In tests conducted on the Kenai National Moose Range, Alaska, seudenol and α-pinene attracted more spruce beetles (Dendroctonus rufipennis (Kirby)) than did frontalin and α-pinene, the best previously reported synthetic attractant. Addition of methylcyclohexenone (MCH) to sticky traps baited with spruce logs (Picea glauca (Moench) Voss.) infested with 20 female spruce beetles or to traps treated with seudenol and α-pinene reduced the number of spruce beetles caught by 87% and 99%, respectively. MCH appears to have similar repressive effect on the attraction of spruce beetle populations that differ in their geographic locations and hosts. A total of 179 other scolytids, representing 8 genera and 10 species, were caught by traps; greatest numbers were attracted to treatments containing trans-verbenol and uninfested spruce log sections. Scierus pubescens (Swaine) was recorded from Alaska for the first time. No members of Thanasimus species were caught although they have been consistently present in abundance in similar tests elsewhere.

Bionomics of the stream caddisflies, Ceraclea transversa (Hagen) (= Athripsodes angustus Banks) and Ceraclea ancylus (Vorhies) (= Athripsodes ancylus (Vorhies)) were compared with generalized trichopteran life cycles. The univoltine detritus-feeding C. ancylus has five larval instars and a brief adult emergence period. C. transversa has five larval instars but two distinct cohorts, in which larvae of the first cohort feed entirely on freshwater sponge, overwinter as inactive prepupae, pupate, and emerge the following spring. The second larval cohort feeds on sponge until the onset of gemmulation in autumn, then the larvae must overwinter as active third- or fourth-instar detritus-feeders, pupating and emerging later in the summer than the first cohort. The detritus-feeding C. ancylus larvae have a diurnal feeding cycle. The sand case of C. ancylus and the silk-secreted case of C. transversa differ in shape and composition, although both species initiate case construction using egg mass matrix, silk, and detritus. Emergence, flight activity, sex ratios, and adult survival depart from reported generalizations of caddisfly biology. Neither the validity of generalizing typical life cycles in benthic studies, nor the rationale that congeneric species operate as a functional unit in stream dynamics, is substantiated.

Differential survival, growth, and egg production were obtained for the bertha armyworm, Mamestra configurata Wlk., feeding on four natural host plants and one artificial diet. Highest survival, growth, and egg production were obtained among insects reared on the artificial diet. Foliage of potato was the only food which appeared to lack the nutritive qualities essential for adequate survival, growth, and reproduction. Larvae reared on this plant consumed significantly less food, had a poorer survival, accumulated less reserves in the form of tissue growth, developed into smaller pupae, and produced adults that were less fecund than those reared on other foods. Despite these differences, the approximate digestibility (AD), the efficiency of conversion of ingested food to body tissue (ECI), and the efficiency of conversion of digested food to body substance (ECD) obtained for insects feeding on potato, were very similar to values obtained for insects which were reared on other plants. On each diet a linear relationship was obtained between food consumption and growth.

A technique is described for rearing successive generations of the insect in numbers from 200 to 40,000 continuously without diapause. All components of the diet are commercially available and the principal ingredients are of plant origin. Survival at four stages of development is given and the causes of mortality are discussed. The per cent survival of insects from instar III to pupation times the percentage of perfect female pupae obtained at harvest gives a factor considered to be the best measure of the worth of an artificial diet. The variability of these statistics is shown by frequency distributions obtained in 50 independent tests of the diet. Overall survival of 84% times 73% perfect females gave a diet worth factor of 61. An analysis of rearing costs is presented. Although 15 continuous generations have been reared, egg production of the highly selected strain has not deteriorated.

Differential survival and development rates were obtained for the bertha armyworm, Mamestra configurata Wlk., reared at nine constant temperatures. Eggs and larvae had high survival rates at temperatures ranging from 8 °C to 32 °C and pupae showed good survival between 8 °C and 28 °C. Eggs and larvae did not complete development at 6° and 36 °C; and 32 °C was lethal for pupae. Duration of the egg, larval, and pupal stages decreased as the temperature increased from 8 °C to 28 °C. When duration and developmental rates were plotted against temperatures, the observed points did not differ significantly from curves formulated from the logistic equation 1/y = K/(1 + ea−bx). With a developmental threshold of 7 °C, 82, 356, and 352 accumulated day-degrees above the threshold were required for development of eggs, larvae, and pupae, respectively.

A rearing method, based upon an artificial diet, has proved successful in establishing laboratory colonies of 36 species of the genus Euxoa. The diet is described, along with methods for controlling disease, particularly by the use of antimicrobial agents.

Many of the 36 species of Euxoa have not been reared before and their habits and life histories are little known. The data derived from their development under laboratory conditions and which can be related to seasonal distribution are recorded. Particular emphasis is given to the overwintering stage and to the occurrence of an aestivating stage.

