Laboratory experiments indicate a diet of quaking aspen is essential to give impetus to a population increase of the large aspen tortrix. The effects of starvation and of five different host plants on larval survival, pupal weights, and adult egg potential are reported.

Chromosonial studies have elucidated phylogenetic relations in Drosophila (White, 1954), culicids (Jucci, 1952) and chironomids (Bauer, 1936, 1945). Since it appeared promising to apply this approach to the Simuliidae, Rothfels and Dunbar (1953) began a cytological survey of the black flies of eastern Canada during the summer of 1951. They found that in this group the giant salivary gland chromosomes provided “a wealth of descriptive morphological detail in their number and gross morphology, in the characteristics of expanded centromere regions, in the location of specific nucleolar sites, in the degree of pairing of constituents, and in the ultimate discernible banding pattern…. Since these features are not functionally related to the external environment, the confusing effects of convergence are minimized, resemblances may be taken to indicate relation, and grouping is possible according to natural affinities” (Rothfels and Dunbar, 1953).

Two types of field bioassays of the relative attractiveness of various pheromone sources to Ips pini were conducted at Wanakena, N.Y., and at Warrensburg, N.Y. In the first test, the numbers and sex ratios of beetles responding to boring males from New York, Idaho, and their F1 and backcross hybrids graded down in the order of "blood relationship." The intermediate attractiveness of hybrids indicates that hybrids produce pheromones of both parents. In the second test, New York males reared in white pine attracted greater numbers of beetles than those reared in red pine and beetles boring in white pine were more attractive than those boring in red pine.

The balsam woolly aphid, Chermes (Adelges) piceae Ratz., is widely distributed in Europe and North America. It infests many species of Abies (true firs) and may be found attacking its hosts at elevations from near sea level to timberline (5,000 to 6,000 feet). Because of the great range of environments inhabited by the balsam woolly aphid, its biology differs considerably from one region to another. Perhaps the most variable feature in its biology is seasonal history. Karafiat and Franz (1956) reported three generations per year in central Europe, whereas Varty (1956) noted two and sometimes a partial third generation in Scotland. Balch (1952) found only two generations in the Maritime Provinces of Canada, but Amman noted three and sometimes a partial fourth generation in southeastern United States.

Continuous trapping on the bark surface of trees infested with Dendroctonus brevicomis LeConte was carried out during six beetle generations from June 1969 to November 1971, at the University of California’s Blodgett Forest Research Station in the central Sierra Nevada mountains. Significant linear correlation was found between the density of D. brevicomis trapped on the surface of infested trees and the initial within-tree beetle densities. In the first beetle generation, mass arrival was rapid and intense (averaging 1167 beetles per 2.7 sq. dm of trapping surface on each tree, during a mean of 8.8 days). The arrival patterns during this generation were quite consistent between trees. During the second generation, mass arrival was prolonged over a mean of 19.4 days and fewer beetles were trapped ( per 2.7 dm2 of trapping area per tree). The patterns of arrival were more variable during this second generation. In generation 1, with the exception of one tree, the beetles were distributed equally at the three trapping heights (4.5, 7.5, and 10.5 m). In generation 2 they were more abundant on the traps at the lower portions of the tree.

A single 7.5-min injection of 0.6 p.p.m. of methoxychlor into the North Saskatchewan River eliminated 100% of instars 3 to 6 inclusive of the larvae of Simulium arcticum Mall, from sites 40 and 80 km downstream, 91% at 121 km, and 66% at 161 km. Ninety-six per cent of the larvae less than 1 mm long were removed from the 161-km site. Plecoptera larvae were similarly affected. Chironomidae, Ephemeroptera, and Trichoptera were least affected.

The treated portion of the river was rapidly repopulated by insect larvae. None of the pretreatment taxa disappeared and in fact many new ones appeared, during the 10 weeks immediately following the treatment. In all four sites examined in the treated portion of the river, population densities of Chironomidae larvae larger than 1 mm long equalled or surpassed the pretreatment densities within 1 to 3 weeks, Ephemeroptera within 1 to 4 weeks, Trichoptera 1 to 7 weeks, Plecoptera 4 to 5 weeks, and Simuliidae in 2 to 10 weeks. Populations of larvae smaller than 1 mm long were generally restored more rapidly. Procedures for an annual abatement programme for S. arcticum in the Saskatchewan River are outlined.

