A new species of the Neotropical genus Auloceromyia Lindner-A. pachypoda nov. sp.-is described and illustrated based on one male from Argentina and twelve females from Mato Grosso do Sul State, Brazil. The male of A. pedunculata Pimentel & Pujol-Luz is described and illustrated for the first time, together with the first description of the female terminalia. A key to the known species of the genus is provided.