Key to of 13 males of Rheocricotopus Brundin from the Sino–Indian Region

1. Tergite IX reduced, the posterior margin of tergite IX almost coincide with the base of anal point...................... 2

- Tergite IX developed, the posterior margin of tergite IX exceed the apex of anal point............................... 6

2. Superior volsella triangular or rounded or absent, relatively small............................................... 3

– Superior volsella longitypical or tooth–like, relatively large.................................................... 5

3. Inferior volsella triangular and hooked........................................... R. (P.) isigadeeus Sasa & Suzuki

- Inferior volsella rounded................................................................................ 4

4. Anal point with 2 lateral setae on each side, inferior volsella double–layered.......................................................................................................................... R. (P.) kurocedeus Sasa

- Anal point with without lateral setae on each side, inferior volsella single–layered........................................................................................................ R. (P.) tobatervicesimus Kikuchi & Sasa

5. Superior volsella longitypical, inferior volsella pointed triangular........................... R. (R.) tamahumeralis Sasa

- Superior volsella tooth–like, inferior volsella rounded.................................... R. (R.) tedorisecundus Sasa

6. Gonostylus with apical pointed triangular crista dorsalis....................................................... 7

- Gonostylus with preapical or middle rounded triangular crista dorsalis or without................................... 8

7. Anal point with 2 lateral setae on each side, inferior volsella rounded, double–layered.... R. (P.) hidakadeeus Sasa & Suzuki

- Anal point with with 5 lateral setae on each side, inferior volsella slightly hooked, single–layered................................................................................................ R. (P.) tokarakeleus Sasa & Suzuki

8. Gonostylus without crista dorsalis.......................................... R. (R.) togapeniculus Sasa & Okazawa

- Gonostylus with crista dorsalis........................................................................... 9

9. Superior volsella with almost right–angle corner............................................................ 10

- Superior volsella with rounded corner or tooth–like or absent.................................................. 11

10. Transverse sternapodeme without oral projections, inferior vosella single–layered.. R. (R.) inaxeyeus Sasa, Kitami & Suzuki

- Transverse sternapodeme with oral projections, inferior vosella double–layered... R. (R.) inaquereus Sasa, Kitami & Suzuki

11. Superior volsella tooth–shaped......................................................... R. (R.) tatequintus Sasa

- Superior volsella rounded or absent...................................................................... 12

12. Inferior volsella foot–shaped, gonostylus with preapical crista dorsalis................... R. (R.) shoufukusecundus Sasa

- Inferior volsella rounded with a small lobe, gonostylus with middle crista dorsalis....... R. (R.) yakulemeus Sasa & Suzuki