A new cave-dwelling species of Ptiloneuropsis from southeastern Brazil, is here described based on both sexes, illustrated and named as: Ptiloneuropsis krenaki sp. nov. This new species differs from Ptiloneuropsis immaculata Roesler, 1940 and Ptiloneuropsis diamantina Silva-Neto, García Aldrete & Rafael, 2018 in details of the hypandrium and phallosome. In addition to the third new species of the Ptiloneuropsis, descriptions of variation in the fore and hindwings veins are also given. The diagnosis of Ptiloneuropsis is updated, and P. immaculata is redescribed. Furthermore, the first identification key for Ptiloneuropsis species, based on males, is presented.