Empis (Polyblepharis) bylyrensis Shamshev

Empis (Polyblepharis) bylyrensis Shamshev , sp.n.

Figs 1–5.

TYPE MATERIAL. Holotype, male, labelled [in Cyrillic, Russian]: Bylyra [49°41′N 111°43′E, RUSSIA], Chit. obl. [=Chitinskaya oblast, now Zabaykalskiy Territory] / step. skl. [=stepnoy sklon, steppe slope] i kolki [and small forest] / V. Richter 20 vi 975 ( ZISP, INS _DIP_0000631; dissected). GoogleMaps

Paratypes. RUSSIA, Buryatia: Khamney, right shore of Dzhida River , 28.vi.1971, V . Richter (2 ♀♀, ZISP). Zabaykalskiy Terr.: Kyra , forest-steppe, 17.vi.1975, V . Richter (1 ♀, ZISP) .

DIAGNOSIS. Mid-sized species (body about 5.5 mm); all femora bearing rows of anteroventral and posteroventral spines, all tibiae with row of anteroventral spinules; mesoscutum with 4 vittae. Male: eyes holoptic, almost touching on middle part of frons. Female: eyes dichoptic, separated by broad frons.

DESCRIPTION. Body nearly 5.5 mm, wing 4.8–5 mm. Male. Head capsule regions mostly densely greyish pruinose; face on lower margin and entire clypeus shiny; head setation mostly black. Eyes almost touching on middle part of frons, upper ommatidia enlarged. Frons represented by small subtriangular spaces below ocellar triangle and above antennae; bare. Face broad, bare. Two short, fine ocellar setae. Occiput with numerous moderately long setae laterally; postocular setae very short (upper setae somewhat stronger); postgena with pale hair-like setae. Antenna with scape and pedicel brown, postpedicel and stylus black; scape slightly longer than subglobular pedicel, both with very short setulae; postpedicel nearly 2X as long as basal width, with gently concave subapical part of lower margin; stylus moderately long, slightly longer than postpedicel basal width. Proboscis with labrum brownish yellow, nearly 1.5X longer than eye height; palpus short, pale yellow; with scattered, dark and pale setulae.

Thorax black in ground-colour, densely greyish pruinose; mostly black setose; mesoscutum with 4 brown distinct vittae. Antepronotum with 4–5 black, strong setae dorsally and pale, hair-like setae laterally. Postpronotal lobe with 1 long and several short setae. Proepisternum with 5–6 black, strong and more numerous pale, hair-like setae on lower part. Prosternum bare. Mesonotal chaetotaxy reduced: acrostichal setae present in presutural part only, arranged in 2 close irregular rows, scattered, very short; dorsocentrals uniserial, very short (including prescutellars); 1 short presutural intra-alar, 1 similar presutural supra-alar, 3 long, strong notopleurals (sometimes 1 or 2 on one side), no postsutural supra-alar seta(e), 1 long and 1 minute postalars, 4 short scutellars (apical setae longer and stronger); notopleuron with scattered black and pale setulae anteriorly. Laterotergite with 3–4 strong, black and more numerous, hair-like, pale setae. Anterior and posterior spiracles yellow.

Legs with coxae densely greyish pruinose, remaining podomeres subshiny; mostly black setose. Leg colour: mostly yellow to dusky yellow; coxae, trochanters at apex, most part of fore femur (except extreme base and about apical third) and tarsomeres brownish (tarsomere 1 and basal part of tarsomere 2 sometimes paler). Fore coxa with scattered, strong, black setae and pale setulae anteriorly. All femora without whitish pilosity ventrally. All femora bearing rows of anteroventral and posteroventral spines: fore femur in about apical 1/2; mid femur in about apical 3/4; hind femur in about apical 2/3. In addition, all femora almost bare in lower half anteriorly; hind femur bearing 1 short anterior seta close to apex. Hind femur rather slender, only slightly broader than fore and mid femora. All tibiae lacking outstanding setae, only some anterodorsal and posterodorsal setulae slightly longer; fore tibia bearing row of anteroventral spinule-lake setae in about apical 1/2; mid and hind tibiae with almost complete row of similar anteroventral spinules (except close to base). Hind tibia rather slender; no seta in posteroapical comb. Hind basitarsus slightly thickened basally, becoming gently narrow towards apex (not broader than hind tibia at apex); remaining tarsomeres of all legs slender; fore and hind basitarsi with short, spinulae-like setae ventrally.

