Metacosma Kuznetzov, 1985 is briefly reviewed and its affinities within Eucosmini are discussed. A checklist of species is presented, including a species of questionable generic assignment, M. miratorana Kuznetzov, 1988. One new species, M. echinophora Komai, Byun Yamazaki, is described from Japan and Korea. In Japan this species is a minor pest in pine plantations. Its larva bores into needles and buds of pines (Pinus spp.), forming a resin dome as a shelter. Photographs of the adult, the genitalia of both sexes, and the larval habitat, along with line drawings of the wing venation, the larva, and the pupa are provided.
Keywords: Lepidoptera, taxonomy, biology, larva, pupa, minor pest, pine plantation, Pinus, Spilonota group.