Impact of the flower- and shoot-tip-feeding beetle, Brachypterolus pulicarius (L.), on growth, flowering, and seed production of common toadflax, Linaria vulgaris (L.) Mill., was investigated using potted plants. Brachypterolus pulicarius had no effect on root or shoot biomass of attacked plants. Adult feeding by B. pulicarius delayed onset of flowering by 27 days relative to controls. Flowering of attacked plants was suppressed from mid-June until mid-July, but by mid-August flowering was similar to that of control plants. Total seed weight, individual seed weight, and percentage germination were all reduced significantly on attacked plants, resulting in a 74% reduction in number of viable seeds produced. Brachypterolus pulicarius is univoltine in Alberta, overwintering mainly as pupae.

The aquatic firefly Luciola substriata Gorham, 1880 (Coleoptera: Lampyridae) was first discovered in mainland China in 2000. The larvae of L. substriata inhabit ponds and lakes rich in aquatic vegetation. We recorded L. substriata feeding on two species of aquatic snails, Lymnaea stagnalis (L., 1758) (Basommatophora: Lymnaeidae) and Gyraulus convexiusculus (Hutton, 1849) (Basommatophora: Planorbidae). Three predators of fireflies were also recorded for the first time: the red swamp crayfish, Procambarus clarkii (Girard, 1852) (Decapoda: Cambaridae), the crab Eriocheir sinensis H. Milne-Edwards, 1853 (Decapoda: Varunidae), and the grass carp, Ctenopharyngodon idellus (Valenciennes in Cuvier et Valenciennes, 1844) (Cypriniformes: Cyprinidae). Egg incubation averaged 11 days at an ambient temperature of 20–25 °C. The prepupal stage of L. substriata lasted 6.2 days, and the pupal stage lasted 4.4 days. The imaginal period lasted from May to September. Courtship light-flashing activity peaked 1 h after sunset. The light spectrum of responsiveness of L. substriata was 425–603 nm, with a peak responsive emission at 504 nm. In addition, we have described and illustrated the morphology of L. substriata.

Two aspects of the biological control of R. buoliana are reported in this paper. From 1949 to 1957 rearing techniques were developed for and observations were made of the abundance and biology of parasites received in host material that was collected in Europe (Arthur). From 1955 to 1959 a critical evaluation of the parasites was made, largely based on a study at Elmira, Ontario, of the biology and habits of five representative parasitic species in the field and the laboratory to determine factors that limit their efficiency (Juillet).

Experiments conducted in a plantation of oil palms, Elaeis guineensis (Jacquin), infested with bagworms, Metisa plana (Walker), tested the hypotheses that crowding enhances the incidence of larval ballooning and negatively affects the size attained by pupae. Proportions of ballooning larvae increased with increasing densities of larvae per palm. The lengths of bags (and pupal cases) decreased with increasing numbers of bagworms per leaf. Ballooning of larvae from crowded palms is likely adaptive because individuals attaining large size at pupation have proportionately greatest survival, mating success, and fecundity.

The Nearctic species of the elaterid genus Athous east of the Rocky Mountains are revised. Of the 16 included species, two are described as new (neacanthus known from southern Quebec to northern Georgia and orvus known from Nova Scotia to Michigan to Virginia) and two species are transferred from Denticollis, namely, productus (Randall) and quadrosa Becker (as a new junior synonym of A. appalachius Van Dyke). Other new synonymies are: carolinus Van Dyke as a junior synonym of acanthus (Say), erebus Van Dyke of posticus (Melsheimer), and bipunctatus Provancher of productus (Randall). The European species campyloides is known from North America from near Quebec City and in the Canadian Maritime Provinces. Neotypes are designated for the five species described by Say and Randall and for one described by Melsheimer; lectotypes, when needed, are designated for LeConte’s, Melsheimer’s, and Candèze’s species. A key to the species is presented and the salient features and distribution maps for each species are included. Brief notes are given on three western species of Athous: two common species (rufiventris (Eschscholtz) and nigropilis Motschulsky) that are occasionally found east of the Rockies and orophilus Harold, which is known only by the type from the Bitter Root Mountains. Brief discussions are included of two European species, vittatus (Fabricius) and subfuscus (Müller), which have been intercepted at various eastern ports in Canada and the United States, but which have not become established in North America.

