Key to the species of Badistemon Yeo & Ng, 2007

1. Suture between male thoracic sternites s3/s4 is prominent; sixth pleonal somite ca. 2.5 times wider than median length; telson elongated, distal end narrowing; G1 subterminal segment distal part relatively broad, slightly narrower than basal width, terminal segment relatively shorter, ca. 0.32 times than combined length of subterminal segment and flexible joint (Fig. 6 A–C, 8 A–C; Yeo & Ng, 2007: fig. 4. a–e)........................................ B. turgidulum (Alcock, 1909) (Myanmar)

- Male thoracic suture between s3/s4 is not prominent, represent as a small depression in lateral margin of sternites; sixth pleonal somite note more than ca. 2 times wider than median length; telson elongated, distal end narrowing; G1 subterminal segment distal part neck-like, abruptly narrower than basal width, terminal segment relatively long, more than ca. 0.40 times than combined length of subterminal segment and flexible joint........................................................ 2

2. Cervical groove prominent, regions distinct (Fig. 7A), male telson as long as broad (Fig. 7C), G1 terminal segment sub-cylindrical, tip truncated (Fig. 8 D–F; Wood–Mason, 1871: pl. 14, fig.7)..... B. pealianus comb. nov. (Assam & Mizoram, India)

- Cervical groove superficial, regions not distinct (Fig. 2A), male telson broader than long (Fig. 2 C), G1 terminal segment conical, tip pointed (Fig. 4 A–D, 5A, B)............................................ B. fulvum sp. nov. (Manipur, India)