﻿AbstractThe Chilean water penny genusTychepsephusWaterhouse, 1876 is revised, with descriptions and photographic illustrations of life stages including two larval morphotypes, the pupa of one morphotype, and adults of two species. The pupa ofTychepsephushas not been reported previously.Tychepsephuscekalovicisp. nov.is described, andEctopria(Chilectopria)grandisPic, 1947,syn. nov.is proposed as a new synonym ofTychepsephusfelixWaterhouse, 1876, which is redescribed. Taxonomic treatment of the adults of both species includes images of the habitus of males and females, morphological variation, and male and female genitalia. Males and females are sexually dimorphic. Information on the habitat ofTychepsephusis provided and illustrated with photographs, and the known geographic distribution of the two species is mapped. The occurrence ofTychepsephusin Argentina is reported; therefore, the genus no longer can be considered endemic to Chile. The taxonomic status and geographic distribution in South America of other species ofPsephenidae, particularly members of the subfamilyEubriinae, is reviewed.