Revision of the European species of Euplectrus Westwood (Hymenoptera, Eulophidae), with a key to European species of Euplectrini

The European species of Euplectrus Westwood are comprehensively treated for the first time, using a combination of morphological and DNA data (CO1, the barcode). Ten species are included, seven already described: E. bicolor (Swederus), E. flavipes (Fonscolombe), E. intactus Walker, E. liparidis Ferriere, E.maculiventris Westwood, E. nigriceps Ferriere, E. phthorimaeae Ferriere, and three new species: E. carinifer sp. n., E. geometricida sp. n., E. pallidigaster sp. n. To stabilize the nomenclature a neotype is designated for E. bicolor. Euplectrus intactus is removed from synonymy under E. bicolor and E nigriceps from synonymy under E. platyhypenae Howard, and both are re-established as valid species. Several host records are given and presented in a table, and new geographical records are introduced for previously described species. All host records are from exposed Lepidoptera caterpillars and the dominant host groups are Geometridae and Noctuidae. A key including all European species of tribe Euplectrini is presented. Prior to this paper the identification of European Euplectrus species has been difficult and misidentifications have probably been common. Existing host and geographical records in the literature must therefore be treated with great care.