During the course of an investigation carried out some years ago by the writer in the Gaspe peninsula of Quebec, it was discovered that adults of Dendroctonus piceaperda Hopk., Polygraphus rufipennis Kby., Ips perturbatus Eichh., and Ips borealis Sw., cut two sets of tunnels the same season and in some cases hibernated and cut tunnels in the following season. Subsequently, a series of detailed studies on the biology of Canadian barkbeetles has been in progress in field laboratories at Fredericton, N. B., Frater, Ont., Vernon, B.C., and Pender Harbour, B. C.

The following contribution is supplementary and complementary to a more extensive paper recently published in the Annals and Magazine of Natural History. An elucidation of the terminology and definitions of the higher categories employed may be found therein.

Ball's treatment of the genus Philaenus (Proc. Ia. Acad. Sci., VI, pp. 223-226, 1898) contains a discussion of two species. Subsequently a third species described by Stearns (Ent. News, XXIX, 3, 1918) has been added and the genus reviewed by Stearns (Conn. St. Geol. Nat. Hist. Surv. Bul. 34, pt. IV, pp. 224-227, 1923). The present paper includes the description of a new Canadian species with a key to species and varieties based on material represented in the Canadian National Collection.

The collection from which this study was made was obtained through the courtesy of the Entomological Branch, Canadian Department of Agriculture, and was of particular interest in that it not only contiained excellent series of many of the described forms but also several undescribed species. Descriptions of the latter are submitted in the present paper together with notes on some of the others.

This species is very closely related to the following, differing only in a few respects from its description. The male has a small antenna, the third segment 1.25 times length of second. The vibrissae are more closely approximated, being separated by a distance about equal to length of third antennal segment. The prealar bristle is shorter than posterior notopleural bristle. The processes of fifth sternum are not glossy along inner margin. The mid tibia has no anterior bristle, and the hind femur has a proximal series of short posteroventral bristles, none of which are equal in length to breadth of hind femur where situated.