Collections of the adult chironomid midges were carried out by Suzuki on Chichijima and Hahajima, the two major islands of Ogasawara, during the period from April 14 to May 6,1996,by sweeping with insect net during daytime, and with light traps during nighttime. The specimens were preserved in 70% ethanol, and individually mounted in gumchloral solution by Suzuki on slides after digested in alkali and dissected. Only the male specimens were used usually for the species identification. As the results, a total of 21 species were identified, among which only 5 were diagnosed as species in common with the mainland of Japan or elsewhere in the world, and the rest 16 species, including 13 which are described as new species in the present paper, are considered as indigenous to the Ogasawara Islands. A new genus, Hahayusurika, and Paratrissocladius Zavrel, a genus new to Japan, are also recorded in the present paper.
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