Seven closely related species of pine-feeding webspinning sawflies are segregated into the Acantholyda posticalis group. They are A. posticalis (Matsumura, 1912) with three subspecies, the nominotypical subspecies from Japan (Honshu, Shikoku, Kyushu and Tsushima), A. posticalis koreana n. subsp. from Korea, and A. posticalis pinivora Enslin, 1918,from Europe, Siberia and China, A. xiaoi n. sp. from China (Shandong), A. parki Shinohara et Byun, 1996,from Korea and Russia (Primorskij kraj), A. alpina n. sp. from Japan (alpine zone of northern to central Honshu), A. kojimai n. sp. from Japan (montane to alpine zones of northern to central Honshu), A. pirica n. sp. from Japan (alpine zone of Hokkaido) and Russia (Sakhalin), and A. kumamotoi n. sp. from Japan (northern Honshu). Five new species and one new subspecies given above are described and illustrated. Acantholyda parki is newly recorded from Primorskij kraj and A. posticalis posticalis from Shikoku.