Abstract
Although the caddisfly genus Rhyacophila (Trichoptera: Rhyacophilidae) is exceptionally species-rich in southern and southeastern Asia, only 3 species were previously recorded from Borneo, 2 from Sabah and 1 from Sarawak. Examination of caddisfly specimens collected by the 1st author in 1986 through 1989 for the Leiden Museun (The Netherlands) has revealed 4 new species of Rhyacophila. Three of these, R. bintil, n. sp.; R. ladam, n. sp.; and R. lepoh, n. sp. are assigned to the Rhyacophila curvata Group. The 4th species, R. kuku, n. sp., although having affinities with the Rhyacophila lieftincki Group, is currently designated as incertae sedis within the genus. Finally, the female of R. argentipunctella Kimmins is described for the first time, and the species reported from Sabah.