Key to species of Zygoneura Meigen from China (modified from Zhang et al. 2010)

1. Flagellomere with body much longer than neck, mostly with short subequal setae on flagellomere body (Fig. 3B). Gonostylus with five megasetae of almost equal size (Fig. 3C) (subgenus Allozygoneura)........ Z. xizangensis Shah & Huang sp. nov.

- Not as above......................................................................................... 2

2. Setae long subequal in length on flagellomeres (Figs 14D, 15B, 16B). Ventral medial margin of gonocoxa with two groups of weak setae (Figs 14C, 15D, 16D). Gonostylus with 2–3 megasetae (subgenus Zygoneura)............................ 3

- Setae mostly short on flagellomeres, except for a longer row near the flagellomere neck (Figs 5C, 6C, 7C). Ventral medial margin of gonocoxa with two distinct groups of setae (Zhang et al. 2010: 42, Fig. 1E). Gonostylus with two megasetae (subgenus Pharetratula)........................................................................................ 5

3. Gonostylus with two megasetae (Fig. 15D).................................................. Z. sajanica Mamaev

- Gonostylus with three megasetae (Figs 14C, 16D)........................................................... 4

4. Gonostylus oblong, not attenuated at apex (Fig. 16D)........................................... Z. sciarina Meigen

- Gonostylus oval, attenuated at apex (Fig. 14C)........................................... Z. occidens Zhang & Wu

5. Gonostylus with two megasetae of almost equal length; one on dorsal side at the apical third region and the other on ventral side near the middle (Fig. 13C)..................................................... Z. yangi Shah & Huang sp. nov.

- Not as above......................................................................................... 6

6. The two megasetae close to each other on gonostylus, both at the subapical or middle part (Figs 5B, 7B, 10C–D)......... 7

- The two megasetae widely apart on the gonostylus, with the distance at least longer than the length of the megasetae (Figs 6B, 8C, 11B)........................................................................................... 10

7. The two megasetae of the gonostylus at the subapical part are almost equal in length (Figs 10C–D).................... 8

- The two megasetae of the gonostylus at the middle part are of unequal length. (Figs 5B, 7B).......................... 9

8. Gonostylus with apex slightly attenuated, the two megasetae are small (Zhang & Yang 1990: 268, Fig. 1E)................................................................................................... Z. bidens (Mamaev)

- Gonostylus with apex not attenuated, the two megasetae are large and tusk-shaped (Figs 10C–D)............................................................................................. Z. motuoensis Shah & Huang sp. nov.

9. Gonostylus with the two megasetae overlap on each other in ventral view (Fig. 5B).............. Z. disparilis Zhang & Wu

- Gonostylus with megasetae parallel to each other in ventral view (Fig. 7B)...................... Z. flavicornis (Mamaev)

10. Gonostylus with megasetae on apical third and middle region (Figs 9B, 9E, 12B).................................. 11

- Gonostylus with sub-apical and sub-basal megasetae (Figs 6B, 8C, 11B)........................................ 12

11. Megasetae relatively short, both at the apical third part of gonostylus (Figs 9B, 9E).... Z. minuscula Shah & Huang sp. nov.

- Megasetae normal in length, one at apical third and the other at the middle part of gonostylus (Fig. 12B)................................................................................................. Z. transferata Rudzinski

12. Gonostylus slender (Fig. 8C)............................................................ Z. longa Zhang & Wu

- Gonostylus stout (Figs 6B, 11B)........................................................................ 13

13. Ventral medial margin of the gonocoxa with pair of distinct lobes. Gonostylus with two megasetae near the dorsal side (Fig. 11B).................................................................. Z. subdivergens (Mohrig & Mamaev)

- Ventral medial margin of gonocoxa without distinct lobes. Gonostylus with two megasetae near the ventral side (Fig. 6B).................................................................................... Z. divergens (Mamaev)