Hercostomus flavus, 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 : 556-558

Hercostomus flavus sp. nov.

( Figs 4, 16, 17 )

Diagnosis. First flagellomere pointed at tip. Basal segment of arista 0.1 times as long as apical portion of arista ( Fig. 16 ). Cercus mainly brown, but yellowish at base, nearly triangular, with several long digitations ( Fig. 17 ).

Description. Male ( Fig. 4). Body length 3.4 mm, wing length 3.5 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 black ( Fig. 16 ), first flagellomere slightly brownish at tip; first flagellomere pointed at tip, 1.3 times longer than wide, with brown pubescence; arista subapical, longer than width of head, black, almost bare, basal segment 0.1 times as long as apical portion of arista. Proboscis dark yellow with brown hairs; palpus dark brown, with pale hairs and 3 black dorsal bristles at tip. Thorax dark metallic green, with pale gray pollinosity. Hairs and bristles on thorax black; 6 long, strong dc, 8–9 pairs of acr. Scutellum with 2 pairs of sc, inner pair long strong, outer pair very short. Legs mainly black, fore leg mainly blackish, but trochanters and mid portions of tibiae yellow; fore and mid tarsi brown to black toward tip. Hairs and bristles on legs black. Fore coxa with 2 d at apical half; with 2 apical bristles. Mid coxa with 1 d at middle. Hind coxa with 1 outer bristle. Fore tibia with 1 weak ad, 1 pd, 1 av; with 2 apical bristles. Mid tibia with 3 ad, 2 pd, 1 pv; with 3 apical bristles. Hind tibia with 5 short ad in 1 row, 2 d, 2 pd, 1 av; with 2 apical bristles. Relative length of tibia and 5 tarsomeres of legs LI: 2.6: 1.5: 1.0: 0.7: 0.4: 0.5; LII: 4.0: 2.0: 1.1: 0.9: 0.5: 0.6; LIII: 4.2: 1.5: 1.5: 1.1: 1.1: 0.7. Wing nearly hyaline, tinged brown; veins brown, R4+5 and M1+2 nearly convergent apically. CuAx ratio 0.6. Squama pale yellow with 6 black hairs. Halter mainly pale. Abdomen dark metallic green, with thick pale gray pollinosity, all sternites with bristles. Hairs on abdomen pale, bristles on abdomen black. Male genitalia ( Fig. 17 ): Epandrium longer than wide; inner epandrial lobe small, outer epandrial lobe strong, thickened at tip, with 2 short bristles at tip, 1 long bristle at middle. Surstylus with 1 sharp process and 1 short bristle. Subepandrial process with 2 long thin processes pointed apically. Cercus mainly brown, but yellowish at base, nearly triangular, with several long digitations, with brownish hairs and long black bristles. Hypandrium with 1 inner tooth. Phallus straight. Female. Unknown.

Type material. HOLOTYPE, ♂ labeled: China: Tibet, Motuo, 80k (N29°39'39.3" E95°29'26.5"), 2300 m, collected from bosk near canal, 2013. IX.11, Gang Yao ( CAU). PARATYPES: 2 ♂, same data as holotype.

Distribution. Oriental: China (Tibet).

Remarks. The new species can be separated from other known species of the group by the yellowish base of the male cercus.

Etymology. The specific name refers to the color of cercus.

Figures

FIGURES 16 – 17. Hercostomus flavus sp. nov., male. 16. Antenna, scale bar = 0.2 mm; 17. Genitalia, lateral view, scale bar = 0.5 mm. Abbreviations: epn = epandrium, hyp = hypandrium, ph = phallus, sur = surstylus, lat = epandrial lobe, pos = postgonite, cer = cercus.