Species of the genus Orcus Mulsant, 1850 are revised, keyed and illustrated. Orcus biroi var. ruficollis Weise, 1902 is regarded as a synonym of Orcus biroi Weise, 1902 new synonym. Lectotypes are designated for Orcus biroi Weise, Orcus biroi var. ruficollis Weise, Orcus cinctus Weise and Orcus nigricollis Weise. Three new species, all from New Guinea, are described: Orcus cordiformis, O. tetrafasciatus, O. viridulus. Orcus carinicus Gorham, O. bipunctatus Gorham and O. quadriguttatus Gorham are removed from Chilocorini and transferred to the genus Sticholotis Crotch (Sticholotidini) (new combinations). Distribution, nomenclatural history and diagnoses are provided for each species.