Key to species of genus Timomenus Burr, 1907 from China (male only)

1 Forceps bases far apart................................................................................. 2

- Forceps bases nearly touching........................................................................... 7

2 Both sides of ultimate tergite without process............................................................... 3

- Both sides of ultimate tergite with ear-form process.................................. T. amblyotus Ma & Chen, 1992

3 Forceps with dorsal and inner teeth........................................................................ 4

- Forceps with inner tooth only........................................................................... 6

4 Antennae unicolorous; abdomen dark brown; forceps straight................................................. 5

- Antennae bicolorous; abdomen yellowish brown, both sides blackish; forceps incurved................ T. bicolor sp. nov.

5 Inner tooth of forceps in distal half...................................................... T. oannes (Burr, 1900)

- Inner tooth of forceps in proximal half............................................. T. komarovi (Semenov, 1901)

6 Forceps with very long inner tooth, obliquely raised................................................ T. bii sp. nov.

- Forceps with shorter inner tooth, not raised.............................................. T. shelfordi (Burr, 1904)

7 Forceps with dorsal tooth.............................................................................. 8

- Forceps without dorsal tooth........................................................................... 10

8 Body reddish brown without brilliant lustre; sides of abdominal tergites 5‒8 without prominent tubercles............................................................................................... T. aesculapius (Burr, 1905)

- Body black with brilliant lustre; sides of abdominal tergites 5–8 with prominent tubercles............................ 9

9 Body with purple lustre; forceps distinctly upcurved in side view............................... T. nevilli (Burr, 1904)

- Body with blue lustre; forceps not upcurved in side view.................................. T. lugens (Bormans, 1894)

10 Forceps with inner flange at base.................................................. T. dilatatus Zhang et al., 1999

- Forceps with inner tooth in half......................................................................... 11

11 Body dark brown; inner tooth of forceps in half............................................. T. pieli Hincks, 1940

- Body reddish brown; inner tooth of forceps in distal half.................................... T. aeris (Shiraki, 1906)