Abstract
Two new genera and two new species of Mythicomyiinae are described based on material collected in Parque Nacional Serra das Confusões, Piauí state, northeast Brazil, an arid region: Mitinha, gen. nov., type-species M. neri, sp. nov. and Tamanduamyia, gen. nov., type-species T. bandeira, sp. nov. An illustrated key is presented for world Mythicomyiinae genera.