The formely monotypic Neotropical genus Megalocraerus Lewis is revised to include five species, known from southeastern Brazil to Costa Rica: Megalocraerus rubricatus Lewis, Megalocraerus mandibularis sp. n., Megalocraerus chico sp. n., Megalocraerus madrededios sp. n., and Megalocraerus tiputini sp. n. We describe the species, map their distributions, and provide a key for their identification. Their subcylindrical body form and emarginate mesosternum have previously hindered placement to tribe, although their curent assignment to Exosternini now appears well supported by morphological evidence. Nothing is known of the natural history of the species.
Keywords: Exosternini; Histeridae; Histerinae; Neotropical region; subcortical predator.