Subg. Onthophagus (Colobonthophagus) Balthasar, 1963

Onthophagus (Colobonthophagus) Balthasar, 1963, Monogr. Scarab. Aphod. Palaearkt. Orient. Reg., 2: 164 (Type species: Scarabaeus tragus Fabricius, 1792).

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

1 Head with long lobe-like horn, the base of the horn greatly broadened; pronotum with strongly developed lobe-like horn pointing forward...................................................................................................... Onthophagus (Colobonthophagus) lunatus Harold, 1868 Head without horn or with horn in different shapes; pronotum without horn ...................................................................................... 2

2 Head with a straight ridge; horn(s) not strongly developed and connected with the lobe-like ridge ...................................................... .......................................................................................................... Onthophagus (Colobonthophagus) armatus Blanchard, 1853

Head with a curved ridge, horn(s) strongly developed and not connected with the ridge ...................................................................... ............................................................................................................... Onthophagus (Colobonthophagus) tragus Fabricius, 1792