2005 年 10 巻 1 号 p. 27-36
Three similar species of water mite in the subgenus Hygrobates (genus Hygrobates) are reported from middle Honshu, Japan. These include two recently described lacustrine species, Hygrobates (Hygrobates) biwaensis Tuzovskij, 2003 and H. (H.) rarus Tuzovskij, 2003, which are known only from Lake Biwa, and one new fluvial species, H. (H.) capillus sp. nov. The new species is distinguished from the other two by the truncate P-2 ventral projection; the female genital plates being longer than the genital opening and extending to the post-genital sclerite; the anterior border of the flat male genital plate; and the larger body size (408-603μm). Two or three setae are confirmed to be present on the female pre-genital sclerites in the three species reported herein; this character state has never so far been recorded in any member of this subgenus.