Review of the Nearctic and Neotropical genus Atrusca Kinsey, 1930 (Hymenoptera: Cynipidae, Cynipini)

Phylogenetically the genus Atrusca Kinsey forms a very distinct clade; the genus is most closely related to Cynips (= Besbicus), Philonix and Xanthoteras gen rev.. Morphologically, Atrusca most closely resembles Cynips (= Besbicus) and Antron. This study reviews the genus Atrusca including 42 species. Three new synonyms are proposed: Atrusca vanescens (Kinsey, 1930), syn. nov. of Atrusca bella (Bassett, 1881), Atrusca oriunda (Kinsey, 1936), syn. nov. of Atrusca oriens (Kinsey, 1936), and Atrusca vulgata (Kinsey, 1936), syn. nov. of Atrusca vasta (Kinsey, 1936). Two species are transferred to other genera, Atrusca sagata (Kinsey) is transferred to Sphaeroteras and A. clavuloides (Kinsey) is transferred back to the genus Xanthoteras gen. rev., which is here re-established. We provide the re-descriptions of all known Atrusca species, diagnoses, keys to species and information on biology, phenology, and distribution.