Key to Batraxis females from Hainan
1 Body relative small, less than 1.4 mm (Fig. 3 B)................................................... B. minor sp. n.
- Body relative big, more than 1.5 mm ...................................................................... 2
2 Dorsal surface of body covered with long pubescence (Fig. 2 A)..................................... B. pilosa sp. n.
- Dorsal surface of body shiny, glabrous or sometimes with sparse, short setae..................................... 3
3 Abdomen strongly narrowed at lateral margin near base (Fig. 1 B)................................... B. tibialis sp. n.
- Abdomen smoothly rounded laterally or straight............................................................ 4
4 Protibiae expanded at middle; mesotibiae expanded at basal fourth and apical third,.. metatibiae expanded at basal fourth and apex (Fig. 1 A)............................................................................ B. bicolor sp. n.
- All tibiae thin........................................................................................ 5
5 Head with complete subantennal transverse sulcus, anterior margin of vertexal sulcus margin merging with subantennal transverse sulcus; antennae relatively thick; discal carinae of tergite IV widely separate (Fig. 4 A)............. B. simplex sp. n.
- Head with abrupt subantennal transverse sulcus, lacking vertexal sulcus; antennae relatively. thin, discal carinae of tergite IV relatively close....................................................................................... 6
6 Discal carinae of tergite IV slightly divergent, width between discal carinae 1/3 width of tergite IV (Fig. 3 A).................................................................................................. B. hainanensis sp. n.
- Discal carinae of tergite IV divergent, close at bases, width between discal carinae 1/9 width. of tergite IV at bases (Fig. 2 B)....................................................................................... B. spinosas sp. n.