Key to the subgenera of Cacia Newman, 1842

1 Antennomere 6 with apical spine.............................................................. Pseudocacia

- Antennomere 6 without spine........................................................................... 2

2 Antennomere 4 with apical spine........................................................................ 3

- Antennomere 4 without spine........................................................................... 4

3 Antennomere 3 with apical spine.............................................................. Acanthocacia

- Antennomere 3 without spine................................................................... Spinocacia

4 Antennomere 3 with apical spine................................................................ Cacia s. str.

- Antennomere 3 without spine........................................................................... 5

5 Antennomere 3 with tuft of hairs.................................................................. Pericacia

- Antennomere 3 without tuft of hairs...................................................................... 6

6 Antennomere 3 inflated at the inner side....................................................... Corethrophora

- Antennomere 3 not inflated at the inner side........................................................ Ipocregyes