The tadpole of Melanophryne carpish is described based on two specimens found in an arboreal, water-filled bromeliad in humid montane forest at 2,870 m in the eastern Andes of northern Peru (Departamento de San Martı´n). It differs from all known New World microhylid tadpoles in having unpigmented, keratinized, jaw sheaths. The lower labium is expanded and platelike. The body is depressed with eyes located dorsally, and the spiracle is ventral. The presence of jaw sheaths suggests that the larvae might feed while undergoing development in aerial plants. The tadpole of Nelsonophryne aequatorialis is described based on a series of 17 specimens in Gosner Stages 37–42, which were found in a water canal in a pasture at 2,535 m in southern Ecuador (Departamento de Azuay). These tadpoles lack jaw sheaths and have a ventral spiracle with medial subdivision evident anterior to the gut. The tadpoles of M. carpish and N. aequatorialis are compared to one another, as well as other microhylid larvae. The nature of characters used to describe microhylid larvae, especially their mouthparts, is discussed and clarified.