Taxonomy: A new species of

A new species of Tricorythodes Ulmer (Ephemeroptera: Leptohyphidae) is described based on nymphs from the Northern Region of Brazil. Tricorythodes rondoniensis sp. n. can be distinguished from other species in the genus by the following characters: wide femora, nearly circular, with the margins covered with very long setae; tarsal claws with 5–6 marginal denticles; terga III–VII with an acute median tubercle; operculate gill ovoid and abdominal colour pattern