An analysis of Lysiphlebus Foerster species reared from various field-collected aphid species determined the presence of probably trans-palearctic L. fabarum (Marsh.), L. testaceipes (Cress.) which is an accidentally introduced and established immigrant from North America, and L. koraiensis Stary sp. n., a native species of presumably broader distribution. Both parthenogenetic and biparental populations of L. fabarum were identified in Korea.

Muscaphis stroyani (Smith, 1980) and Muscaphis escherichi (Borner, 1939) were collected from Mt. Baekdu-san, North Korea. Fundatrix and alate emmigrant female of the Korean specimens are described. Host plants and brief biology of each species are discussed and the biometric data for fundatrix and alate emmigrant female are given. A key to species for fundatrix and alate emmigrant female is also presented

Three new species of aphid parasitoids and their host-plant associations are described: Pauesia koraiensis Stary(Cinara cembrae Inouye and C. sp. on Pinus koreaiensis), Pauesia holmani Stary(Cinara sp. and C. watanabei Inouye on Pinus koraiensis, and C. laricis Hartig on larix olgensis) and Pauesia gwangleungensis Stary(Cinara shinjii Inouye on Pinus parviflora).

Three species of Macrosiphum(Unisitobion) are recognized from the Korean Peninsula, among which M.(Unisitobion) sorbi matsumura, 1918 and M.(Unisitobion) perilae(Zhang, 1988), comb. nov. are new to the Korean Peninsula. Morphological characteristics are discussed with the microscopic photos. Two species, M.(Unisitobion) sorbi and M.(Unisitobion) perillae are redescribed. The subgeneric position of each species is discussed. The host plants, brief biology, and a key to all known species of the subgenus are also presented.