Ratcliffe, B.C. (1976) A revision of the genus (Coleoptera, Scarabaeidae). 10: 93-204. Héctor Jaime Gasca-Álvarez & Brett C. Ratcliffe (2011) An annotated checklist of the oryctine rhinoceros beetles (Coleoptera: Scarabaeidae: Dynastinae: Oryctini) of the Neotropical and Nearctic realms. Zootaxa 3090: 21-40.