THE UNIVERSITY OF KANSAS SCIENCE BULLETIN Vol. 54, No. 1, pp. 1-23 November 15, 1989 The Tribe Osirini, its Scope, Classification, '^^^^-^ ' and Revisions of the Genera Parepeolus and Osirinus IMOV ' (Hymenoptera, Apoidea, Anthophoridae)^ hlARVARD UNIVERSITY A. Roig-Alsina ABSTRACT The limits of the hitherto monotypic tribe Osirini are expanded to include Epeoloides, Parepeolus and three new genera: Ecclitodes, Osirinus and Protosiris. It is suggested that the tribe does not belong in the subfamily Nomadinae, but represents a group of parasites independently derived from pollen-collecting ancestors. A cladistic analysis, a key and descriptions are presented for the genera. For Parepeolus and Osirinus keys to the species, synonymies and descriptions are provided; four new species are described. INTRODUCTION The present paper has three objectives. First, to argue that the monotypic tribes Osirini and Epeoloidini, the hitherto un-placed genus Parepeolus Ducke and the new genera Ecclitodes, Osirinus and Protosiris con-stitute a monophyletic group, the Osirini. Second, to suggest that the tribe so con-stituted does not belong in the subfamily Nomadinae, but is better understood as an independently derived group of parasitic bees within the Anthophorinae. Third, to present an analysis of the relations among the genera of Osirini and revisions of certain genera. This study was triggered by the discovery of some bees, particularly the new species Osirinus lemniscatus, that were obviously re-lated to Osiris Smith by characters of wing venation and genitalia but had a very differ-ent aspect. The build of the body resembled that of Parepeolus and Ecclitodes. Indeed, at first sight 0. lemniscatus looks much like the 'Contribution number 2082 from the Department of Entomology, University of Kansas, Lawrence.