A possible new subspecies of Eurytides dioxippus (Hewitson) (Papilionidae) found on Costa Rica's Osa Peninsula is illustrated, together with notes on its appearance and behavior. An undescribed Euptychia (Satyrinae) found on Osa (also other Costa Rican localities and Panama), is also illustrated, together with records and field notes on other interesting Osa captures including the rarely collected Cissia gomezi Singer, DeVries & Ehrlich (Satyrinae).
