The spider genus Enna is revised and the five previously known species [E. estebanensis (Simon 1898) (Venezuela), E. jullieni (Simon 1898) (Panama, Colombia), E. minor Petrunkevitch 1925 (Panama, Colombia), E. nesiotes Chamberlin 1925 (Panama) and E. velox O. Pickard-Cambridge 1897 (type species) (Mexico)] are redescribed. Dossenus redundans Platnick, 1993 is transferred to Enna and is redescribed and illustrated. Descriptions of 18 new species include the following: E. baeza (Ecuador), E. bartica (Guyana), E. braslandia. (Brazil), E. bonaldoi (Brazil) E. caliensis (Colombia), E. chickeringi (Honduras), E. colonche (Ecuador), E. eberhardi (Costa Rica, Panama), E. hara (Peru), E. huanuco (Peru), E. huarinilla (Bolivia), E. igarape (Brazil), E. kuyuwiniensis (Guyana), E. maya (Honduras, Panama), E. paraensis (Brazil), E. pecki (Costa Rica), E. riotopo (Ecuador) and E. rothi (Ecuador). The type of E. approximata (O. Pickard-Cambridge), collected in Bugaba, Panama, is based on a juvenile and is considered as a nomen dubium. Similarities in the geographical distributions of species of Enna with the distributions of species in the genera Trechalea and Hesydrus are noted.