A new species of Tricorythodes Ulmer (Ephemeroptera: Leptohyphidae) from Minas Gerais, Southeastern Brazil.

Tricorythodes molinerii sp. n. is described and illustrated based on nymphs from southeastern Brazil. The new species can be distinguished from other species of Tricorythodes Ulmer by the following characters: 1) genal projection present; 2) maxillary palp bi-segmented, with short apical seta; 3) pronotum with well developed anterolateral projection; 4) dorsum of fore femora with a transverse row of setae; 5) tarsal claws without marginal denticles and with one submarginal denticle on each side; 6) operculate gills triangular, shaded with black, and with whitish mark in subbasal zone; and 7) very large size.