Hercostomus sinicus Stackelberg, 1934

Qian, Xingyang, Wang, Ning & Yang, Ding, 2022, The genus Hercostomus Loew (Diptera, Dolichopodidae, Dolichopodinae) from Inner Mongolia, China, with the description of two new species, ZooKeys 1118, pp. 119-131 : 119

Hercostomus sinicus Stackelberg, 1934

Figs 7 , 11

Hercostomus sinicus Stackelberg, 1934: 174. Type locality: China: "Dyn-uan-in, Nord-Alashan".

Diagnosis.

Postpedicel 1.3 times longer than wide, sharp at tip. Fore tarsomeres 1-3 relatively thin, tarsomeres 4-5 weakly thickened, tarsomere 4 dark brown, tarsomere 5 white. Male cercus long strip-like, geniculate, apical half with long marginal bristles hook-like apically.

Description.

Male (Fig. 7 ). Body length 3.1-3.2 mm, wing length 3.0-3.2 mm.

Head metallic green with pale grey pollinosity. Hairs and bristles on head black, but middle and lower postocular bristles and posteroventral hairs yellow. Antenna black; postpedicel nearly square, 1.3 times longer than wide, sharp at tip; arista black with short hairs, basal segment 0.2 times as long as apical segment. Proboscis brownish yellow with brownish yellow hairs; palpus blackish with brownish yellow hairs and 1 blackish apical bristle.

Thorax metallic green with pale grey pollinosity. Hairs and bristles on thorax black; 6 irregularly biseriate acr slightly long and strong, 6 long strong dc. Scutellum with 2 pairs of sc, basal pair hair-like. Propleuron with yellowish hairs and 1 bristle on lower portion.

Legs mostly yellow. Fore coxa yellow, mid coxa blackish, hind coxa brownish yellow; fore tarsomere 4 dark brown, tarsomere 5 white; mid and hind tarsus brown or dark brown from tip of tarsomere 1 onwards. Fore tarsomeres 1-3 relatively thin, tarsomeres 4-5 weakly thickened. Hairs and bristles on legs black, but some hairs and bristles on coxae yellow; mid and hind coxae each with 1 outer bristle; mid and hind femora each with 1 preapical bristle. Fore tibia with 1 ad, 2 pd and 3 apical bristles (apico-ventral bristle brown, 1/4 as long as tarsomere 1); mid tibia with 2-3 ad, 2 pd and 4 apical bristles; hind tibia with 2 ad, 3 pd and 4 apical bristles (including 1 subapical pd). Relative lengths of tibia and 5 tarsomeres of legs LI: 2.25: 1.1: 0.85: 0.6: 0.35: 0.3; LII: 2.75: 1.45: 0.8: 0.65: 0.4: 0.3; LIII: 3.2: 0.9: 1.2: 0.7: 0.5: 0.3. Wing nearly hyaline, veins dark brown; R4+5 and M1+2 distinctly convergent apically; CuAx ratio 0.4. Squama yellow with brown hairs. Halter yellow.

Abdomen metallic green with pale grey pollinosity except hypogygium brownish yellow at tip. Hairs and bristles on abdomen black. Male genitalia (Fig. 11 ): Epandrium distinctly longer than wide; epandrial lobe weakly bulged. Male cercus long strip-like, geniculate, apical half with long marginal bristles hook-like apically. Hypandrium irregularly branched, right process short, left process long and hook-like.

Female. Body length 3.2-3.5 mm, wing length 3.0-3.2 mm.

Specimens examined.

2 males, China, Inner Mongolia, Tongliao, Daqinggou , 180 m, 2014.VII.22, Ning Wang & Ding Yang (CAU) .

Distribution.

China (Inner Mongolia).

Remarks.

This species is redescribed with illustrations of male genitalia for the first time.

Figures

Figure 11. Hercostomus sinicus Stackelberg, 1934, male genitalia, lateral view. Abbreviations: hyp = hypandrium, epan = epandrial lobe, cer = cercus. Scale bars: 0.1 mm.

Figures 6 - 8. Habitus, lateral view 6 Hercostomus shennongjiensis Yang, 1997, male 7 Hercostomus sinicus Stackelberg, 1934, male 8 Hercostomus triangulatus sp. nov., holotype male. Scale bars: 1 mm.