| abstract | Nine species of Hygrobates (Acari: Parasitengona: Hygrobatidae) from Hokkaido, Japan are described or redescribed from newly collected material and historical specimens. Treated herein are eight species in the subgenus Hygrobates, including one new species, H. bibi sp. nov., as well as H. calliger Piersig, 1896; H. foreli (Lebert, 1874); H. japonicus Uchida, 1931; H. longipalpis (Hermann, 1804); H. longiporus Thor, 1898; H. nigromaculatus Lebert, 1879; and H. sokolowi Thor, 1927. Also treated is H. ezoensis Uchida, 1934 in the subgenus Rivobates. A lectotype and paralectotype are designated for H. japonicus Uchida, 1931. Hygrobates (s. str.) heteropalpis Imamura, 1954 is synonymized with H. calliger Piersig, 1896. The name H. ezoensis Uchida, 1934 is resurrected from synonymy with H. diversiporus Sokolow, 1927. Six species previously known from Hokkaido were collected in the study: H. foreli, H. japonicus, H. longipalpis, H. longiporus, H. diversiporus, and H. ezoensis. New records for both Hokkaido and Japan include H. nigromaculatus and H. sokolowi. A species previously recorded from Hokkaido, H. taniguchii Imamura, 1954, was not found in this study. Three new characters are proposed as useful for the taxonomy of the genus Hygrobates: the ratio of the distance between the P-4 ventral setae to P-4 length, the ratio of the length of the longest terminal seta on IV-L-5 to the length of IV-L-5, and the nature of the outer border of the genital plates. |