Hercostomus chifengensis, Qian & Wang & Yang, 2022

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 chifengensis sp. nov.

Figs 3 , 9-10

Diagnosis.

Antenna entirely black; postpedicel 1.8 times longer than wide, blunt at tip; basal segment of arista 0.55 times as long as apical segment. Legs entirely black. Wings slightly tinged brown. Male cercus nearly lobate, distinctly longer than wide, with short finger-like marginal processes.

Description.

Male (Fig. 3 ). Body length 3.1-3.2 mm, wing length 3.5-4.1 mm.

Head metallic green with pale grey pollinosity. Hairs and bristles on head black, but middle and lower postocular bristles and posteroventral hairs yellow. Ocellar tubercle with 2 strong oc and 2 short posterior hairs. Antenna (Fig. 9 ) black; postpedicel 1.8 times longer than wide, blunt at tip; arista black, basal segment 0.55 times as long as apical segment. Proboscis brownish with black hairs; palpus black with black hairs and 1 black apical bristle.

Thorax metallic green with pale grey pollinosity. Hairs and bristles on thorax black; 7-8 irregularly biseriate acr short hair-like, 6 long strong dc. Scutellum with 2 pairs of sc and several short marginal hairs, basal pair hair-like.

Legs entirely black. Hairs and bristles on legs black. Mid and hind coxae each with 1 outer bristle; mid and hind femora each with 1 preapical bristle; fore tibia with 3 short ad, 2 short pd and 2 apical bristles; mid tibia with 4 ad, 2 pd, 1 av and 3 apical bristles; hind tibia with 3 ad, 2 pd, 1 short av and 3 apical bristles; hind tarsomere 1 with 1 short v at base. Relative lengths of tibia and 5 tarsomeres of legs LI: 1.8: 0.8: 0.4: 0.3: 0.2: 0.2; LII: 2.7: 1.15: 0.6: 0.5: 0.3: 0.2; LIII: 3.4: 0.85: 1.0: 0.7: 0.45: 0.3. Wing nearly hyaline, slightly tinged brownish; veins brown; R4+5 and M1+2 distinctly convergent apically; CuAx ratio 0.55. Squama yellow with blackish hairs. Halter yellow.

Abdomen metallic green with pale grey pollinosity. Hairs and bristles on abdomen black. Male genitalia (Fig. 10 ): Epandrium distinctly longer than wide, narrowed at tip; inner epandrial lobe relatively small, outer epandrial lobe long finger-like with somewhat swollen tip. Subepandrial process with two long processes branched, one blunt at tip, one sharp at tip. Male cercus large, lobate, slightly shorter than epandrium, distinctly longer than wide, with several short finger-like marginal processes. Hypandrium tubular at tip, with a hook-like projection near middle.

Female. Unknown

Type material examined.

Holotype: male, China, Inner Mongolia, Chifeng, Wangyedian, Binlanggoumen, 1223 m, 2014.VIII.25, Li Shi (CAU). Paratype: 1 male, China, Inner Mongolia, Chifeng, Saihanwula, 1200 m, 2013.VII.24, Xiumei Lu (CAU).

Distribution.

China (Inner Mongolia).

Remarks.

The new species is somewhat similar to H. subrusticus Zhang, Yang & Grootaert, 2008 from Xinjiang of China, but can be distinguished from the latter by the arista located at middle of the dorsal margin of the postpedicel and the male cercus long and narrow. In H. subrusticus , the arista is located at the apical one-third of the dorsal margin of the postpedicel, and the male cercus is relatively short and wide ( Zhang et al. 2008).

Etymology.

The species is named after the type locality Chifeng.

Figures

Figures 2 - 5. Habitus, lateral view 2 Hercostomus beijingensis Yang, 1966, male 3 Hercostomus chifengensis sp. nov., holotype male 4 Hercostomus dilatitarsis Stackelberg, 1949, male 5 Hercostomus neimengensis Yang, 1997, female. Scale bars: 1 mm.

Figures 9, 10. Hercostomus chifengensis sp. nov., male. 9 antenna, lateral view 10 genitalia, lateral view. Abbreviations: hyp = hypandrium, epan = epandrial lobe, cer = cercus, sub = subepandrial process. Scale bars: 0.1 mm.