Key to the species of Zygoneura (Palaearctic and Oriental regions, male)

(Mamaev 1968, 1976, 1985; Mohrig et al. 1990; Yang & Zhang 1990; Sasakawa 1997; Menzel & Mohrig 2000; Rudzinski 2005)

1. Flagellomere neck 1/2 as long as the body. The base of M1 weakly bowed (subgenus Allozygoneura) ...................... 2

- Flagellomere neck nearly as long as the body. The base of M1 strongly bowed .......................................................... 3

2. Gonostylus with two megasetae ................................................................................................................ Z. petasitidis

- Gonostylus with five megasetae ..................................................................................................................... Z. calthae

3. Setae long subequal in length on flagellomeres (Fig. 3 A). Ventral mesial margin of gonocoxa with two groups of weak setae (Fig. 3 E). Gonostylus with 2–3 megasetae (subgenus Zygoneura)............................................................ 4

- Setae mostly short on flagellomeres, except a longer row near the flagellomere neck (Fig. 1 A, 2A). Ventral mesial margin of gonocoxa with two distinct groups of setae (Fig. 1 E, 2E) Gonostylus with two megasetae (subgenus Pharetratula)................................................................................................................................................................. 7

4. Gonostylus with two megasetae ................................................................................................................... Z. sajanica

- Gonostylus with three megasetae ................................................................................................................................. 5

5. Gonostylus oblong, not attenuated at apex (Fig. 2 F).................................................................................................... 6

- Gonostylus oval, attenuated at apex (Fig. 3 F). ............................................................................... Z. occidens sp. nov.

6. Gonostylus with two megasetae arising from apical forth and another megasetae at the apical third of the gonostylus ...................................................................................................................................................................... Z. sciarina

- Gonostylus with one short megaseta arising from apical forth and two other long megasetae at the apical third, close to each other ................................................................................................................................................... Z. mohrigi

7. The two megasetae close to each other on gonostylus, both at the subapical or middle part....................................... 8

- The two megasetae widely apart on the gonostylus, with the distance at least longer than the length of the megasetae .................................................................................................................................................................................... 10

8. The two megasetae of the gonostylus at the subapical part are subequal in length...................................................... 9

- The two megasetae of the gonostylus at the middle part are of unequal in length (Fig. 1 F) ......... Z. disparilis sp. nov.

9. Gonostylus with megasetae on long dorsal lobe, about two times as long as the megasetae .................... Z. flavicornis

- Gonostylus with megasetae on short dorsal lobe, nearly as long as the megasetae ....................................................... ......................................................................................................................................................................... Z. bidens

10. Gonostylus stout, with two megasetae subequal length ............................................................................................. 11

- Gonostylus slender, with two megasetae of unequal length (Fig. 2 F)................................................ Z. longa sp. nov.

11. Gonostylus with megasetae at the apical third and middle parts .............................................................. Z. transferata

- Gonostylus with megasetae at apical third and basal parts......................................................................................... 12

12. Ventral mesial margin of the gonocoxa with pair of distinct lobes. Gonostylus with two megasetae near the dorsal side ........................................................................................................................................................ Z. subdivergens

- Ventral mesial margin of gonocoxa without distinct lobes. Gonostylus with two megasetae near the ventral side ...... .................................................................................................................................................................... Z. divergens