Taxonomic revision of two species of Aphelonyx (Hymenoptera: Cynipidae: Cynipini) described in Japan

Abstract Two species of oak gall wasps originally described as members of the genus Aphelonyx in Japan are revised. We propose that Aphelonyx crispulae (original spelling: Aphelomyx crispulae Mukaigawa, 1920, syn. nov.) is synonymous with Andricus hakonensis (Ashmead, 1904), and that Aphelonyx glanduliferae (original spelling: Apelomyx glanduliferae Mukaigawa, 1920) is transferred to Heocynips as Heocynips glanduliferae (Mukaigawa, 1920), comb. nov. All validated members of Aphelonyx are now restricted to three species found in the western Palearctic region. Additionally, three cynipid species are revised. Neuroterus orbis Monzen, 1954, syn. nov. is synonymous with A . hakonensis . Andricus squama Monzen, 1953, syn. nov. and Heocynips furvoaurantius Tang, Nicholls and Stone, 2020, syn. nov. are synonymous with H . glanduliferae . Most of oak gall wasps exhibit a heterogonic life cycle, in which not all diagnostic features of a certain genus are necessarily valid for both sexual and asexual generations within the genus. Although the genus Heocynips was established based solely on the asexual generation, its sexual generation is revealed for the first time.