Key to males of the genus Cryptochironomus in China

1. Gonostylus widened towards the apex.....................................................................2

- Gonostylus not widened towards the apex................................................................. 3

2. Tergite IX with a pointed projection at each side................................... C. protuberans Yan & Wang sp. n.

- Tergite IX without a pointed projection................................................... C. digitatus (Malloch)

3. Anal tergite bands not fused in the middle.................................................................. 4

- Anal tergite bands fused in the middle.....................................................................5

4. Inferior volsella with two digitiform projection (Fig. 1 B) bearing 1 strong seta respectively....... C. albofasciatus (Staeger)

- Inferior volsella not branched in its distal part, bearing 3 strong setae apically...................... C. defectus (Kieffer)

5. Tarsi 1 of mid and hind legs yellow green without spot....................................................... 6

- Tarsi 1 of mid and hind legs yellow green with dark brown mark at base................... C. maculus Yan & Wang sp. n.

6. Superior volsella short, more or less globular or thumb like; anal point parallel-sided or slightly spatulate apically.........7

- Superior volsella long, cylindrical; anal point slightly swollen apically......................... C. supplicans (Meigen)

7. Scutellum with 6–10 setae; superior volsella more or less globular; frontal tubercles moderately big... C. fulvus (Johannsen)

- Scutellum with 17–26 setae; superior volsella thumb like; frontal tubercles minute................... C. rostratus Kieffer