Rhamphomyia hirtula Zetterstedt

Rhamphomyia hirtula Zetterstedt

(Figs 53, 54)

Rhamphomyia hirtula Zetterstedt, 1842: 421. Type-locality: Greenland.

Other references: Melander, 1928: 194 (catalogue); Collin, 1931: 67 (faunal survey); Henriksen, 1939: 80 (Greenland list); Nielsen et al., 1954: 51 (Iceland); Messersmith, 1982: 37 (Iceland records); Barták & Danielson, 2007: 111 (type data); Barták, 2015: 576 (Greenland fauna).

Rhamphomyia (Pararhamphomyia) hirtula Zetterstedt: Frey, 1955b: 482 (revision); Chvála & Wagner, 1989: 301 (catalogue); Yang et al., 2007: 171 (catalogue); Shamshev, 2016: 64 (checklist).

Rhamphomyia (Rhamphomyia) hirtula Zetterstedt: Collin, 1961: 401 (British empidids).

Type material. Not examined (see type details in Barták & Danielson (2007: 111)).

Additional material examined. CANADA. Yukon: km 465 Dempster Hwy, 5–7.vii. 1980, 800 m, D.M. Wood & J. D. Lafontaine (1 ♂, CNC); Ogilvie Mts, Mt. Klotz, on snowfield, 65°24′N 140°06′W, 6–8.vii.1985, K. Mikkola (1 ♂, CNC); Ogilvie Mts, site #2 (helicopter), 14.vii.1985, S.A. Marshall (2 ♂, UGIC); Richardson Mts, 66°44′N 140°06′W, 3200 ft, with prey, 8.vii.1982, D.M. Wood (1 ♂, 1 ♀, CNC). GREENLAND. Tassiusak [= Tasiusaq], 24.vii.1889, Lundbeck (1 ♂, USNM); Grönlandia, Lundb. det. (1 ♂, 1 ♀, MZH). ICELAND. Myvata, sweeping west side of Vindbelgjarfjall, 1.vii.1981, 1355/1/3 –500, J.A. Downes (2 ♂, 2 ♀, CNC); Myvata, Rd. to Skutustadir, 1357/2/15, 3.vii.1981, J.A. Downes (1 ♂, CNC); Asheidi, Kelduhverfi Nord-Pingeyiarsysia, 28.vi.1981, 1352/3/1– 2, ex. with Sim. vittatum prey, O.K Nielsen & J.O. Hilmarsson (1 ♂, CNC).

Diagnosis. This black hairy species is distinguished from other species of the Rhamphomyia hirtula group by the bifurcate male cerci with hook-like dorso-basal projection, phallus filamentous apically with distinct medial loop, apex of epandrium with dorsoapical cluster of fine erect setae and ventroapical cluster of long, oblique setae. Female mid and hindlegs are without pennate setae.

Redescription. Wing length 5.5–6 mm. Male. Head dark in ground-colour, with greyish pruinescence on face, frons, and occiput; with dark setation. Holoptic, eye with ommatidia larger on upper half, smaller on lower half. Frons represented by very small triangular space below ocellar tubercle and larger subtriangular space above antennae, bare; face only slightly divergent towards mouthparts; oral margin dark brown and shiny. Ocellar triangle dark, subshiny, with 3 pairs of subequal setae; 3 pairs of postocellar setae, shorter than posterior ocellar setae. Occiput bearing row of long postocular setae on upper part only; other setae shorter and stouter; postgena setae finer than occipital setae. Antenna dark; scape 2X longer than pedicel; pedicel bulbous; postpedicel more than 2.5X longer than basal width; stylus longer than basal width of postpedicel. Palpus dark, with many long, fine, dark setulae. Clypeus pruinescent; labrum lustrous and reddish brown, apex black, longer than head height; labellum lighter brown than labrum, with dark, hair-like setae.

Thorax dark, largely dark grey pruinescent, with dark setation. Scutum with pair of faint, light grey vittae between acr and dc rows. Proepisternum with many short, hair-like setae; upper proepisternum in front of spiracle with many hair-like setae; prosternum bare. Antepronotum with row of short, stout setae. Postpronotal lobe with many setae of various lengths. Scutum with biserial, dense, fine acr; dc multi-serial, similar to acr, except slightly longer and increasing in length posteriorly; presut spal region with numerous long setae; 3–4 stout npl with numerous shorter setae anteriorly; numerous find prealar setae; 2–3 psut spal; 1 pal and 1 long seta; 6–10 pairs of sctl. Anterior and posterior spiracles pale brown.

