Résumé
ABSTRACT Onega comprises nine valid species distributed in South American countries, Bolivia, Colombia, Ecuador, Paraguay and Peru, commonly at high altitudes. The genus has as diagnostic characteristics the transition crown-frons with transversal carina; crown and superior portion of frons with concavities; pronotum wider than transocular width of head; and paraphysis, when present, as a median esclerite. The present paper describes Onega musa sp. nov., from Ecuador and Peru, which can be distinguished from other Onega species by: body mostly yellow, with brown maculae distributed on dorsum; posterior margin of male pygofer serrate, with long microsetae on the basiventral margin; aedeagus with shaft bisinuate with dorsal acute preapical process; female sternite VII with posterior margin slightly convex; and first valvula of ovipositor with 38 noncontiguous teeth. Intraspecific morphological variations are discussed.