Key to the Indian species of the genus Halicyclops Norman, 1903

1. Spine formula 2.3.3.3........................................................... H. (H.) canui Lindberg, 1941

- Spine formula 4.4.4.3......................................................... H. (H.) tenuispina Sewell, 1924

2. Genital double-somite with lateral process, spine formula 3.4.4.3............................................... 3

- Genital double-somite without lateral process, spine formula 3.4.4.3............................................. 4

3. Genital double-somite with long lateral spinous process................................. H. (H.) spinifer Kiefer, 1935

- Genital double-somite with small, blunt lateral process............................... H. (H.) electus Lindberg, 1941

4. Second endopodal segment of legs 2–4 with 1 inner seta..................................... H. (H.) martinezi n. sp.

- Second endopodal segment of legs 2–4 with 2 inner setae..................................................... 5

5. Caudal ramus 1.5 times as long as wide, length-width ratio of leg 4 third endopodal segment 2.2................................................................................................ H. (H.) konkanensis Lindberg, 1949

- Caudal ramus 1.2 times as long as wide, length-width ratio of leg 4 third endopodal segment 1.2..................................................................................................... H. (H.) pilifer Lindberg, 1949