Hercostomus, Loew, 1857

Zhang, Lili, Yang, Ding & Grootaert, Patrick, 2008, Mangrove Hercostomus Sensu Lato (Diptera: Dolichopodidae) Of Singapore, Raffles Bulletin of Zoology 56 (1), pp. 17-28 : 18

Key to species (males) of Hercostomus sensu lato from Singapore

1. Wing with grey to brown stigma at end of R 1; R 4+5 thickened from basal quarter onwards ( Figs. 15 , 20 ) ........................... 2

– Wing without stigma; R 4+5 not thickened ............................ 3

2. Stigma elongate, extending beyond start of thickening of vein R 4+5 ( Fig. 15 ); aedeagus with small denticle, in a more basal position ( Fig. 16 ); knee hind femur darkened above .............. .................................................... H. lanceolatus , new species

– Stigma shorter, reaching the level of thickening of vein R 4+5 ( Fig. 20 ); aedaegus with a larger denticle in a more anteriad position ( Fig. 22 ); knee hind femur not darkened above ...................... .......................................................... H. limosus , new species

3. First flagellomere distinctly elongated, at least 2.0 times as long as wide ( Figs. 1 , 25 ) ............................................................ 4

– First flagellomere not elongated, at most 1.6 times as long as wide ....................................................................................... 5

4. First flagellomere 2.3 times as long as wide ( Fig. 1 ); all coxae blackish; femora blackish except tip of fore and mid femora; cercus with 3 strong bristles on outer margin ......................... ................................................. H. brevidigitalis , new species

– First flagellomere distinctly elongated, 3.0 times as long as wide ( Fig. 25 ), fore coxa yellow, mid and hind coxae brown, femora yellow; cercus without strong bristles on outer margin .......... ............................................................ H. meieri , new species

5. Fore tarsomere 1 ( Fig. 6 ) shortened, concave ventrally with 2 long curved ventral bristles; mid tarsomere 1 ( Fig. 7 ) concave ventrally, with 1 strong ventral bristle near middle and 5 short ventrals basally; cercus large, with short apical tail ( Fig. 8 ) .. ................................................ H. singaporensis , new species

– Fore tarsus normal; cercus triangular, without apical tail ... 6

6. Fore and hind coxae yellow; middle coxa pale brownish with a black anterior stripe; cercus strongly curved, nearly geniculate; aedeagus with 2 inner denticles ( Fig. 12 ) ................................ .................................................... H. brevicornis , new species

– Fore coxa yellow, mid and hind coxae brownish; cercus triangular; aedeagus with 1 inner denticle ( Fig. 30 ) ............... ........................................................ H. plumatus , new species

Figures

Figs. 14–19. Hercostomus lanceolatus, new species, male: 14, antenna; 15, wing; 16, male genitalia; 17, claw-like appendage on aedeagus; 18, ventral lobe of surstyli; 19, dorsal lobe of surstyli.

Figs. 20–24. Hercostomus limosus, new species, male: 20, wing; 21, antenna; 22, male genitalia; 23, cercus; 24, surstyli.

Figs. 1–3. Hercostomus brevidigitalis, new species, male: 1, antenna; 2, male genitalia; 3, cercus. iel, inner epandrial lobe.

Figs. 25–28. Hercostomus meieri, new species, male: 25, antenna; 26, male genitalia; 27, hypandrium and aedeagus, ventral view; 28, cercus.

Figs. 4–10. Hercostomus singaporensis, new species, male: 4, wing; 5, antenna; 6, apex of fore tibia and tarsomere 1 (anterior lateral view); 7, apex of mid tibia and tarsomere 1 (posterior view); 8, male genitalia; 9, cercus; 10, surstyli.

Figs. 11–13. Hercostomus brevicornis, new species, male: 11, antenna; 12, male genitalia; 13, cercus. iel, inner epandrial lobe; oel, outer epandrial lobe.

Figs. 29–32. Hercostomus plumatus, new species, male: 29, antenna; 30, male genitalia; 31, cercus; 32, surstyli.