Seasonal dimorphism in O. ypsilongriseus adults is determined by the photoperiodic conditions perceived during the preimaginal stages. Comparative studies among adults obtained from laboratory studies under short-and-long-day conditions, the lectotype of O. ypsilongriseus, and the holotype of Solubea grisescens (Sailer), led us to consider O. grisescens the equivalent of the hibernating morph of O. ypsilongriseus and, consequently, its junior synonym.