Wing membrane hyaline; entirely covered with microtrichia; veins mostly brownish (brownish yellow near extreme base), well-sclerotized. Veins R 5 and M 1 slightly divergent towards wing margin; radial fork acute; R 5 meeting costa before wing apex; CuA+CuP complete. Cell dm moderately large, with moderately elongate apex; apical portion of M 4 nearly 2X longer than its middle portion. Pterostigma brownish yellow. Basal costal seta absent. Anal lobe well-developed; axillary incision very acute. Squama yellow, pale fringed. Halter with yellow stalk and brownish knob.

Abdomen entirely brown in ground colour; tergites extensively shiny dorsally, narrowly densely greyish pruinose laterally; sternites densely greyish pruinose. Abdominal tergites covered with scattered minute setulae dorsally, tergites 1–3 bearing long, fine, pale setae laterally, with additional fine, brownish to black setae (including posteromarginals; also present on remaining tergites); sternites with scattered pale setulae. Pregenital segments: segments 6 and 7 unmodified; segment 8 with separated tergite and sternite; tergite 8 represented by two sclerites separated mid-dorsally, with several short setae posteriorly; sternite 8 somewhat enlarged, without prominent projections.

Hypopygium ( Figs 1–4) moderately large; epandrium and cerci black; epandrial lamella with short, black, rather sparse setae in apical part; cercus covered with dark setulae. Epandrium entirely broadly divided (epandrial bridge absent); epandrial lamella ( Fig. 1) rather subrectangular (lateral view), slightly narrower at apex. Hypandrium ( Fig. 2) separated from epandrium; subtriangular in ventral view, with pointed apex, bare; gonocoxal apodeme small. Cerci ( Figs 1, 3) separated with each other and from epandrium; cercus elongate ovate (lateral view), with apex extending to level of epandrial lamella apex, without lobe-like, dorsolateral projection at basal part (dorsal view), with smoothed inner margin. Phallus ( Fig. 4) almost entirely hidden; zigzag bent, not constricted beyond middle; almost uniformly thickened (ventral and dorsal tubercles present beyond middle) and gently arcuate between basal curvature and apical bend portion; apical bend portion semicircular (its tip pointing to rear), moderately long, mostly slender (except slightly thickened extreme base). Ejaculatory apodeme small, situated far beyond basal curvature of phallus, with lateral wings; sperm sac enlarged.

Female ( Fig. 5). Similar to male except as follows. Frons broad, with marginal setulae. Occiput and proepisternum with slightly shorter setae. Hind femur with row of short (slightly shorter than posteroventral spines), pennate setae just behind row of posteroventral spines in about apical half; hind tibia with fringe of short, slightly flattened posteroventral setae in about apical half. Abdomen covered with scattered, pale setulae (tergites 1–2 with longer setae laterally); mostly densely greyish pruinose; tergites 2–5 extensively shiny dorsally and pruinose laterally; in addition, tergite 2 pruinose narrowly anteriorly and tergite 5 broader posteriorly; tergite 6 mostly pruinose, narrowly shiny anteriorly (shiny space hidden by tergite 5); tergite 7 and segment 8 mostly shiny; cercus long, slender, covered with dark minute setulae.

DIFFERENTIAL DIAGNOSIS. The new species differs from all species assigned to Polyblepharis by an armature of tibiae and femora of both sexes. In E. bylyrensis sp.n. all femora bear rows of anteroventral and posteroventral spines as well as all tibiae possess a row of anteroventral spinules. In addition, the abdominal sternite 8 of the male of the new species lacks prominent projections (usually present in species of Polyblepharis ). The shape of the phallus may suggest close relationships with E. subtransbaicalica sp.n. described herein. In addition to the characters noted above, E. bylyrensis sp.n. differs from E. subtransbaicalica sp.n. by brown knob of the halter and by very short mesonotal setae.

ETYMOLOGY. The epithet refers to the type locality of the new species, Bylyra.

DISTRIBUTION. Russia (Buryatia, Zabaykalskiy Territory).