When I was revising the genera of the DIPRIONIDAE (Benson,1939), the British Museum had very scanty material of Neodiprion other than of the sole Palaearctic representative of the genus, N. sertifer (Geoffr.). The few North American specimens of the genus, only five females belonging to five species and a few unnamed males, were all ancient specimens in poor condition and pinned so as to obscure the shape of the scutellum. I had therefore to supplement my knowledge of Nearctic Neodiprion by information kindly sent to me by the late Miss Grace Sandhouse, gleaned from specimens in the collections at Washington. Atwood and Peck (1943), in dealing with long series of Canadian Neodiprion, have since found that the shape of the scutellum, as defined in my paper, is rather difficult to interpret and is liable to considerable individual variation.