Studies on aquatic insects along the river in Oo Ma Da Mountain Stream in Yo Shi No Gun of Nara, Japan. It had been studied from April in 1973 to April in 1974 by Jae Won, KIM. teacher of biology at Po Sung high school in Seoul, Korea. Of the sample of aquatic insects, the Larvae and pupa and adults belonging to Trichoptera were 65 species and following species were unrecorded by the other authors up to the present. 1. Rhyacphila sp. RJ(Larvae: new mention species) 2. Adults of Rhyacophila sp. RJ are Rhyacophila kuwamurae TSUDA. 3. Adults of Rhyacophila sp. RG are Rhyacophila impar MARTYNOV. syn. Rhyacopthila tacita TSUDA. 4. Adults of Rhyacophila sp. RI are Rhyacophila kisoensis TSUDA. 5, I have known Genitalia sturucture from pupa of Neophilax sp. NC. 6. Apatania sp. AB(Larvae: newly mentioned species) 7. I have known Genitalia structure from pupa of Branchycentrus sp. BB 8. I have known Genitalia structure from female and male pupa of Arctopsyche sp. AB. 9. Moropsyche sp. MA.(Larvae: newly mentioned species), and its Genitalia structure are known. by pupa and adults. I wish to express my deepest thanks to Prof. Matsunae TSUDA of Zoological Institute, Nara women`s University and all other Japanese who have helped me.