Key to species (males) of Rhaphium in China

1 First flagellomere at least 4.0 times longer than wide (Figs 2, 4, 6).............................................. 2

- First flagellomere at most 2.5 times longer than wide (Figs 1, 3, 5)............................................ 12

2 Four dc.............................................................................................. 3

- 5–6 dc............................................................................................. 4

3 First flagellomere 4.3 times longer than wide (Yang et al. 2011, fig. 799); with 2–3 pairs of acr; hairs and bristles on coxae black................................................................. R. apicinigrum Yang & Saigusa, 1999

- First flagellomere 8.2 times longer than wide; acr absent (Yang et al. 2011, fig. 812); hairs and bristles on coxae pale yellow....................................................................... R. sichuanense Yang & Saigusa, 1999

4 Arista inflated apically (Yang et al. 2011, fig. 809).................................. R. parentianum Negrobov, 1979

- Arista normal, not inflated apically...................................................................... 5

5 Cercus unequally bifoliate (Fig. 10)...................................................................... 6

- Cercus not bifoliate.................................................................................... 7

6 First flagellomere 10.5 times longer than wide (Fig. 9); thorax with 8 pairs of acr; surstylus oblanceolate, hypandrium hook- like apically.......................................................................... R. bilobum sp. nov.

- First flagellomere 10.5 times longer than wide (Fig. 13); thorax with 8 pairs of acr; surstylus oblanceolate, hypandrium hook- like apically..................................................................... R. daqinggouense sp. nov.

7 First flagellomere 8.0 times longer than wide (Fig. 18)........................................................ 8

- First flagellomere 6.0 times longer than wide at most......................................................... 9

8 Eight uniseriate acr; cercus nearly triangular, short, not bifurcated (Fig. 19).................... R. neimengense sp. nov.

- 5–8 irregularly paired acr; cercus deeply bifurcated with 2 long lobes (Yang et al. 2011, fig. 816)............................................................................................ R. zhongdianum Yang & Saigusa, 2001

9 Arista black; acr absent; surstylus bifurcated apically (Yang et al. 2011, fig. 802)........ R. furcatum Yang & Saigusa, 2000

- Arista pale yellow with black base; acr present; surstylus not bifurcated apically (Yang et al. 2011, fig. 808)................................................................................... R. palliaristatum Yang & Saigusa, 2001

10 Five dc; surstylus long and thin, without apical incision (Fig. 12)............................................... 11

- Six dc; surstylus short and wide, with apical incision (Yang et al. 2011, fig. 815)................................. 12

11 All coxae yellow; hind tibia yellow; surstylus with long thick hairs apically; cercus long band-like (Yang et al. 2011, fig. 815)

.............................................................................. R. xinjiangense Yang, 1998 - Fore coxa yellow, mid and hind coxae black; hind tibia black; surstylus only with sparse short hairs; cercus long triangular (Yang et al. 2011, fig. 810)......................................................... R. qinghaiense Yang, 1998

12 Fore tarsus specialized................................................................................ 13

- Fore tarsus normal................................................................................... 17

13 Fore tarsomere 1 normal, fore tarsomere 5 with 2 Y-shaped apical bristles and 2 long strong bristles (Fig. 17)................................................................................................. R. dorsiseta sp. nov.

- Only fore tarsomere 1 specialized, other various............................................................ 14

14 Fore tarsomere 1 depressed dorsally but strongly raised ventrally.............................. R. lumbricus Wei, 2006

- Fore tarsomere 1 inflated apically........................................................................ 15

15 7–8 dc; arista longer than first flagellomere................................................................ 16

- Six dc; arista shorter than first flagellomere (Yang et al. 2011, fig. 813)..................... R. sinense Negrobov, 1979

16 Seven dc; fore femur without ventral bristle or ventral bristles irregular, not forming into 1 row; fore tarsomere 2 inflated, mid tarsomeres 4–5 inflated (Yang et al. 2011, fig. 800).................................... R. baihuashanum Yang, 1998

- Eight dc; fore femur with 2 rows of ventral bristles; fore and mid tarsi normal, not inflated (Yang et al. 2011, fig. 804)................................................................ R. heilongjiangense Wang, Yang & Masunaga, 2005

17 Fore femur with 1 row of strong ventral bristles or long ventral hairs (Fig. 1).................................... 18

- Fore femur without distinct ventral bristle or hair.......................................................... 19

18 First flagellomere 2.1 times longer than wide; arista 1.9 times longer than first flagellomere; fore femur with 1 row of long pale yellow ventral bristles as long as width of fore femur; cercus wide but narrow at base and wider onwards, with distinct mar- ginal denticles (Yang et al. 2011, fig. 811)............................................. R. riparium (Meigen, 1824)

- First flagellomere 1.5 times longer than wide; arista 2.8 times longer than first flagellomere; fore femur with 2 rows of long pale yellow bristles longer than width of fore femur; cercus very long, wide at basal half (Fig. 8).... R. apophysatum sp. nov.

19 Fore tarsus specialized, tarsomere 1 with 1 row of strong ventral bristles at basal half, tarsomere 2 inflated apically (Yang et al. 2011, fig. 807c)...................................................................................... 20

- Fore tarsus normal, tarsomere 1 without distinct ventral bristle, tarsomere 2 normal............................... 21

20 Legs mainly dark brown; fore coxa with black bristles and hairs............................. R. micans (Meigen, 1824)

- Legs mainly yellow; fore coxa with light yellow bristles and hairs........................... R. dispar Coquillett, 1898

21 Legs mainly black................................................................................... 22

- Legs mainly yellow................................................................................... 23

22 Hind tibia with 3 ventral bristles; mid tarsomere 1 longer than hind tarsomere 1..................................................................................................... R. wuduanum Wang, Yang & Masunaga, 2005

- Hind tibia without distinct ventral bristle; mid tarsomere 1 shorter than hind tarsomere 1......... R. gansuanum Yang, 1998

23 Body length 3.5 mm, wing length 3.7 mm; acr long; legs mainly yellow, but basal 2/3 of fore coxa and apical 1/3 of hind femur, extreme apex of hind tibia black; mid coxa with clusters of bristles ventrally, mid tibia with 1 av................................................................................................. R. mediocre (Becker, 1922)

- Body length 2.7 mm, wing length 2.2 mm; legs mainly yellow except basal half of fore coxa, mid and hind coxae black, apical 1/3 of hind femur with black spot; mid coxa only with 1 strong outer bristle at middle, mid tibia without any ventral bristle (Fig. 3)................................................................................. bisectum sp. nov.