Few political areas in North America offer so much in the way of interest and instruction to the student of the geographical distribution of bumblebees as the Province of Alberta in western Canada. This is due not only to the fact that extremes in elevation between certain portions of Alberta bring together species of pronounced northern and southern tendencies, a condition duplicated in many parts of western North America, but likewise to the fact that Alberta is a meeting ground of species with decided eastern and western affinities. A somewhat similar state of affairs, though less marked, occurs in the Dakotas as attested by a study of approximately 900 specimens of bumblebees from South Dakota submitted to me for determination by Professor H. C. Severin and recorded by him in the “Sixteenth Annual Report of the State Entomologist of South Dakota,” 1925, pp. 17-20.