In the present paper the authors describe the male and female genitalia of various species of Zelurus (=Spiniger). There were not always obtained reliable specific characters, specially in nearly related species. Futhermore there were studied 59 species and subspecies, from Dutch Guiana, Brazil, Peru, Bolivia and Argentine. New locality records and synonymic notes are given and some allotypes are designated. Eight species and two subspecies, from Brazil and Argentine, proved to new to science.