Two regions of esterase isozyme activity have been examined in Euxoa declarata (Walker) and E. campestris (Grote) and in their laboratory-reared hybrids. The two species could be distinguished in terms of one group of isozyme phenotypes although there was a small amount of overlap of phenotypes in one region. Two populations of E. campestris examined could not be distinguished clearly from each other. Canonical analysis was used to compare the two species and the populations within each species and the hybrids obtained by crossing various components of the two species. The generalized distance between the species appeared much larger than between populations; the hybrids appeared closer to the male parent.

The eggs of several species of cutworms of the subgenera Chorizagrotis, Crassivesica, Longivesica, Orosagrotis, and Pleonectopoda in the genus Euxoa Hübner are described. Within the genus eggs are of two main types, those with smooth chorions and those with ridged chorions, but all have the same basic chorionic design. Variations in the degree of ridging and in the detail of the design make the egg useful for species determination, and a key to some species is provided. However, the egg is of little value in distinguishing the subgenera as they are currently constituted.

The shape of plasmatocytes in heat-fixed blood of sixth instar larvae of E. rockburnei was compared with that of the same cells in the two other species of the "declarata group", E. campestris and E. declarata. The data show that the shape, represented as the length/width ratio of mature, fusiform plasmatocytes, can serve to distinguish between populations of all three species. It suggests too that E. rockburnei is more closely related to E. declarata than to E. campestris.

When female Tribolium castaneum (Herbst) were sequentially paired with male T. castaneum and then with male T. confusum Jacquelin duVal, 93% of the eggs hatched after the first confinement but only 58.9% hatched after the second confinement. The reciprocal order of pairing produced 0% hatch after the first week of confinement and 55.2% hatch after the second week of confinement. However, the numbers of progeny produced as a result of both sequences were proportional to the percentage hatch. Thus, T. castaneum females appeared to have mated with, and utilized sperm from, males of both species for egg fertilization.

When T. confusum females were sequentially paired in the same way, reductions in egg hatch and production of progeny did not occur. The females either did not mate with T. castaneum males, or if they did mate, they did not utilize T. castaneum sperm for egg fertilization. Moreover the percentage of egg hatch and the numbers of progeny produced were not affected by the sequential order of males as long as one of them was T. confusum.

The introduced parasite Lophyroplectus luteator Thunberg has spread 305 km in an easterly direction in the 13 years since its release and has dispersed faster in southern Ontario than its host, Neodiprion sertifer (Geoffroy). The prevailing westerly winds were probably an important factor. The limited dispersal from a second liberation is discussed.

Mated females of the aphid parasite Aphidius smithi produced only unfertilized eggs (i.e. sons) for the first 2–3 h after copulation and a variable proportion of fertilized eggs (i.e. daughters) thereafter. As a result, the mean proportion of daughters among the offspring of single females was always less than unity, even in a highly favourable environment; the limiting value of the sex ratio was estimated at approximately 85% females. An argument is presented that in haplodiploid species with a variable and environmentally controlled sex ratio a male-producing mechanism is required to ensure the production of a sufficient number of males for the fertilization of all females.

The European corn borer, Ostrinia nubilalis (Hübner), has two distinct geographical populations in southwestern Ontario. The time required for diapause termination is the main distinguishing feature. This together with different critical photoperiods for diapause induction explains the occurrence of two complete generations in the southern portion and only one in the northern portion of this region.

Recent advances in genetic insect control theory have made it important to investigate the fitness effects of, and isolation procedures for, autosomal translocations. We isolated 57 autosomal translocations in Drosophila melanogaster (Dipt., Dros.). Twenty-one were homozygous-viable and a few of these were almost as viable as wild-types. From data obtained during the isolation of these translocations it appears that those translocations whose heterozygotes produce high levels of unbalanced gametes have the same range of homozygous viabilities as others. We may infer, therefore, that it is possible to use our simple marker-free isolation method to isolate translocations with sufficiently low heterozygote and sufficiently high homozygote fitness to make population replacement practicable.

This is confirmed in population cage competition experiments. It appears that between 5 and 10% of induced marker-free translocations may be useful for population replacement.

When the relative velocity of flies is estimated from the frequency of contact of flies with a given area, the resulting picture of activity is misleading because of time-wasting activities arising from encounters between flies. Prediction of this encounter rate is greatly facilitated by the use of Lloyds (1967) index of crowding, which allows for the effects of the non-random distribution of the flies. Prediction of the number of contacts of flies with an inscribed area within the experimental container, was highly successful when the effects of the non-random locomotion of the flies was included in the model of activity.

Data on the parasitic associations of larval water mites with imaginal aquatic insects are reviewed. Documented associations now are known for larvae of 47 genera of water mites in 23 families representing all seven superfamilies. The particular importance of the nematocerous Diptera, and especially the Chironomidae, as hosts of larval water mites is demonstrated, primarily on the basis of new data. New insights into the evolution of parasitic behaviour patterns in larval water mites are discussed.

On 15 November 1971, during collection of galled balsam fir needles from two experimental plots in Edinburg, Maine, damaged galls were noted. The galls had obviously been torn open (Fig. 1). Since this was not recorded in the literature and damaged galls were numerous, the situation was evaluated.