Revision of the asychis species group of Aphelinus (Hymenoptera: Aphelinidae)

Aphelinus (Hymenoptera: Aphelinidae) is a genus of parasitoid wasps that has a long history of use in biological control programs against aphids. Past research shows that species delimitation within Aphelinus is greatly complicated by lack of comprehensive literature and the existence of cryptic species complexes. One of these complexes is the Aphelinus asychis species group. Through the development of a morphological character set, a revision of the Aphelinus asychis species group was conducted. Two new species, Aphelinus sinensis sp. n., and Aphelinus kazakhstanensis sp. n., are described, and the two existing valid species within the asychis group, Aphelinus asychis and Aphelinus semiflavus are redescribed and lectotypes are designated for Aphelinus semiflavus and Aphelinus brevipennis (a junior synonym of A. semiflavus). We also provide a key for identifying species in the asychis group.