The genus Periphyllus has been revised as seven species in the Korean Peninsula. Recently, Periphyllus hokkaidensis Sorin 1990 is newly discovered on the young shoot of Acer mono subsp. okamotoanum in Ulleung Island. This is the first record found P. hokkaidensis in other areas except Hokkaido, its origin region. As the result of this study, we announce totally eight species in this genus and present description and illustration of P. hokkaidensis with apterous viviparous females.

• Yeyeun Kim(Entomology Program, Department of Agricultural Biotechnology, Seoul National University)
• Seunghwan Lee(Entomology Program, Department of Agricultural Biotechnology, Seoul National University)