Subg. Onthophagus (Gibbonthophagus) Balthasar, 1963

Onthophagus (Gibbonthophagus) Balthasar, 1963, Monogr. Scarab. Aphod. Palaearkt. Orient. Reg., 2: 163 (Type species: Onthophagus atripennis Waterhouse, 1875).

Key to species of Onthophagus (Gibbonthophagus) from Hong Kong.

1 Pronotum with depression or groove the near front .............................................................................................................................2 Pronotum without depression or groove near the front ........................................................................................................................3

2 Pronotum concave and margined; elytra with dark brown spots in interstriae and striped from dorsal view......................................... ................................................................................................................... Onthophagus (Gibbonthophagus) taurinus White, 1844 Pronotum concave but not obviously margined; elytra with dark brown spots but scatterly distributed and not striped from dorsal view................................................................................................. Onthophagus (Gibbonthophagus) luridipennis Boheman, 1858

3 Pronotum and elytra in similar colour, usually yellow brown with dark spot in irregular pattern; pronotum scattered with big punctures ................................................................................................... Onthophagus (Gibbonthophagus) rectecornutus Lansberge, 1883 Pronotum dark brown to black; elytra in light colour; pronotum without dark spot in irregular pattern; pronotum with dense and fine punctures............................................................................................... Onthophagus (Gibbonthophagus) proletarius Harold, 1875