The classification of species of the Lygus complex has been somewhat unsatisfactory. Many species were assigned to the genus Lygus solely on the basis of superficial characters and many were transferred from one species group to another on the same inadequate basis. In the present paper the characters of the genera and subgenera of the complex are defined.

Study of structures of the internal male and female genitalia revealed characters of considerable taxonomic value. These, taken in conjunction with external taxonomic characters, enable the species of the complex to be classified into 14 genera or subgenera. Among other things, the investigation showed that the economically important “lygus” bugs are not of the genus Lygus Hahn, but of the genus Liocoris Fieber.

Mature larch sawfly drop to the ground and spin cocoons in the moss or duff. The ground snrface of tamarack bogs is usually uneven, and the moss is variable in moisture content. During hot dry weather the moss on the tops of hummocks in dry sites becomes dry, while that in the depressions remains moist. During periods of heavy rain, or in wet sites, the depressions may be filled with water, while the hummocks usually remain above the water.

This investigation was carried out to determine and explain some of the major factors underlying the variability in concentration of certain bark beetles in slash laid down under different cutting systems. Little is known on the life histories and natural control factors of many of the bark beetles inhabiting lodgepole pine (Pinus contorta Dougl. var latifolia Engelm.) and on the effect which different methods of logging have on the insects. Flash outbreaks in lodgepole pine stands frequently result from the breeding of certain bark beetles in slash remaining after logging operations. The opportunity to carry out this investigation was presented to the Calgary Laboratory in 1952, when the Federal Forest Service initiated studies on selectively cut lodgepole pine. This eventually became a co-operative project between the Federal Forest Service, Department of Northern Affairs and National Resources, and the Calgary Laboratories of Forest Zoology and Forest Pathology of the Division of Forest Biology.