Resumen

The male terminalia of a non-type Diathoneura longipennis (Malloch 1926) specimen, collected in Peru, were dissected and analyzed. The aedeagus and associated sclerites were found to have been fixed at a late stage of protrusion, resulting in a different morphology, when compared to the two previous publications, which were fixed at earlier stages. Consequently, additional details of certain anatomical parts were observed and a better understanding of the aedeagus protruding process was attained. Diathoneura longipennis has been previously identified in San Mateo, Alajuela, Costa Rica (type locality) and Panama, and this specimen represents the first record of this species in SouthAmerica.