Legs mostly reddish brown to brown with faint pruinosity and dark setation. Mid and hind coxae with many lateral hair-like, long setae; fore coxa bearing similar setae anteriorly. Femora with white ventral pile; fore femur with rows of anteroventral and posteroventral setae, longer than femur width; posterior face with similar long setae. Mid femur with 1 anteroventral and 1 posteroventral row of setae, posteroventrals longer; basal half with several anterior and dorsal setae longer than femur width. Hind femur with 1 anteroventral and 1 posteroventral row of setae, longer than width of femur (Fig. 53A); basal half with long anterior and posterior setae, longer than width of femur. Fore tibia with short, fine dense setae on posterior, anterior and ventral faces; numerous stout anterodorsal and posterodorsal setae and long thin posterior setae, longer than tibial width. Mid tibia with many rows of slender posterior setae and stout anterodorsal and posterodorsal setae longer than tibial width; numerous rows of anteroventral and posteroventral setae, becoming spine-like apically. Hind tibia (Fig. 53A) with short, fine setae posteroventrally and posteriorly; numerous rows of setae dorsally, anteriorly and anteroventrally, longer than tibial width; with 1 long seta in posteroapical comb. Hind (Fig. 53A) and mid tarsomeres 1–4 with long setae dorsally, 2X their respective widths; tarsomere 1 with stout anteroventral and posteroventral setae subequal to their respective widths; fore tarsomere 1–5 with short, fine soft setae ventrally.

Wing lightly infuscate with yellowish veins; all veins complete (except Sc), well sclerotized. Pterostigma distinct, dark yellow; basal costal seta present. Anal lobe well-developed; axillary excision forming acute angle. Halter dusky yellow to brown.

Abdomen similar colour to thorax; sternite and tergite margins pale; setae black, decreasing in length and thickness posteriorly. Sternite 8 with posterior margin bearing many dark, stout setae, mostly longer than length of sternite; ventral setae sinuous. Tergite 8 half length of sternite 8, slightly upturned posterior; posterior margin with short, dark setae; not prolonged dorsally.

Terminalia (Fig. 53B) dark brown. Epandrium ovoid-shaped, with long black setae, more dense on apical half; apex rounded with ventroapical margin with dense cluster of setae, all arched obliquely compared to other epandrial setae; dorsoapical margin with row of short, fine, dark, erect setae. Cercus subequal in width to epandrium; shorter than epandrium; cercus bifurcate, with upper margin bearing hook-like projection; tip with inner reversed flap-like setose pointed process, apical setae extended beyond margin; proximal to hook-like projection with cluster of dark, fine, erect setae. Hypandrium narrow, cylindrical, membranous anteriorly, encircling base of phallus. Base of phallus swollen, tapered to filamentous apical portion; curvature forming one lower, smaller loop, and one upper, larger loop; arched between cerci. Ejaculatory apodeme smaller than cercus, vertical wing with dorsal margin somewhat flattened, subequal in size with lateral wings.

Female. Similar to male except face broad with dense row of setulae along inner eye margin; without modified leg chaetotaxy; mid and hindlegs without pennate setae; abdominal setae shorter, less dense.

Distribution. This species is recorded from Scotland, Iceland, Greenland and several localities in the Yukon Territory (Canada) (Fig. 54). It is also known Siberia and the Russian Far East (Chukotka) (Shamshev 2016).

Remarks. The identification of this species is based on the illustrations of the male terminalia in Collin (1961, fig. 139) and Frey (1955b, fig. 370). In addition, this is one of two species of Rhamphomyia that are recorded from Iceland (Nielsen et al. 1954). Collin (1961) compared specimens from Scotland with specimens from Zetterstedt’s collection.

Rhamphomyia hirtula is very similar to R. kaninensis Frey (see Frey 1955b, p. 483), but the latter is smaller, more slender and the abdomen has greyish pruinescence, whereas the abdomen in R. hirtula is blackish brown. The hindlegs and shape of the phallus are similar in these two species, but R. hirtula is larger and more robust.