The type species of Eucosma Hübner (Lepidoptera: Tortricidae: Eucosmini).

Eucosma Hübner is the largest genus in the Tortricidae with more than 290 named species. Historically, there has been confusion about the assignment of species to Eucosma and related genera, a problem which is perpetuated by the lack of a type specimen for the type species, E. circulana Hübner. Here we designate a neotype for E. circulana following analysis of eight North American species having similarities with that taxon. Eucosma circulana and E. gemellana Heinrich are redescribed, the latter being elevated from subspecies to species status. Eucosma paragemellana, new species, is described from specimens previously confused with E. gemellana, and E. fraudabilis Heinrich is reviewed.