Three new species of Omalodes are described from South America, including descriptions of male and female genitalia. Omalodes (O.) mazuri sp. n. is described from Peru and Bolivia; Omalodes (O.) punctulatus sp.n. from Brazil, and Omalodes (O.) rivus sp. n. from Bolivia and Brazil. This is the first paper with detailed information on the male and female genitalia of the genus, showing a great degree of variation to characterize different species. All three new species can be easily distinguished from other known Omalodes and from each other, on the basis of morphology and male genitalia pattern.