Key to the species of the Onthophagus militaris species group (modified from Arrow 1931)

1. Elytra with pale spots or patches......................................................................... 2

- Elytra without pale spots or patches..................................................... O. violaceotinctus Gill

2. Elytra yellow with black markings....................................................................... 3

- Elytra black with yellow or red markings.................................................................. 4

3. Pronotum without tubercles, vertex of head in male with a rectangular lamina in between the paired horns..................................................................................................... O. lemniscatus Gill

- Pronotum with tubercles, vertex of head in male without a rectangular lamina in between the paired horns.................................................................................... O. devagiriensis Schoolmeesters & Sabu

4. Anterior margin of clypeus straight, vertex of male with an emarginate lamina and without horns..... O. tnai Nithya & Sabu

- Anterior margin of clypeus not straight, vertex of male without an emarginate lamina and with a pair of horns............ 5

5. Pronotum without distinct granules...................................................... O. militaris Boucomont

- Pronotum with distinct granules.......................................................................... 6

6. Elytron with two red patches.............................................................. O. madoqua Arrow

- Elytron with four or more yellow patches................................................ O. kchatriya Boucomont