostichals, arranged in 2 irregular rows, postsutural dorsocentrals longer, 1 pair of prescutellars black, strong, nearly as long as scutellars; 1 short, weak presutural supra-alar; 4–5 notopleurals, 1 postsutural supra-alar, 1 postalar, 4 scutellars (apical pair slightly longer); in addition, fine brownish setulae present on notopleural depression anteriorly. Laterotergite with intermixed brownish and yellow setae. Anterior and posterior spiracles brown.

Legs with coxae and trochanters brown, femora and tibiae yellow, tarsi brown (except yellow base of basitarsus). Fore femur mostly with minute anteroventral and posteroventral setae, somewhat longer and stronger setae only near apex. Fore tibia with short, inconspicuous, dorsal setae. Mid femur with almost complete rows of equally short, spine-like setae (absent near base). Mid tibia with 2–3 short strong anterodorsal and posterodorsal setae. Hind femur rather slender, only slightly broader than mid femur; with complete rows of short spine-like anteroventral and posteroventral setae; dense spinule-like setulae over ventral face; 2 short spine-like setae near apex anteriorly. Hind tibia slender, with 4–5 short strong anterodorsal and posterodorsal setae; covered with erect setulae ventrally; no seta in posteroapical comb. Fore and hind basitarsi slender, with short setae.

Wing membrane very faintly infuscate or hyaline; entirely covered with microtrichia; veins brownish to yellowish brown, well sclerotized. Veins R 5 and M 1 slightly divergent towards wing margin; radial fork acute; CuA+CuP (anal vein) complete; cell dm short, with strongly elongate apex; apical portion of M 4 nearly 2.5X longer than its middle portion. Pterostigma brownish. Basal costal seta absent. Anal lobe well-developed; axillary incision very acute. Squama yellow, pale fringed. Halter yellow.

Abdomen black, extensively shiny. Tergite 1 entirely densely greyish pruinose, tergites 6 and 7 mostly faintly pruinose; tergites 1–3 with longer intermixed brownish and pale, fine setae laterally and minute setae dorsally; remaining tergites with minute setae (somewhat longer on tergite 8). Sternite 1 bare; sternites 2–4 and 8 with scattered pale and brownish setulae. Postabdomen (Figs 21, 22): segments 5–8 modified. Tergite 6 and segment 7 somewhat bent downward, accordingly segment 8 and terminalia shifted to ventral position relative to body axis. Tergite 5 with somewhat concave lateral margin posteriorly; small excavation on slightly produced posterior lateral corner. Sternite 5 with very large median projection bearing two narrowly separated clusters of dense, long, strong setae on apex and two small, closely set, bare posteromarginal projections. Tergite 6 slightly asymmetrical and somewhat narrower than tergite 5; with small tubercle in posterior lateral corner. Sternite 6 invisible in situ (hidden by sternite 5), strongly reduced, represented by small, weakly sclerotised sclerite, with few setulae posteriorly. Tergite 7 narrower and nearly 2X shorter than tergite 6; with small, anteromarginal lateral excavation; anterior margin concave. Sternite 7 asymmetrical, bare; divided by broad median membranous space into two portions narrowly connected laterally; anterior portion larger, deflected downwards, with small, median and two lateral, subglobular projections (lateral projections asymmetrical); posterior portion represented by two elongate oval, asymmetrical sclerites narrowly separated medially. Segment 8 funnel-like, with entirely separated tergite and sternite (lateral view). Tergite 8 long, nearly as long as tergite 7, undivided, somewhat concave anteriorly and deflected posteriorly. Sternite 8 rather subtriangular in lateral view, slightly longer than tergite 8; strongly produced downwards; with simple vestiture.

Terminalia (Figs 21–24) moderately large; epandrial lamella brown, shiny; cercus brownish yellow, subshiny; hypandrium brownish on basal part and brownish yellow on apical part; phallus yellow. Epandrium entirely narrowly divided (epandrial

Figs 21–24. Empis (Anacrostichus) scoparia Coquillett, 1903 , male: 21 — postabdomen, lateral view; 22 — outline of postabdomen, lateral view; 23 — hypopygium, lateral view (setation omitted); 19 — 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. 21–24. Empis (Anacrostichus) scoparia Coquillett, 1903 , самец: 21 — постабдомен, вид сбоку; 22 — строение постабдомена, вид сбоку; 23 — гипопигий, вид сбоку (Щетинки не покаЗаны); 19 — 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.

bridge absent); epandrial lamella rather subrectangular (Fig. 23); portion (lateral view). Ejaculatory apodeme moderately large, with scattered setulae. Hypandrium separated from epandrium; extended far beyond basal curvature of phallus, with small entirely sclerotised; subtriangular (ventral view), short, lateral wings.

with small notch on apex; bare; gonocoxal apodeme small. Female. Unknown.

Subepandrial sclerite undivided. Cerci separated with each other REMARKS. Empis scoparia is a unique species of and epandrium; cercus small, narrow, rather subrectangular Anacrostichus by the structure of the abdominal sternite 8 of (lateral view), produced downwards posteriorly, posterior the male.

margin extending nearly to apex of epandrial lamella; undivided, DISTRIBUTION. Canada (Alberta, New Brunswick), with smoothed inner margin; covered with simple dark USA (New Hampshire).

setulae, bearing scattered setulae on inner surface. Hypoproct membraneous, bare. Phallus (Fig. 24) hidden; gently arched;

thickened on about basal 1/2, uniformly slender on remaining

344 Nearctic species of the empidid subgenus Anacrostichus