Published online by Cambridge University Press: 31 May 2012
The two species described here were discovered during studies on a revision of the Ips of North America. They belong to a group of closely related species composed of Ips tridens (Mann.), I. engelmanni Sw., I. yoboensis Sw., I. pilifrons Sw. and I. sulcifrons Wood. The females in this group have the lower part of the front of the head slightly elevated as in I. yohoensis to very strongly protuberant as in I. tridens. All of them breed in species of spruce. The males of this group are difficult to determine from external characters alone. Descriptions were made under a magnification of 50X, using 100X occasionally.
1 Contribution No. 912, Forest Entomology and Pathology Branch, Department of Forestry, Ottawa, Canada.