We present calculations of droplet sizes and product potencies that are theoretically required to deliver a lethal dose of Bacillus thuringiensis in one droplet to larvae of the eastern spruce budworm in aerial spray applications. The calculations are based on estimates of the dose required for 50% and 95% mortality [4.3 and 26.9 International Units (IU), respectively] and of the lowest dose that caused discernable feeding inhibition (0.5 IU) in force-feeding assays with sixth-instar larvae. For products containing 12.7–16.9 billion IU (BIU) per litre, the most widely used potency range, a 150- to 160-μm droplet is needed to deliver an LD95 and an 80- to 90-μm droplet to deliver an LD50, whereas droplets down to 40 μm are expected to cause extensive feeding inhibition. Our calculations suggest that current application prescriptions result in the delivery of a marginally effective dose to the target foliage and that budworm larvae have to ingest multiple droplets to obtain a lethal dose, a process that is thought to contribute to inconsistent spray efficacy. We predict that dose acquisition can be maximized by increasing product potency to 95 BIU/L, which would enable larvae to acquire a lethal dose by ingestion of only one or two droplets in the size range that is most commonly encountered on coniferous foliage (≤ 80 µm) after aerial application.

Studies on the population dynamics of the cabbage maggot, Hylemya brassicae (Bouché), on cabbage were carried out at two locations in Ontario from 1967 to 1970. Analysis of life-table data for nine generations showed that extensive mortalities occurred during the following age intervals: (1) egg stage; (2) between hatching and the second moult; (3) third-instar larvae; (4) pupal stage. Density dependent mortality occurred only during the latter period. The analysis of age interval survivals and graphical key factor analysis showed that "misadventure" of the larvae between hatching and the second moult was the key factor. The overall mortality process from egg to adult eclosion was density dependent, revealing the importance of pupal parasitism as a stabilizing factor. A predictive model based on density relationships was found to explain 62% of the variance in generation survival. The remainder of the variance is unexplained and may be due to sampling error and/or the influence of factors not measured.

Because microbial insecticides based on Bacillus thuringiensis subsp. kurstaki cause temporary cessation of larval feeding at sublethal doses, we hypothesized that the delivery of a given dose in a single droplet is more efficacious than delivery of the same dose in multiple smaller droplets. We tested this hypothesis by exposing larvae of the spruce budworm, Choristoneura fumiferana (Clem.), to an LD50 of a commercial product (Dipel 8L) in combinations of droplet sizes and densities that are commonly observed on coniferous foliage after aerial application. A nominal dose of 5.2 International Units (IU) was presented to fifth-instar larvae on one, two, or four balsam fir, Abies balsamea L., needles in the form of one, two, or four droplets with diameters of 84, 66, or 52 μm, respectively. The combinations of droplet size and density were chosen to represent an increasing degree of dose dispersion. Overall mortality after a 24-h exposure was significantly reduced with increasing dose dispersion from an average of 66% when the dose was presented in one 84-μm droplet on one needle to 40% when presented in multiple droplets on several needles. Increased dose dispersion reduced the proportion of larvae that were able to ingest the full dose, presumably because of feeding inhibition caused by ingestion of sublethal droplets. In addition, mortality of fully dosed larvae declined significantly with increasing dispersion, implying a reduction in the effectiveness of the ingested dose. When compared with operational spray deposits, our results suggest that efficacy of spruce budworm sprays may be improved by increasing the proportion of needles receiving a lethal spray deposit by increasing product potency and possibly the active ingredient application rate.

Pigmentation of heads and prothoracic shields of last-instar larvae, colour of pupae, and frequencies of haemolymph colour morphs in fresh pupae are used to support the taxonomic differentiation of the following members of the genus Choristoneura: fumiferana, biennis, orae, occidentalis, viridis, subretiniana, pinus pinus, p. maritima, and lambertiana. These characters are statistical in nature and not competent to relate a single individual unequivocally to a taxonomic group; nevertheless, a key is developed to assist identification of populations on the basis of the characters described. Interspecific relationships within the genus are considered.

