Key to Chinese species of Tetrabothrus

1 Legs distinctly intramuscular; femora broad................................................................ 2

- Legs normal; femora narrow............................................................................ 3

2 The length of tubus of aedeagus as long as the bulbus, and much narrower than the bulbus. (Yunnan, Guangdong)... T. puezti

- The length of tubus of aedeagus approximately 0.8 time as long as the bulbus, and little narrower than the bulbus. (Taiwan)........................................................................................... T. taiwanensis

3 Elytra approximately less than 0.65 times as long as pronotum (EL/PL<0.65)..................................... 4

- Elytra more than 0.80 times as long as pronotum (EL/PL>0.80)................................................ 6

4 Hind wings slightly longer than elytra (Taiwan)................................................... T. semiapterus

- Hind wings entirely reduced............................................................................ 5

5 Larger body size 6.3–7.0 mm; legs reddish-brown; tubus of aedeagus almost straight and pointed in lateral view (Yunnan).............................................................................................. T. brevalatus

- Smaller body size 3.95–4.56 mm; legs yellowish-brown; tubus of aedeagus curved ventrad at base and pointed at apex in lat- eral view (Xizang).......................................................................... T. xizangensis

6 Forebody distinctly bicoloured........................................................................... 7

- Forebody not distinctly bicoloured, more or less uniformly reddish to dark-brown.................................. 8

7 Pronotum pale-reddish, strongly contrasting with the blackish posterior portion of head and blackish elytra; longitudinal diam- eter of eye nearly thrice as long as postocular part (Northern Sichuan)................................... T. rubricollis

- Pronotum yellowish, different from reddish-brown head and elytra; longitudinal diameter of eye nearly twice as long as pos- tocular part (wide spread)...................................................................... T. japonicus

8 Legs pale-yellowish, apices of the femora weakly to distinctly infuscate..........................................9

- Legs reddish-brown to brown, bases of the femora sometimes paler............................................. 10

9 Apices of the femora very narrowly and indistinctly infuscate; anterior angles of pronotum visible in dorsal view; median lobe of aedeagus 0.45 mm long and with short, strongly angled ventral process; paramere small and with shorter apical lobe (wide spead)...................................................................................... T. inflexus

- Apices of the femora broadly and distinctly infuscate; anterior angles of pronotum not visible in.dorsal view; median lobe of aedeagus 0.50 mm long, and with evenly curved ventral process; paramere larger and with longer apical lobe (Yunnan, North

Sichuan)....................................................................................... T. cavus . 10 Head with obtusely marked posterior angle; bulbus of aedeagus narrow at base and the tubus long and straight in lateral view (Shaanxi)................................................................................... T. chinensis

- Head with transverse posterior angles; bulbus of aedeagus rounded at base and the tubus short and curved in lateral view (Hongkong, Taiwan)........................................................................ T. rougemonti