Larvae of Pseudaletia unipuncta (Haw.), reared on corn foliage, were found to vary in the rate they were able to feed, grow, and attain maturity. Mortality varied inversely with the rate of food intake. In the fifth and sixth instars, there was a direct linear relationship between rate of food intake and daily growth, and rate of food intake and daily development. A variance of 78 to 96% in final weights of the two stages was explained by the combined effect of initial weights of larvae, food supply, duration of feeding, and food ingested. Fecundity increased with the rate of food intake of the larvae.When P. unipuncta feeds at a high rate, it is able to accelerate development, increase growth, and maintain a high reproductive potential. When the rate of food intake is low, development, growth, and fecundity are reduced for the sake of survival.

A descriptive key based on phenotypic characteristics displayed by cocoons and/or pupae is offered as a tool for identification of primary parasitoids of the armyworm, Pseudaletia unipuncta (Haworth), in eastern Ontario. A second key based on structural differences of the last-instar larval mouthparts and tracheae is offered as a means to differentiate secondary parasitoids associated with the above-mentioned primary forms. Photographs of the cocoons, illustrations of the last-instar larval mouthparts and tracheae, and biological notes on pre-imago habits are included as supplemental criteria for species identification.

The piercing mouthparts of three species of mosquitoes were examined with a stereoscan scanning electron microscope. The structures observed are discussed in relation to existing morphological studies. Two pairs of peg-like organs were seen at the tip of the labrum and sensory-like structures measuring approximately 1.2 μ were shown at the tip of the hypopharynx of all species. Differences were observed in the numbers of maxillary teeth of different species. The stylets of Wyeomyia smithii appear functional despite the belief that this species does not take a blood meal.

The role of exuvial holdfast tubercles located on the tenth abdominal segment of pendant rhopalocerous pupae in relation to cremaster withdrawal is described for the first time. Four phases, leading to the final exposure of the exarate pupa, are outlined together with an explanation accounting for pupal gyrations in discharging the larval exuviae after cremaster fixation.

Measurement of radioactivity immediately after application on house fly puparia was found to be the most accurate measure of the weight of radioactive insecticide applied topically and resulted in precise evaluation of the data. Use of radioactive chemicals and microcoulometric determinations indicates that considerable quantities of DDT-14C, heptachlor epoxide - 14C, and lindane-14C, volatilize from applied surfaces, a factor which should not be neglected during penetration studies. Metabolites of DDT were studied by GLC. Only DDE was obtained from flies which emerged from treated puparia of a DDT-resistant strain. Puparial washing 24 hours after treatment yielded some DDE indicating partial metabolism of DDT to DDE on the surface of the cuticle.

A national survey shows that the merchant grain beetle, Oryzaephilus mercator Fauvel, has been present in Canada since at least 1925 and that it has become firmly established as a household pest of processed cereal products preferably of high oil content, but has not been reported from stored grain. A related species, the saw-toothed grain beetle, Oryzaephilus surinamensis (L.), infests both stored grain and processed cereal products. Illustrations are provided to show the morphological characters by which the two species may be recognized and separated.

Over 50 species of Cerambycidae have been reared on artificial diet, 17 of them from the egg. The method, which is described, has proved useful in reducing rearing time in the production of larvae and pupae for taxonomic purposes. It has also demonstrated the occurrence of diapause in some species of Cerambycidae. Other potentially fruitful lines of investigation, made feasible by this method, are suggested.

Individuals of Copidosoma innocuellae n. sp. are described. Many specimens were reared from larvae of Anacampsis innocuella (Zeller) (Gelechiidae), collected in Canada from New Brunswick (type-locality), Quebec, many localities in Ontario, and Manitoba.

The proposed new subfamily Himalocynipinae based on Himalocynips vigintilis n. gen., n. sp., from Nepal, is described and illustrated. Several unique characters of Himalocynipinae are discussed.

The most suitable temperature for larval development of Aedes vexans Meigen was found to be 25 °C. At this temperature 86% of the larvae survived and pupated in 7 days. At 10°, 15°, 20°, and 30 °C larval development time was 46, 22, 10, and 8 days and survival rates were 17, 56, 74, and 71%, respectively. At 5 °C mortality was 100% in the first-instar stage, the last larva dying 12 days after hatching. Adults emerged in 2 to 5 days after being transferred into water at 25 °C, males emerging 2 days before the females.

Eighteen sexual mosaics of S. arcticum including 16 distinct gynandromorphs and 2 apparent intersexes are described. These were discovered among 41,615 normal females from Athabasca, Alberta. Male and female terminalia are compared in four specimens possessing duplicates. Four specimens including two presumed intersexes and two which appeared to be normal males were parasitized with mermithid larvae.

The identities of three closely related species, Prosimulium dicum, P. exigens, and P. dicentum, described by Dyar and Shannon in 1927, are clarified. Keys for the separation of the adult, pupal, and larval stages of these species are given. Also presented is a brief review of the literature for each species. A redescription of the female and first descriptions of the male, pupa, and larva of P. dicentum are provided and important taxonomic features illustrated. A lectotype is designated for P. dicum.

A new species, Ibalia gigantea, is described from material received from the Forestry Station in Calgary, Alberta, and from the Canadian National Collection in Ottawa.

A detrimental effect on larval size in Agria affinis (Diptera: Sarcophagidae) varied with the kind, among nine, and with the dietary level of antimicrobial food additives in a synthetic diet; for example, inversely with the level of streptomycin sulphate. This and other factors considered suggest need for some caution in the use of such food additives where normal insect specimens are desired.