Revision of the genus Arotes Gravenhorst (Hymenoptera: Ichneumonidae: Acaenitinae) from Japan.

Three Japanese species of the genus Arotes Gravenhorst, 1829 are revised. A new species, A. japonicus Ito & Watanabe, sp. nov., is described from the four main islands of Japan. This species can easily be distinguished from congeneric species by the black body without yellow markings and the entirely black hind tibia. Arotes sugiharai Uchida, 1934 is newly recorded from the islands of Kyushu and Tsushima, and the males of this species are described for the first time. The synonymy of A. moiwanus (Matsumura, 1912) and its color variant alboannulatus Uchida, 1928 are confirmed by DNA sequence analysis of the mitochondrial COI gene. The key to the world's species of Arotes proposed by Castillo et al. (2011) is updated and a key to the Japanese species is provided.