ABSTRACT The parasitic ant Leptothorax wilsoni Heinze, 1989 was recorded from New Hampshire, Quebec, and New Brunswick. We report on colonies found in two sites in Jasper National Park, Alberta and in one site south of Glacier National Park, Montana. The host species in the west is apparently the same as in the eastern area. Brachypterous intermorphic and fully alate gynomorphic females were found together in two colonies, confirming that L. wilsoni is a species with queen polymorphism. L. wilsoni workers and host species queens lacked in all colonies, as in the samples from eastern North America
