Protonolima mantispinoformis gen. et sp. nov. (Neuroptera: Mantispidae) is described from the early Eocene Green River Formation. It likely belongs to Calomantispinae, on the basis of the very distal origin of posterior radius and the basal crossvein between media and cubitus (1m-cu) connecting radius + media and anterior cubitus; if so, it would be the only fossil representative of the subfamily. Protonolima gen. nov. is probably most closely related to the extant American genus Nolima.