Chrysosoma, Guerin-Meneville, 1831

Tang, Chufei, Zhu, Yajun & Yang, Ding, 2019, Sciapodinae from the Himalayan region with description of nine new species from Tibet (Diptera: Dolichopodidae), Zootaxa 4577 (1), pp. 1-28 : 17-18

Key to species (males) of Chrysosoma in the Himalayan region

1 Arista-like stylus very long, as long as or longer than body ( Chrysosoma proliciens group)............................ 2

– Arista-like stylus relatively short, distinctly shorter than body.................................................. 4

2 Postpedicel and arista-like stylus fused, broad and shiny at base and curved back over entire body; 3 strong acr present; costal vein without curled bristles; halter dark brown; cercus brownish, with digitiform dorsal projection nearly as long as large bilobed, clavate ventral arm ( Yang et al. 2011, fig. 94) [ China, India, Nepal] …... Chrysosoma crinicorne ( Wiedemann, 1824)

– Postpedicel triangular with long, curved dorsoapical arista-like stylus as long as body; 5 strong acr present; costal vein with short black, somewhat flattened and curly bristles extending to R 1; halter yellow; cercus yellowish, with short dorsal digitiform projection and large, bilobed clavate ventral arm ( Bickel 1994, fig. 60) [ India].............................. 3 (Walker, 1856)

3 Cercus with short digitations and a large bifurcated ventral arm ….................. Chrysosoma proliciens (Walker, 1856)

– Cercus long digitiform, wide and at apex ( Wang et al. 2014, fig. 4) …... Chrysosoma nyingchiense Wang, Zhu & Yang, 2014

4 Wing with dark brown maculation, continuous along anterior margin, with shallow excavations on posterior margin in both sexes (Becker 1992, fig. 82) ( Chrysosoma vittatum group)..................................................... 5 – Wing hyaline, without maculation ( Chrysosoma leucopogon group in the Himalayan region)........................... 7

5 Mid and hind coxae black; cercus deeply bifurcated with strong bristles apically.................................... 6

– Mid and hind coxae yellow; cercus simple and hairy ( Becker 1922, fig. 83) [ India] … Chrysosoma vittatum (Wiedemann, 1819)

6 Antenna dark yellow except scape blackish; 7 acr present; ventral branch of cercus rod-like, with only 1 pale apical bristle ( Yang et al. 2011, fig. 117) [ China]..................................................... Chrysosoma varitum Wei, 2006

–.. Antenna wholly yellow except postpedicel slightly blackish dorsally; 5 acr present; ventral branch of cercus band-like, bifurcated lightly at apex, with several apical bristles and 1 long, strong dorsal bristle at apical third [ China, India, Nepal]................................................................................. Chrysosoma cupido (Walker, 1849)

7 Arista-like stylus distinctly longer than head and thorax together; legs mainly black; cercus obviously bifurcated ( Yang et al. 2011, fig. 107) [ China, India, Nepal]................................. … Chrysosoma leucopogon ( Wiedemann, 1824)

– Arista-like stylus not or nearly as long as head and thorax together; legs mainly yellow; cercus various................ … 8

8 Mid tarsomere I without spine-like v; cercus with apical incision ( Wang et al. 2014, fig. 2) ….......................................................................................... Chrysosoma furcatum Wang, Zhu & Yang, 2014

– Mid tarsomere I with row of 4–5 spine-like v; cercus without apical incision ( Wang et al. 2014, fig. 6) [ China] ….......................................................................... Chrysosoma spinosum Wang, Zhu & Yang, 2014