A cladistic analysis of the species groups recognized in Gigantodax Enderlein, using morphological characters, shows that Gigantodax s. lat. is paraphyletic. From a phylogenetic standing Gigantodax must be split into two monophyletic entities: Gigantodax s. str. and the G. cortesi species group. The new genus Pedrowygomyia is proposed for the G. cortesi species group. It presently contains four species, P. cortesi, P. jatunchuspi, P. punapi and P. chacabamba (all new combinations).