Through both natural and experimental rearings, supported by DNA sequence data (CO1, ITS2 and EF1α) as well as examination of material in collections, it is shown that the European nominal taxa Scambus planatus and Scambus ventricosus comprise the spring-emerging generation of Scambus calobatus, the typical form of which occurs as adults in late summer and autumn. The "planatus" form is shown to be the teneral (unhardened) version of the "ventricosus" form. The following synonymies are proposed: Scambus calobatus (Gravenhorst, 1829) = S. planatus (Hartig, 1838), syn. n. = S. ventricosus (Tschek, 1871), syn. n. Molecular data point to incidental natural rearings of a further two species, represented by single specimens.