This insect in the imago state closely resembles A psi of Europe, and has been, ans we believe still is, doubtfully regarded as identical by several eminent European entomologists. We thinks, however that a comparison of the larval forms of the two insects will help to dispel any doubts which may be entertained regarding the dissimilarity of the species. The following descriprion of the larva of occidentalis has already appeared in part, in the Annual Report of the Entomological Society of Ontario to the Commissioner of Agriculture for 1870, where it is given.