The fore wing bases of Monotrysia can be homologized with the plan for a generalized insect wing base (Snodgrass, 1935). The wing bases of advanced Lepidoptera are very different from those of primitive forms. An evolutionary series can be traced through the order showing how the changes may have taken place.

The positions of the bending cuticle areas vary very little within the order. Within each superfamily the axillary region is surprisingly constant. It is impossible to distinguish between the wing bases of many related ditrysian families.

The jugum is particularly interesting; it is present in all the members of the old group “Microlepidoptera” and not only in the Monotrysia or “Jugatae”.

The first objective in the breeding of insects for physiological research is a sufficient number of insects of the greatest uniformity both within and between generations. The methods used must emphasize conditions of cleanliness and should preferably give freedom from offensive odours. Wit11 the growth of Knowledge of the factors involved and with the development of new food materids the rearing procedures have been modified. This article describes the present status of our methods used in the rearing of houseflies and roaches.

This paper introduces new names and synonymies to North American workers and corrects a few errors in the literature involving North American species of Scolytidae. A few distributional records are included to support some of the proposed synonymies. For convenience of reference the names of the species involved are arranged alphabetically.

Parasitoids of the trivoltine spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.), were studied in Connecticut apple orchards to determine their relative importance, emergence patterns, and seasonal abundance. Sixteen parasitoid species, including 12 eulophids, emerged from mines formed by 4th- and 5th-instar leafminer larvae. The species were primary, secondary, or facultative secondary parasitoids. Five were new records. The braconid Pholetesor ornigis (Weed) was the most abundant in the first and third leafminer generations, and the eulophid Sympiesis marylandensis Girault was the most abundant in the second generation. Ratios of parasitoids to Phyllonorycter spp. were generally higher in samples from unsprayed trees than in those from sprayed trees. Major parasitoids usually emerged 1 to 4 wk before their larval hosts became plentiful. Sweep samples indicated relatively high abundance of one or both major parasitoids during the first and second leafminer generations. Monitoring of parasitoids and the judicious use of insecticides may have a critical role in pest management programs utilizing native parasitoids of leafminers.

We consider the role of generalist Diptera in the pollination of two dioecious plant species, Clematis ligusticifolia Nutt. (Ranunculaceae) and Shepherdia canadensis (L.) Nutt. (Elaeagnaceae). In particular, we assess (i) whether or not generalist pollinators are unable to distinguish between the sexes of dioecious species and so visit the sexes at equivalent rates, and (ii) the number of flowers that generalist flies visit and revisit during a foraging bout, which would affect self-pollination if plants were hermaphroditic. We determined the visitation rate to each plant species during 10 min periods and recorded the number of flowers that individual pollinators visited and revisited per foraging bout. Diptera were the main pollinators, visiting both sexes at similar rates for both plant species. The main visitors to C. ligusticifolia were muscoid flies (small and large), Culicidae, and halictid bees. The number of flowers visited in this species varied with pollinator group, but groups did not differ in the frequency of revisits. Visitors to S. canadensis were primarily Syrphidae and Empididae. Neither the number of flowers visited nor the number of revisits differed between these two pollinator groups. The results for each plant species are discussed and contrasted, particularly with other studies of the behaviour of generalist and specialist pollinators. We compare the observed pollinator behaviours, and their implications for plant mating, with the various theories of the role of pollinators in the evolution of the dioecious breeding system in plants.

The susceptibility of the spruce budworm, Choristoneura fmiferana (Clemens), under laboratory conditions, to commercial preparations of Bacillus thuringiensis var. thuringiensis Berliner was reported by Angus et al. in 1961. This bacterium was recently tested, under field conditions, both as dusts and sprays. The results of ehese tests are presented here with comments on the effect of the environment and other factors.

