Key to Batraxis males from Hainan

1 Body less than 1.4 mm (Fig. 3 B)............................................................. B. minor sp. n.

- Body more than 1.5 mm ............................................................................... 2

2 Dorsal surface of body with bushy, long pubescence (Fig. 2 A)....................................... B. pilosa sp. n.

- Dorsal surface of body shiny, glabrous or sometime with sparse, minute setae..................................... 3

3 Abdomen and elytra bicolorous (Fig. 1 A)...................................................... B. bicolor sp. n.

- Abdomen and elytra concolorous........................................................................ 4

4 Abdomen strongly narrowed at lateral margins near base (Fig. 1 B); profemora protuberant at middle (Fig. 5 F)..................................................................................................... B. tibialis sp. n.

- Abdomen smoothly rounded basolaterally or straight; profemora lacking protuberance............................... 5

5 Mesotibiae with a sharp apical tooth (Fig. 5 E)................................................. B. spinosas sp. n.

- Mesotibiae simple.................................................................................... 6

6 Head with complete vertexal sulcus, anterior margin of vertexal sulcus merging with subantennal transverse sulcus; antennae relatively thick (Fig. 4 A); protrochanters lacking protuberance at ventral margin (Fig. 4 E)............... B. simplex sp. n.

- Head lacking vertexal sulcus; antennae relatively thin (Fig. 3 A); protrochanters expanded ventrally (Fig. 5 K).................................................................................................. B. hainanensis sp. n.