This paper includes 23 species (20 new) from South America, and 1 species (new) from Trinidad. Three subgenera are represented: Bruchiurosigalphus with 4 species, Urosigalphus with 5 species, and Neourosigalphus with 15 species. The known biology and distribution of each species is given, along with complete descriptions. The species are internal parasites of Bruchidae and Curculionidae.