Four additional species are included in the genus Hemistephanus: H. villosus (Kieffer) comb. n. and H. colombiensis (Ceballos) comb. n., transferred from Megischus and redescribed, and H. costaricensis sp. n. and H. stenogulatus sp. n., described as new; H. artiosulcatus Aguiar is proposed as a junior synonym of H. villosus Kieffer. The males of H. arctatus, H. colombiensis, H. submaculatus, and H. villosus are described for the first time. Much new or additional morphometric data is incorporated and discussed for these species and for H. carinatus, H. erugatus, H. erythrocephalus, H. limpidipennis, H. orfilanus, H. ruficeps, and H. velutinus. New geographical records are presented for all mentioned species and for H. cylindricus. Errata for publications on Stephanidae are presented. Misidentified males published as H. macrurus by Brullé are assigned to Megischus furcatus. A revised and updated key to species, and an updated summary of morphometric information for all Hemistephanus species, are presented. Photographic illustrations are provided for all new or transferred taxa, and to H. carinatus, H. collarifer, H. ruficeps, and H. submaculatus.
biometry; key; Megischus; Neotropical; Central America
