A faunistic study of genus Chasmogenus Sharp, 1882 of China (Coleoptera, Hydrophilidae)

Chasmogenus Sharp, 1882 is newly reported from the Chinese Mainland. A new species, C. parorbussp. n., is described from China (Yunnan). Chasmogenus orbus Watanabe, 1987 is reported from Hong Kong, the first record outside Japan. Chasmogenus abnormalis (Sharp, 1890) is reported from the Chinese mainland for the first time. The male genitalia of each species are illustrated. A key to the Chinese species of the genus is provided.