Four new species of the genus Cacopsylla Ossiannilsson are described and illustrated based on adults and fifth instar immatures. Cacopsylla spp. nov. are associated with Malus baccata (L.) Borkh. (Rosaceae), Crataegus pinnatifida Bunge (Rosaceae), Aralia elata (Miq.) Seem. (Araliaceae), Pittosporum tobira (Thunb.) W. T. Aiton (Pittosporaceae) respectively. Short biological notes are provided.

• Geonho Cho(Laboratory of Insect Biosystematics, Department of Agricultural Biotechnology, Seoul National University)
• Seunghwan Lee(Laboratory of Insect Biosystematics, Department of Agricultural Biotechnology, Seoul National University, Research Institute of Agriculture and Life Sciences, Seoul National University)