Hercostomus

Negrobov, O. P., Kumazawa, T., Tago, T. & Sato, M., 2016, New species of Hercostomus Loew, 1857 (Dolichopodidae, Diptera) from Japan, Zootaxa 4158 (1), pp. 65-80 : 79

Key to species of the genus Hercostomus from Japan (males)

1 Acrostichal setae absent. Fore and mid tarsi with erect ventral hairs. R4+5 sharply curved in apical part. Tarsomeres 4 and 5 of fore tarsus widened ( Fig. 8 I)....................................... Hercostomus zhenzhuristi Smirnov & Negrobov

- Acrostichal setae present, arranged in two rows. Fore and mid tarsi without erect ventral hairs. R4+5 slightly curved or almost straight............................................................................................. 2

2 Postocular setae yellow................................................................................ 3

- Postocular setae black................................................................................. 5

3 Thorax and abdomen with silvery pollinosity. Tarsomeres 4 and 5 of mid leg widened ( Fig. 8 E)................................................................................................ Hercostomus spathulatus sp. nov.

- Thorax and abdomen without silvery pollinosity. Tarsomeres of mid leg not widened.............................. 4

4 Antennae black. Coxae black............................................................ Hercostomus lii Wei

- Antennae mostly yellow ( Fig. 8 G). Coxae yellow........................ Hercostomus flaveolus Negrobov & Chalaya

5 Thorax and abdomen partly yellow....................................................................... 6

- Thorax and abdomen mostly green....................................................................... 8

6 Hypopygium dark ( Fig. 8 D)................................................. Hercostomus nigricollaris sp. nov.

- Hypopygium yellow.................................................................................. 7

7 Only abdominal segments 1–3 partially yellow......................... Hercostomus flaviventris Smirnov & Negrobov

- All segments of abdomen yellow laterally ( Fig. 8 B)................................... Hercostomus falcilis sp. nov.

8 Tarsomere 1 of hind leg with black curved spine ( Figs 1 F, 8A)....................... Hercostomus acutiformis sp. nov.

- Tarsomere 1 of hind leg without curved spine.............................................................. 9

9 Antennae mostly yellow ( Fig. 8 E)............................................ Hercostomus spinitibialis sp. nov.

- Postpedicel black..................................................................................... 10

10 Antennae black. Hind femur without black spot at apex.................... Hercostomus takagii Smirnov & Negrobov

- Scape yellow below. Hind femur with black spot at apex ( Fig. 8 C)................... Hercostomus flavipalpus sp. nov.

Figures

FIGURE 1. Hercostomus acutiformis sp. nov. (A) hypopygium, left lateral view; (B) right cercus, ventral view; (C) hypopygium, ventral view; (D) epandrial lobe, surstylus, postgonite, left lateral view; (E) antenna, lateral view; (F) hind tibia and hind basitarsus, lateral view.

FIGURE 8. Male habitus of Hercostomus species, lateral view. (A) Hercostomus acutiformis sp. nov.; (B) Hercostomus falcilis sp. nov.; (C) Hercostomus flavipalpus sp. nov.; (D) Hercostomus nigricollaris sp. nov.; (E) Hercostomus spathulatus sp. nov.; (F) Hercostomus spinitibialis sp. nov.; (G) Hercostomus flaveolus; (H) Hercostomus flaviventris; (I) Hercostomus zhenzhuristi.