Zerconidae

Key to the females of the Nearctic genera of Zerconidae

1. Peritrematal shield with a single pair of setae .....................................................................Monozercon Błaszak, 1984

- Peritrematal shield with more than one pair of setae.................................................................................................... 2

2. Peritrematal shield with two pairs of setae................................................................................................................... 3

- Peritrematal shield with three pairs of setae............................................................................................................... 18

3. Peritrematal shield posteriorly truncated...................................................................................................................... 4

- Posterolateral ends of peritrematal shield expanded posteriorly.................................................................................. 8

4. Peritrematal setae p1 short and smooth, p2 elongate and pilose.................................................................................. 5

- Both peritrematal setae short and smooth..................................................................................................................... 6

5. Peritrematal shield narrowly separated from dorsal shield; adgenital sclerites absent.... Mixozercon Halašková, 1963

- Peritrematal shield widely separated from dorsal shield; adgenital sclerites present............ Zercon C. L. Koch, 1836

6. Ventri-anal shield divided into three lobes by a pair of deep lateral incisions.................. Macrozercon Błaszak, 1976

- Ventri-anal shield without lateral incisions................................................................................................................... 7

7. Peritrematal shield narrowly separated from dorsal shield; ventri-anal shield expanded anterolaterally; margin of opisthonotum with seven pairs of setae; dorsal cavities absent............................................ Lindquistas Błaszak, 1981

- Peritrematal shield widely separated from dorsal shield; ventri-anal shield not expanded anterolaterally; margin of opisthonotum with eight pairs of setae; dorsal cavities present and conspicuous ................... Bledas Halašková, 1977

8. Peritrematal setae approximately uniform, both short and smooth.............................................................................. 9

- Peritrematal setae diverse in form.............................................................................................................................. 11

9. Posterolateral ends of peritrematal shield free ........................................................................... Bakeras Błaszak, 1984

- Posterolateral ends of peritrematal shield fused to ventri-anal shield........................................................................ 10

10. Adgenital sclerites present, with two pores ........................................................ Blaszakiella Sikora & Skoracki, 2008

- Adgenital sclerites absent, only a single opening of gv2 present....................................... Microzercon Błaszak, 1976

11. Peritrematal setae p1 pilose, p2 short and smooth...................................................................................................... 12

- Peritrematal setae p1 short and smooth, p2 longer..................................................................................................... 15

12. Posterolateral ends of peritrematal shield connected to ventri-anal shield........................ Cosmozercon Błaszak, 1981

- Posterior ending of peritrematal shield free................................................................................................................ 13

13. Peritremes extremely long, reaching beyond the insertion of p2....................................... Echinozeron Błaszak, 1976

- Peritremes medium-sized, not reaching the level of p2.............................................................................................. 14

14. Posterolateral ends of peritrematal shield separated by a narrow slit, as a pair of free ventro-lateral shields; margin of opisthonotum with nine pairs of setae...................................................................................... Krantzas Błaszak, 1981

- Free ventro-lateral shields absent; margin of opisthonotum with eight pairs of setae.......... Allozercon Błaszak, 1984

15. Margin of opisthonotum usually with 16 pairs of setae .................................................. Caurozercon Halašková, 1977

- Margin of opisthonotum with eight pairs of setae...................................................................................................... 16

16. Adgenital sclerites present ................................................................................................... Hypozercon Błaszak, 1981

- Adgenital sclerites absent........................................................................................................................................... 17

17. Peritrematal setae p2 smooth; one pair of adgenital gland openings present; ventri-anal shield with 17 setae (Vl1 present) ........................................................................................ Paleozercon Błaszak, Cokendolpher & Polyak, 1995

- Peritrematal setae p2 pilose; adgenital gland openings absent; ventri-anal shield with 15 setae (Vl1 absent)............. .................................................................................................................................................... Boreozercon gen. nov.

18. Peritrematal shield posteriorly truncated .................................................................... Skeironozercon Halašková, 1977

- Posterolateral ends of peritrematal shield expanded posteriorly................................................................................ 19

19. Setae p1 and p2 pilose; adgenital sclerites and gland openings absent .....................................Aspar Halašková, 1977

- Setae p1 and p2 smooth; 2–3 pairs of adgenital gland openings on conspicuous adgenital sclerites present............ 20

20. Posterior margin of opisthonotum with six pairs of setae .................................................. Parhozercon Błaszak, 1981

- Posterior margin of opisthonotum with seven pairs of setae .............................................. Parazercon Trägårdh, 1931