Two new species, Tachinus beckeri from northwestern British Columbia and southern Yukon Territory and T. californicus from southern California, are described and their major diagnostic characters illustrated with line drawings and scanning electron photomicrographs. Tachinus jacuticus campbelli is placed in synonymy with T. jacuticus jacuticus and a new subspecies, T. jacuticus ullrichi, from Quebec and Labrador is named. Tachinus thruppi Hatch is removed from synonymy with T. frigidus and considered a valid species. Both T. thruppi and T. frigidus are redescribed and illustrated. A new, revised key to the species of Tachinus is included.New distributional data are presented for 40 species and new or revised distributional maps are presented for 24 species. Changes in classification of Tachinus proposed by Ullrich in his revision of the world species are reviewed and those that are accepted are incorporated into a revised classification of the North American species. These changes are included in a check list of the North and Central American species of the genus.

Six major subgroups of the Brachycera are recognized under the names Stratiomyomorpha, Vermileonomorpha new infraorder, Tabanomorpha, Nemestrinoidea, Pleroneura, and Eremoneura. Recent suggestions regarding the possible sister-group of the Brachycera are reviewed, and all found to be inadequately supported. Characters used to support possible relationships between the major subgroups (i.e. possible synapomorphies) are reviewed with respect to morphological interpretation and polarity. On the basis of this analysis, five partly conflicting possible groupings are discussed: (1) all other Brachycera as the sister-group of the Stratiomyomorpha; (2) Muscomorpha sensu Woodley (Nemestrinoidea + Heterodactyla); (3) inclusion of Nemestrinoidea in Tabanomorpha; (4) Heterodactyla sensu Lameere (Pleroneura + Eremoneura); and (5) an asilotabaniform group (Vermileonomorpha + Tabanomorpha + Nemestrinoidea + Pleroneura). Resolution of conflicts among these possible groupings will require critical morphological studies of the phallic complex and embryological studies of groups of Brachycera other than Cyclorrhapha. Because of present uncertainties, it is recommended that authors consider alternatives rather than rely on a single preferred concept of phytogeny at this time. Autapomorphies of the major subgroups are discussed in an appendix.

The posterior midgut of a seed-feeding pentatomid, Euschistus euschistoides (Vollenhoven), contains the proteinases cathepsin B and aminopeptidase. Cadiepsin B hydrolysis of benzoyl-DL-arginine-2-naphthylamide is activated by thiol chemicals and EDTA. Aminopeptidase hydrolysis of leucine-p-nitroanilide is activated by MgCl2 and inhibited by cysteine, glutathione, EDTA, and CaCl2. These results are similar to those obtained for cathepsin B and aminopeptidase from blood-feeding Hemiptera and support the hypothesis that catheptic proteinases are unique to this order.

In the laboratory, the mean number of eggs laid per female of the dark-sided cutworm, Euxoa messoria (Harris), fed on honey solution was 1303.8; when given water alone 261.3; and 86.4 when held without food or water. Adult food significantly increased the longevity and oviposition period and reduced the pre-oviposition period. There was no significant difference between the weight of male and female pupae. The weight of the female pupae was significantly correlated with: the oviposition period; the number of eggs laid; the longevity, except moths fed on honey solution; but not the pre-oviposition period, regardless of food taken as adults. Females fed on honey solution mated successfully, 30% of them more than once. When given water or nothing the number of mated females was reduced. Dissections showed that adult food accelerated the development of eggs and increased the fecundity potential.

A comparison of four sex determination methods shows that microscopic observation of the elytral declivity is the most accurate and rapid method for sexing large quantities of Douglas-fir beetles.

