Pseudoanthidium Friese is a species-rich genus of wool carder bees (Anthidiini) in the Old World. Pseudoanthidium alpinum (Morawitz, 1873), originally described from the Caucasus Mountains, was chosen as the type species of the genus, although it was insufficiently known. A genetic analysis of the mitochondrial cytochrome c oxidase I (COI) gene (barcoding gene) of new material now allowed the unequivocal assignment of males and females to each other and proved the conspecifity of material from Spain, Greece and Georgia. It turned out that the males with their specialized hairs and combs on the metasomal sterna correspond to the characteristics of Pseudoanthidium s. str., but females with their fully exposed, protruding clypeal apex to the subgenus Royanthidium Pasteels, 1969. A similar combination of male and female characters was also found in three other species of Pseudoanthidium. As the protruding clypeal apex is thus found in both subgenera, this trait proves to be inappropriate for subgeneric classification and indicates that the definition of the subgenus Royanthidium needs to be revised.