The oviparous female and male of Stomaphis betulidahuricae Zhang and Qio, 1999 (Aphidoidea: Lachninae) are described and illustrated in detail for the for the first time. Notes on distribution, biology and host plants are presented. Also, the morphology of the male genitalia are illustrated.

The genus of Stomaphis (Aphididae: Lachninae) is stem or root feeding aphid on trees and can be easily distinguished in having the very long rostrum which extends beyond the length of body. Most of species are monoecious holocyclic without host alternation and attended by ants. Based on body appearance and COI gene sequence, we report a Stomaphis betulidahuricae Zhang and Qio, 1999 (Aphididae: Lachninae) for the first time in Korea, on Carpinus cordata Bl., C. laxiflora Bl., and Acer palmatum Thunb.