Parasites of Acrobasis spp. found in the Ottawa, Ont., area are separated by using characters of the parasite remains left in the host cases from which the parasites emerged. Characteristics of the cephalic structures, spiracles and skins of final-instar larvae of 28 species of parasites are described and illustrated in this paper; one species was described and illustrated in an earlier paper (Finlayson 1962); and one species is described from the literature. A record of all known species of Acrobasis parasitized by the species treated in this paper is tabulated.

Of the 21 Nearctic species of Pyrobombus Dalla Torre 11 are known to occur in southern Alberta. Distribution, macrohabitat, microhabitat, and period of nest establishment of the 11 species are compared. The behavioral patterns of camouflaging entrances to underground and false-underground hives, gathering material for nests, constructing first- and succeeding-brood egg cells, producing second-generation colonies, storing honey and pollen and producing wax, superseding intra- and inter-specifically, and mating and hibernating are compared both intra- and inter-subgenerically. Most of the behavioral patterns were common to all southern Alberta species of Pyrobombus; some were common only to certain species indicating a close relationship between these species, and one pattern was common to species in two subgenera but to only 4 of the 11 species of Pyrobombus. Thus, evolutionary trends were indicated. The enemies Psithyrus spp., Volucella bombylans (L.), and inclement weather are discussed.

The effects of sprays of DDT, azinphos-methyl, and Ryania applied to a pear orchard on population densities of insect predators of Psylla pyricola Förster were assessed. The P. pyricola in the orchard were naturally tolerant to DDT and Ryania and highly resistant to azinphos-methyl. DDT eliminated or severely reduced numbers of Deraeocoris brevis piceatus Knight, D. fasciolus Knight, Diaphnocoris provancheri (Burque), and Campylomma verbasci (Meyer). Chrysopa carnea Stephens and C. oculata Say were moderately reduced. Anthocoris antevolens (White) and A. melanocerus Reuter were highly tolerant to DDT. Azinphos-methyl severely reduced numbers of A. antevolens, A. melanocerus, C. verbasci, and D. provancheri. C. carnea and C. oculata were moderately reduced. D. brevis piceatus and D. fasciolus were tolerant to azinphos-methyl. Ryania severely reduced numbers of A. antevolens, A. melanocerus, and C. verbasci; moderately reduced D. provancheri; and did not affect D. brevis piceatus, D. fasciolus, C. carnea, or C. oculata.

In the DDT-treated plots the relative densities of Anthocoris spp. approximately doubled compared with the untreated plots. This was probably due to removal of competition for food by other predator species. Large increases ill the relative densities of Deraeocoris spp. were also observed in the Ryania treatments, probably for similar reasons. Significant increases in the P. pyricola populations in response to removal of predation pressure by the insecticide treatments occurred in the DDT and azinphos-methyl plots bur not in the Ryania plots.

Ventral nerve cord severence in newly emerged females of Tenebrio molitor L. resulted in a rate of oocyte production significantly higher than in normal, mated females and much higher than in intact virgins. This suggests that some nervous, inhibitory factor normally controls oocyte production. Mating partially suppresses this inhibitory mechanism, but the higher rate of oocyte production in females with severed nerve cords indicates that the inhibitory mechanism is exercising some control over oocyte production at all times. A sequence of events in the control of oocyte production in Tenebrio is proposed.

The suitability of a European moth Anaitis plagiata (L.) for the biological control of the weed Hypericum perforatum L. in British Columbia is evaluated. It is concluded that the introduction of the moth is justified as it offers prospects of reducing the weed density without damage to economic plants. A. plagiata is preadapted to dry habitats and ecologically restricted to them. Its high fecundity and two generations a year should enable it to reach an effective population level rapidly and the early spring feeding by the overwintered larvae should damage the weed when it is most vulnerable. It was shown by feeding tests that the larvae are restricted to plants in the genus Hypericum. Furthermore, all the known hosts of the genus Anaitis are restricted to the genus Hypericum which indicates that the insect-host plant relationship is an old and highly stable one. Larval feeding was found to be partly in response to a chemical compound present in the cuticular waxes of the host plant.

Larvae of Pseudosarcophaga affinis auct. nec Fallén readily discriminated between synthetic diets satisfactory for growth and those that had nutritionally important faults. The faults were lack of an essential amino acid, unsatisfactory ratios of essential and nonessential amino acids, and unsatisfactory proportions of the best amino acid mixture relative to glucose levels. Some of these were made to resemble the proportions of amino acids and glucose found by other workers in tissues of aphid-resistant and -susceptible varieties of peas. All the experiments showed that the diets chosen by larvae were those on which they grew and developed best. That larvae can relate the chemical composition of the selected foodstuff with their nutritional requirements may cast some light on varietal resistance of plants or other foodstuff to insects.

Megabombus f. fervidus (F.) queens were successfully hibernated in 1961–62 under artificial conditions that are described in detail. One-half succumbed within 3 days after being removed to conditions allowing resumption of active behavior, and 68.7% perished by the end of 3 weeks. Hibernation and (or) post-hibernation survival are believed to be dependent on the amount of fat bodies metabolized prior to this dispause period. Infertile queens (and possibly large workers) are capable of hibernating. It has been discovered that during hibernation the spermatozoa encyst in the spermatheea of fervidus, and it is probable that this phenomenon is not unusual to most species hibernating under cold conditions.

Barylypa irona, a new species of ichneumon fly from Michigan, is described.

An additional record of the tunnelling habit of Ips plastographus (Leconte) is reported and illustrated and the function of the habit is discussed.

One male of this species was collected in a light-trap on 28 June, 1967 at Chatterton, Hastings County, Ontario. This appears to be the first record of A. thibaulti Dyar and Knab in Canada.