Hercostomus pailongensis, Tang, Chufei, Zhang, Lili & Yang, Ding, 2014

Tang, Chufei, Zhang, Lili & Yang, Ding, 2014, New species of Hercostomus baishanzuensis group from Tibet (Diptera: Dolichopodidae, Dolichopodinae), Zootaxa 3881 (6), pp. 549-562 : 561

Hercostomus pailongensis sp. nov.

( Figs 9, 10, 22, 23 )

Diagnosis. First flagellomere nearly triangular, blunt at tip. Basal segment of arista 0.4 times as long as apical portion of arista ( Fig. 22 ). Postgonite large, thickened at middle, hooked at tip. Cercus nearly square, distinctly longer than wide, with long black bristles. Phallus short, hidden in hypandrium ( Fig. 23 ).

Description. Male ( Fig. 9). Body length 2.4 mm, wing length 2.8 mm. Head dark metallic green, with pale gray pollinosity; face gradually narrowed downward. Hairs and bristles on head black, postocular bristles black, posteroventral hairs pale. Antenna ( Fig. 22 ) black, first flagellomere somewhat brownish; first flagellomere nearly triangular, blunt at tip, 1.4 times longer than wide, with short yellowish pubescence; arista subapical, slightly longer than head width, basal segment black, apical portion of arista gradually lighter toward tip, almost bare, basal segment 0.4 times as long as apical portion of arista. Proboscis dark yellow with brown hairs and 1 weak black bristle; palpus dark brown, with 3 black bristles on dorsum and 1 bristle at tip. Thorax dark metallic green, with pale gray pollinosity. Hairs and bristles on thorax black; 5 dc, 6 pairs of sparse acr. Scutellum with 2 pairs of sc. Legs mainly yellow, but coxae brownish, femora dark yellow on dorsum, tibiae brownish at tip, tarsi brown to black toward tip. Hairs and bristles on legs mostly black, hairs on coxae brownish. Fore coxa with 3 d near apex. Mid and hind coxae each with 1 outer bristle. Fore femur with 1 v, 1 pv; with 3 apical bristles. Mid femur with 1 preapical av. Fore tibia apically with 3 bristles. Mid tibia with 2 ad, 1 av; apically with 3 bristles. Hind tibia with 9 ad in 1 row, 2 av; apically with 1 bristle. Fore tarsomere 1 with 1 short ad. Mid tarsomere 1 apically with 1 short bristle. Hind tarsomere 1 with 2 pd; apically with 2 short bristles. Relative length of tibia and 5 tarsomeres of legs LI: 2.5: 1.2: 0.5: 0.4: 0.3: 0.4; LII: 3.2: 1.4: 0.9: 0.8: 0.6: 0.5; LIII: 3.8: 1.2:?:?:?:?; LIII broken. Wing nearly hyaline, tinged brown; veins brown, R4+5 and M1+2 slightly convergent apically. CuAx ratio 0.6. Squama dark brown with 8 black hairs. Halter pale yellow. Abdomen dark metallic green, with thick pale gray pollinosity. Hairs on abdomen pale, bristles on abdomen black. Male genitalia ( Fig. 23 ): Epandrium distinctly longer than wide; inner epandrial lobe protuberant at middle, with 1 long bristle near tip, outer epandrial lobe thin, long, slightly protuberant near tip, with 1 long bristle at middle, 2 bristles at tip. Inner surstylus bifurcated near base, ventral arm long, with 1 long bristle at base, dorsal surstylus long, thin. Postgonite big, thickened at middle, hooked at tip. Cercus nearly square, distinctly longer than wide, with several digitations, and with black hairs and long bristles. Phallus short, hidden in hypandrium. Female ( Fig. 10). Body length 2.6 mm, wing length 2.7 mm. Almost same as male, but first flagellomere 1.2 times longer than wide. Apical portion of arista of arista somehow brownish.

Type material. HOLOTYPE, ♂ labeled: China: Tibet, Bomi, Pailong (N30°01'08.4" E95°06'74.4"), 2560 m, 2013. IX.8, Gang Yao ( CAU). PARATYPES: 4 ♂ 1 ♀, same data as holotype.

Distribution. Oriental: China (Tibet).

Remarks. The new species is similar to H. basalis (Yang) from Xinjiang of China, but may be separated from the latter by the big, apically-hooked postgonite and long bristles of male cercus. In H. basalis , the postgonite and the bristles of male cercus are relatively short ( Yang 1996b).

Etymology. The species is named after the type locality Pailong.

Figures

FIGURES 22 – 23. Hercostomus pailongensis sp. nov., male. 22. Antenna, scale bar = 0.2 mm; 23. Genitalia, lateral view, scale bar = 0.3 mm. Abbreviations: epn = epandrium, hyp = hypandrium, ph = phallus, sur = surstylus, lat = epandrial lobe, cer = cercus.