Subg. Onthophagus (Serrophorus) Balthasar, 1963

Onthophagus (Serrophorus) Balthasar, 1963, Monogr. Scarab. Aphod. Palaearkt. Orient. Reg., 2: 160. (Type species: Scarabaeus seniculus Fabricius, 1781).

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

1 Head with two horns ............................................................................................................................................................................ 2

Head without horn or just with one horn......................................................... Onthophagus (Serrophorus) senex Boucomont, 1914 2 Pronotum with two strong horns in right angle ............................................ Onthophagus (Serrophorus) seniculus Fabricius, 1781

Pronotum without horn ............................................................................... Onthophagus (Serrophorus) sagittarius Fabricius, 1775