Resumen
Three new species: Ionthosmittia cuneipenne sp. nov., Orthocladius (Euorthocladius) okinawanus sp. nov. and Parakiefferiella semiovata sp. nov., are described from Okinawa Island, Ryukyus, Japan. In addition to these species, twelve species are newly recorded from this island. Diagnostic characters of Tokyobrillia tamamegaseta (Kobayashi et Sasa) are emended. Pentapedilum yakuabeum Sasa et Suzuki syn. nov. and Polypedilum yakucedeum Sasa et Suizuki syn. nov. are junior synonyms of Ainuyusurika tuberculatum (Tokunaga). Einfeldia kanazawai (Yamamoto) is transferred to the genus Chironomus Meigen and its systematic position is discussed.