The investigation reported in this series was carried out with the object of determining the bark-beetle complex associated with slash accumulated under different cutting methods and the hiolosies, distribution, and abundance of the more important bark-beetle parasites and predators throughout the experimental area. This area is in the region termed by Halliday (1937), the B19 or foot-hills section of the Boreal Forest. The experimental area contained a pure stand of even-aged (80 years) lodgepole pine, Pinus contorta Dougl., var. latifolia Engelm., and is located near Strachan, approximately 20 miles southwest of Rocky Mountain House, Alberta.

During the course of control investigations on the black-headed budworm, Acleris variana (Fern.), a preliminary difficulty occurred in the mass rearing of budworm larvae under laboratory conditions. In the forest the eggs are laid on the needles of hemlock and balsam fir trees in late summer. The young larvae emerge the following spring and migrate to the growing buds where they commence active feeding. Under laboratory conditions, however, cut hemlock twigs shed their needles in a very few days and thus the budworm eggs are shed with the needles and exposed to desiccation.

Surveys of parasites of species of Hylemya that attack cruciferous crops were made in Canada as part of a biological control program against these insects. The most important species are Hylemya brassicae (Bouché), H. floralis (Fall.), and H. planipalpis (Stein.). Though not of primary importance on crucifers, H. cilicrura (Rond.) was often associated with the other species. The geographical distributions of these species in Canada were described by Brooks (1951).

The larch sawfly, Pristiphora erichsonii (Htg.), overwinters in a cocoon in the ground and has an adult emergence period that may last two months. Ecological studies of this insect require information on the number of adults emerging and the seasonal pattern of emergence. Several types of open-bottomed screen emergence cages without traps were tested but the insects caught in such cages were difficult to remove. Also, many of the adults were lost in the vegetation unless the cages were visited more frequently than was practicable. The trap described here, attached to a screen cage, eliminates the objections given above and could be of use to persons interested in insects which emerge from the soil.

In field investigations on the relative resistance of varieties of peas, Pisum sativum L., to the pea aphid, Acyrthosiphon pisum (Harr.), the average number of aphids per terminal growth for 13 years (Maltais, 1937, 1950, 1951, and unpublished technical report, 1950-54) for six varieties was as follows: Perfection, 39.6; Daisy, 32.6; Lincoln, 35.6; Laurier (H-103), 9.8; Champion of England, 11.8; and Melting Sugar, 16.8. In a preliminary investigation by Auclair and Maltais (1950), 11 free amino acids were detected in pea plant extracts by paper chromatography. From a visual comparison of chromatograms, the variety Perfection appeared to contain a higher concentration of most free amino acids than the variety Laurier. This is a report on the quantitative estimation of the free and total amino acid contents of the three susceptible varieties (Perfection, Daisy, and Lincoln) and the three resistant varieties (Laurier, Champion of England, and Melting Sugar) by the method of paper chromatography.

Larvae of the pale western cutworm, Agrotis orthogonia Morr., feed almost entirely below ground, attacking their food plants just below the soil surface. Larval movement and feeding usually occur at the interface between dry and moist soil. They can absorb moisture from the soil and also from the plants on which they are feeding.

In a previous investigation, Jacobson (1952) found that mortality from starvation varied directly with temperature and inversely with the size of larvae when the relative humidity was kept near 100 per cent. This paper is a report on the role of moisture during starvation.

Though various species of the genus Mochlonyx Loew are known to be predacious on mosquitoes, there are only a few records of M. velutinus (Ruthe) (= M. culiciformis (DeG.)) in this role. According to Meinert (1886) the larvae of this species feed on the crustaceans Cypris and Daphnia in Denmark. At Churchill, Manitoba, Hocking et al. (1950) considered it the most abundant chaoborine in both open forest and tundra pools but did not specify its feeding habits. Twinn (1926) and Curtis (1953), however, referred to it definitely as a predator of mosquito larvae.

Freeze-drying has become widely accepted as a means of concentrating and preserving substances without destroying biological activity, and is becoming increasingly important in various entomological and bacteriological studies. The methods and tvpes of apparatus used have been recently reviewed by Harris (1954). The apparatus described in this paper was developed at the Entomology Laboratory, Ottawa, for drying small quantities of insect tissue. It is sturdy and may be easily and cheaply constructed from readily available laboratory supplies with common machine-shop tools.

Eggs of the ichneumonid endoparasite Pimpla turionellae (L.) were observed by Bronskill to develop and hatch in physiological saline solution. This raised the question whether the larvae could be reared on unnatural food. Early attempts (Simmonds, 1944) to rear ichneumonid ectoparasites on nutritive gelatin slopes and raw beef were unsuccessful. Heuristic attempts at Belleville have succeeded in raising a small number on such a food.

On August 15, 1955, during studies on the ecology of caterpillars on cabbage near Carp, Ontario, two species of Lepidoptera were observed in unique association. A final-instar larva of the diamondback moth, Plutella maculipennis (Curt.), bore on its third abdominal tergite an egg of the imported cabbageworm, Pieris rapae (L.) (Fig. 1). The larva appeared to he unaffected by the presence of the egg and when brought into the laboratory spun its cocoon within 24 hours. The egg remained attached to the larval skin, becoming enclosed within the cacoon, and hatched during the prepupal period. The resultant larva tried to free itself from the cocoon for several hours and eventually died.