New species and species group in the bee genus Scrapter Lepeletier & Serville, 1828 (Hymenoptera: Colletidae) oligolectic on Oxalis flowers in western South Africa

Six new species of the novel carysomus species group in the genus Scrapter Lepeletier & Serville, 1828 are described: Scrapter oxalensis sp. nov. ♀♂, S. oxalicus sp. nov. ♀♂, S. oxaliphilus sp. nov. ♀♂, S. oxalis sp. nov. ♀♂, S. oxalissimus sp. nov. ♀♂ and S. oxaloides sp. nov. ♀. The female of S. carysomus Davies, 2005 is described here for the first time. A key to all species of this species group is provided. The Scrapter carysomus species group is endemic to western South Africa and females collect pollen exclusively on yellow flowers of the genus Oxalis L. (Oxalidaceae).