Thirty-five species of Latridiidae are reported in Atlantic Canada as a whole, 17 in New Brunswick, 14 in Newfoundland, 31 in Nova Scotia, and 14 on Prince Edward Island. Fifty-six new provincial records are reported (11 in New Brunswick, 9 in Newfoundland, 23 in Nova Scotia, 13 in Prince Edward Island). Twenty-two species are newly recorded for Atlantic Canada. Of these, Cartodere (Aridius) bifasciata (Reitter), Enicmus histrio Joy and Tomlin, Latridius consimilis (Mannerheim), Corticaria elongata (Gyllenhal), C. impressa (Olivier), C. saginata Mannerheim, Corticarina longipennis (LeConte), Melanophthalma helvola Motschulsky, and M. inermis Motschulsky are newly recorded in Canada, and C. bifasciata, E. histrio, and C. saginata are newly recorded in North America. Dienerella filiformis (Gyllenhal) is removed from the New Brunswick and Prince Edward Island lists. Corticaria dentigera LeConte is removed from the Labrador and Atlantic Provinces lists. Melanophthalma inculta Motschulsky syn. nov. and M. signata Belon syn. nov. are designated as a junior synonyms of M. inermis Motschulsky and M. picta (LeConte), respectively. Melanophthalma helvola Motschulsky is reinstated as a valid species. Lectotypes and paralectotypes of M. helvola and M. americana (Mannerheim) are designated. Approximately half of the species are adventive (16 Palaearctic, 1 Australian) and half are native (13 Nearctic, 3 Holarctic). Two species are of uncertain zoogeographic status. Although some species are synanthropic, several have colonized native habitats. Nova Scotia has the largest number of adventive species, probably as a result of trans-Atlantic shipping. New Brunswick has the fewest, at least in part because of insufficient collecting there. Early detection dates and introduction processes are discussed. The native faunas on Prince Edward Island, Cape Breton Island, and Newfoundland appear diminished (33%–40%) compared with those of the neighbouring mainland. Although all latridiids are mycetophagous, many in the region show clear habitat preferences; however, the ecological role of those species requires further investigation.

The larvae of jack pine budworm, Choristoneura pinus pinus Free., were reared individually on diet in the laboratory. Observation of ecdysis and measurement of the corresponding head capsules identified seven distinct instars. Parasitism by the common larval parasitoid Apanteles fumiferanae Vier. resulted in smaller head capsule size and retarded development during the fourth, fifth, and sixth instars of the jack pine bud worm.

Some of the results of an attempt to apply ecological principles in the solution of apple insect control problems in Nova Scotia have been given in previous papers by Pickett et al. (1946), Lord (1947, 1949), Pickett (1952), and MacPhee (1952). Briefly, these studies aim at an understanding of the changes in the interrelations of the species in an orcl-lard when spray materials are added to the environment. The emphasis to date has heen placed on the effects of spray chemicals on the populations of entomophagous species. The results of this work have already had a marked effect on orchard insect control practices in Nova Scotia.

In a survey of predaceous phytoseiid mites from 65 apple blocks in the Hood River Valley, Oregon, Metaseiulus occidentalis (Nesbitt) and Typhlodromus pyri Scheuten were the principal species present. Metaseiulus occidentalis predominated over T. pyri by a ratio of about 2:1 in 1984 mites collected during 1985. In experimental, commercial, and integrated pest management blocks, M. occidentalis was present alone or predominated over T. pyri in up to 88% of the blocks, whereas T. pyri occurred alone or predominated in up to 20% of the blocks. Both species occurred in near equal proportions in a maximum of 20% of blocks. An analysis of nine factors influencing the relative abundance of M. occidentalis and T. pyri indicated that vegetation in the habitat surrounding the block and the pesticides used were most important. In 1986, seasonal distributions and proportions of predatory mites found in individual blocks were similar to those found in 1985. The feasibility of managing mixed populations of T. pyri and M. occidentalis in Hood River orchards is discussed.

Adelges cooleyi (Gill.) causes galls on spruce in the forests and on shelter-belt and shade-tree plantings in Alberta. The alternate host is Douglas fir, on which the injury is less conspicuous. The tree species affected are white spruce, Picea glauca (Moench) Voss, Engelmann spruce, P. engelmanni Parry, and blue Douglas fir, Pseudotsuga menziesii (Mirb.) Franco. A. cooleyi is indigenous to North America.