Polypedilum (Tripodura), Townes, 1945

Chen, Jinxian & Zhang, Ruilei, 2021, Two new species of subgenus Tripodura Towns (Diptera, Chironomidae, Polypedilum) from Oriental China, Zootaxa 5072 (2), pp. 191-199 : 196-197

Key to known male imagines of the subgenus Tripodura from China

1. Superior volsella normal Polypedilum type, slender and with an apical projection.................................. 2

- Superior volsella broad, pad-like and without apical projection; or elongate and calvate............................. 3

2. Superior volsella slender and S-shaped................................................... procerum Zhang et al.

- Superior volsella sickle-shaped.......................................................... falcatum Zhang et al.

3. Superior volsella elongate and calvate.................................................................... 4

- Superior volsella broad, pad-like and without apical projection................................................. 7

4. Superior volsella straight and finger-like, with 2 strong transverse setae and a group of slender setae on inner margin, with 1 long outer apical setae................................................................................. 5

- Superior volsella not as above........................................................................... 6

5. Lateral projection of anal point very long, strongly sclerotized and without macrotrichia; cell r 4+5 with 1 spot.................................................................................. nudiprostatum Zhang, Wang & Saether

- Lateral projection of anal point very short and covered with macrotrichia; cell r 4+5 with two spots...................................................................................................... bispinum Zhang & Wang

6. Superior volsella turned inwards apically with 2 long sub-apical setae and 1 apical seta directed medially; anal point with 2 smaller lobe on the side......................................................... mengmanense Zhang & Wang

- Superior volsella toe-like, with 3 apical setae; anal point lanceolate.......................... pollicium Zhang & Wang

7. Tergite IX without lateral projections or shoulders........................................................... 8

- Tergite IX with lateral projections or conspicuous shoulders.................................................. 16

8. Anal point elongation extremely reduced............................................ conghuaense Zhang & Wang

- Anal point elongation normal............................................................................ 9

9. Anal point slender and nearly parallel-sided............................................................... 10

- Anal point broad or apically expanded.................................................................... 11

10. AR 0.80, terminal scale of front tibia oval and apically rounded, superior volsella with 3–5 long apical setae................................................................................................. masudai (Tokunaga)

- AR 1.32–1.66, terminal scale of front tibia triangular and apically pointed, superior volsella with 2 long apical setae......................................................................................... udominutum Niitsuma

11. Wing without markings, anal lobe reduced.......................................... absensilobum Zhang & Wang

- Wing with markings, anal lobe normal................................................................... 12

12. Superior volsella spatulated and inferior volsella with less than 5 setae....................... spathum Zhang & Wang

- Superior volsella pad-like and inferior volsella with more than 5 setae.......................................... 13

13. Terminal scale of fore tibia pointed, distal margin of superior volsella with less than 5 setae, anal point broad, distal part of r 4+5 clear.............................................................................................. 14

- Terminal scale of fore tibia rounded, distal margin of superior volsella with more than 19 setae, anal point spatula-shaped apically, distal part of r 4+5 cloudy........................................................................ 15

14. Cell m 1+2 with 2 distinct markings, superior volsella sub-quadrate with a beak-like inner process, inferior volsella with 9–12 oral setae, AR 1.18–1.38................................................................. japonicum (Tokunaga)

- Cell m 1+2 with 1 marking, superior volsella sausage-shaped without inner process, inferior volsella with 5–7 oral setae, AR 0.53–0.54............................................................................. anningense sp. n.

15. Anal point with 6 setae at base, superior volsella goblet-shaped; gonostylus slender and apex narrowed... cypellum Qi et al.

- Anal point with 2 rows of short setae on dorsal lamella, each row with 8−10 setae; superior volsella pediform; gonostylus moderately broad, apex not narrowed............................................... harteni Andersen & Mendes

16. Anal point slender and almost parallel-sided................................................ unifascia (Tokunaga)

- Anal point broad or apically expanded.................................................................... 17

17. Lateral of anal point very long, superior volsella rectangular................................ enshiense Song & Wang

- Lateral of anal point short, superior volsella not rectangular.................................................. 18

18. Superior volsella trapezium-shaped.................................................. trapezium Zhang & Wang

- Superior volsella not trapezium-shaped.................................................................. 19

19. Anal point with a pair of small lobes to each side........................................................... 20

- Anal point without a pair of small lobes to each side........................................................ 23

20. Superior volsella broad, inferior volsella with more than 10 oral setae.......................................... 21

- Superior volsella much slender, inferior volsella with less than 10 oral setae..................................... 22

21. AR 1.80–1.95, superior volsella with 1 long outer apical seta........................... decematoguttatum (Tokunaga)

- AR 0.61, superior volsella with 2 long outer apical setae................................ napahaiense Zhang & Wang

22. Cell r 4+5 with 1 spot, Cell m 1+2 with one spot confined to middle part, superior volsella not apically bended inwards...................................................................................... jianfengense Song & Wang

- Cell r 4+5 with 2 spots, Cell m 1+2 with one spot stretching from middle part to apical margin, superior volsella apically bended inwards............................................................................... biloborum sp. n.

23. Wing with 1 spot in cell r 4+5............................................................................ 24

- Wing with 2 spots in cell r 4+5 ........................................................................... 26

24. Fore tibial scale rounded apically........................................................ scalaenum (Schrank)

- Fore tibial scale pointed apically........................................................................ 25

25. Gonostylus slender and parallel-sided basal 1/4, lateral projection of anal point slender, marking in cell m 1+2 long and opposite to marking in cell r 4+5 ............................................................. parallelum Zhang & Wang

- Gonostylus not as above, lateral projection of anal point broad, marking in cell m 1+2 long and distal to marking in cell r 4+5.................................................................................... quadriguttatum Kieffer

26. Setae on vein R 4+5 less than 7 and situated distal 1/3 to apex........................... apiculusetosum Zhang & Wang

- Setae on vein R 4+5 more than 15 and situated from basal 1/4 to apex............................................ 27

27. AR more than 1.10, the superior volsella with 6–7 apical setae............................ cochlearum Zhang & Wang

- AR less than 0.80, the superior volsella with 1–3 apical setae.................................................. 28

28. The gonostylus expanded in the middle and bent like a bow............................... arcuatum Zhang & Wang

- The gonostylus not expanded in the middle............................................................... 29

29. The spots in cell m 1+2 dark and cloudy on wing distal margin............................... bilamella Zhang & Wang

- The spots in cell m 1+2 faint and clear on wing distal margin.................................. dengae Zhang & Wang