Flea beetle (Coleoptera: Chrysomelidae) species and numbers were determined from yellow sticky traps (n=11 180) set out in canola (Brassica Linnaeus, Brassicaceae) fields at 300 site years and 15 ecoregions across the Canadian Prairie provinces in each spring of 2007–2011 and in North Dakota, United States of America in 2010–2011. Peak numbers and relative species abundance varied with year, site, and ecoregion. Phyllotreta striolata (Fabricius) was most common in northern ecoregions, whereas Phyllotreta cruciferae (Goeze) dominated nearer the 49th parallel. The proportion of P. striolata in northern areas increased dramatically compared with surveys in the 1970s. Phyllotreta striolata displaced Psylliodes punctulata Melsheimer as the most common flea beetle in the Peace River Lowlands, displaced P. cruciferae as the most common flea beetle in the Aspen Parkland of central Alberta, Canada, and increased in proportion in central Saskatchewan and much of Manitoba, Canada. Once rare in southern ecoregions, P. striolata was found there in increasing numbers. Temperature was the most consistent weather parameter to predict occurrence of both P. cruciferae and P. striolata. Although P. striolata became more numerous over years in four of seven principal ecoregions, P. cruciferae remained the predominant species on traps with the highest numbers of flea beetles.

The Carabidae (Coleoptera) are a diverse family of beetles with almost 300 species identified in Nova Scotia, Canada. Carabid beetle communities have been studied in several agricultural systems, but not wild blueberries, an important crop in eastern Canada. In the interest of potentially developing conservation biological control programs in wild blueberry, we collected Carabidae in crop (fruit-bearing) and sprout (vegetative) blueberry fields in Nova Scotia in order to assess species diversity and abundance over space and time. Over 3200 specimens were collected, representing 51 species. A large portion of collected specimens (39%) were nonnative, and the most abundant species were generally predacious and synanthropic. Species diversity tended to be higher near forest edges than further into fields, but not for all abundant species. Several of the most prominent predators showed significant differences in preference of crop versus sprout fields, distribution throughout fields, and seasonable abundance. These findings have implications for conservation biological control efforts with carabid beetles against several insect pests in wild blueberry.

On three occasions in late August 1985, during the course of a study of the arthropod community associated with collards (Brassica oleracea var. acephala) (Cruciferae) in central New York State, two species of predaceous Heteroptera, the spined soldier bug, Podisus maculiventris (Say), and Nabicula americolimbata (Carayon), were observed feeding on adult flea beetles of the genus Phyllotreta. Evidence for predation on adult flea beetles is rare. Tahvanainen and Root (1972) and Kareiva (1985) reported practically no predation on adult Phyllotreta cruciferae (Goeze) in central New York, but scattered observations in Canada have documented occasional attacks on adult crucifer-infesting flea beetles by various insect predators (Gerber and Osgood 1975; Burgess 1977, 1980, 1982). This is the first record of predation on adult flea beetles by P. muculiventris and N. americolimbata. Burgess (1982) noted predation on adult P. cruciferae by another nabid, Nabis alternatus Parshley.

Feeding damage by the crucifer flea beetle, Phyllotreta cruciferae (Goeze), was assessed on 51 accessions of false flax, Camelina sativa L., and compared with damage to seven other crucifer species. Three experiments were conducted on seedlings in laboratory arenas infested with field-collected beetles. Feeding damage was estimated visually at daily intervals for up to 7 days. Natural infestation of false flax and other crucifers was observed in the field. Flea beetles fed little (0–10% consumption) on cotyledons or true leaves of any of the false flax accessions, and fed more (59–100% consumption) on the other crucifers. Flea beetles were observed sitting on false flax in the field, sometimes in high numbers, but they did not feed. In the laboratory, beetles eventually fed on cotyledons and leaves and once feeding was initiated, it tended to continue. Resistance in false flax may result from the absence of cues that initiate feeding, rather than a feeding deterrent. The high level of resistance in false flax would likely be economically beneficial if this species is developed as an oilseed crop. False flax could also be useful experimentally for identifying the cues that attract flea beetles to plants and stimulate their feeding.

Bacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.

The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.

The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.

Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.

The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.

Random counts of the white grubs, Phyllophaga fusca Froelich and P. anxia LeConte, in a permanent meadow did not conform to the Poisson distribution, there being an excess of uninfested and highly infested sample units over the expected number. But when the negative binomial series was fitted to the observed distribution, the discrepancies were not significant when tested by chi-square. Using a common k, the distribution of the various stages may be described by expansion of (q-p)−k, when values of k are as follows: egg 0.15, first instar 0.41, second instar 1.30, third instar 2.00, pupa 1.62, teneral adult 1.30. Aggregation resulted from the clumping of eggs at oviposition, and randomness increased with dispersal of the larvae. For all stages, the variance was proportional to a fractional power of the mean. Three transformations are offered for stabilizing the variance of field counts.

We studied the effects of frost on the survival rate of European earwigs, Forficula auricularia L., during the underground phase of their cycle and determined the timing of oviposition, hatching, and death of the adults; we selected couples and inserted them into the ground to a depth of 150 cm in an open area and along the foundations of a heated suburban house in the Montréal area. Oviposition occurred in November and December, and eggs hatched between January and early June, after an average incubation period of 79–189 d depending on experimental conditions. In the open area all adults and eggs at ground surface died, killed by frost, whereas those in the soil along the house foundation did not die. Males died during the fall and early winter; their longevity was shorter than that of females, which survived until shortly after egg hatch. Females and eggs survived temperatures as low as − 3 and − 2 °C, respectively. For successful reproduction, females must keep their developing eggs at a temperature low enough to delay hatching until mid-April.

An attempt is made to re-evaluate the data on the origin of the ovipositor in insects and to explain its mode of development in living forms. Comparative developmental data from other groups of animals is cited to substantiate the claim that part of the insect ectodermal genitalia is appendicular rather than sternal in origin. It is suggested that the primary abdominal segmental appendages have provided a source of competent tissue which through subtle changes in selection, has evolved along many pathways, to form the gonocoxae, the pleuropodia, the pseudoplacenta and perhaps the prolegs in many different taxa.

It is shown, by aid of sections through the insect embryo and larval stages, that the primary embryonic segmental appendages on the abdomen, do not differentiate; there is no loss of tissue and it cannot be proven that such appendages have been lost in insect phylogeny. The fact that they are represented still in the modern embryo, indicates that they have been retained. To explain the observable developmental details, it is suggested that abdominal limb histogenesis is arrested or suppressed in normal development, but this limb tissue retains its competence to differentiate. Thus development may be initiated again at a later time in postembryonic life. In this manner, the original limb tissue is available for organ formation in the maturing insect.

The study has suggested that the appendages on the eighth and ninth segments of the abdomen initiate but do not complete their development in the polypod embryo. Possibly the potential limb tissue is arrested in development because it has not undergone some vital change as regards its capacity to respond (competence) to an inductor, perhaps the inductor is not available or perhaps it is not available in the correct form.

There is evidence to suggest that the developmental capacity of the limb anlagen are reduced with time, so that full limb formation is not possible in postembryonic life: this can explain the development of abdominal coxae in the Thysanura and hence gonocoxae in higher insects. It is noted that should Gustafson's suggestion that the eversible sacs and gonapophyses are homologous with primary segmental genitalic ampullae prove acceptable, then the female ectodermal genitalia in insects would appear to have a dual origin.

It is emphasized that the speculation expressed are being subjected to experimental study in an attempt to verify the suggested ontogeny and phylogeny.

Sex attractants were demonstrated in extracts of virgin females from four species, representing three genera, of elaterids. Each attractant was species specific. An olfactometer is described that permitted paper chromatograms of the extracts to be bio-assayed for pheromone activity. RF values of the attractants from the four species are compared.