The salivary glands of female Culex pipiens L each consist of three lobes divisible into five regions. Fine structure indicates that two regions may be involved in solute-linked water transport and three regions may have a glandular function. The fine structure is similar to that reported for Anopheles stephensi and Aedes aegypti. In C. pipiens, an axon of presumed neurosecretory function was found associated with the neck region of the medial lobe.

Complete development of the salivary glands occurs between the first and fifth days of adulthood. Morphological changes associated with blood-feeding were limited to the presence or absence of the salivary secretions in the apical cavities and duct lumen. During blood-feeding the contents of two of the glandular regions are voided, being replenished within 24 h Results are related to previous histochemical studies of the salivary glands of mosquitoes.

Estimates of global species richness for insects are based upon extrapolations from “known” to unknown faunas and hence rely upon accurate counts of species for the referrent taxon or region. The number of reference species depends upon the species concepts employed by workers in that group combined with the degree to which nonstandard (i.e. nonmorphological) approaches have been used. Genetic data are more directly applicable to the detection of the apparent absence of gene flow, which lies at the heart of any species concept, than is morphological information. But what criteria can be used as a practical guide to suggest the absence of gene flow and define species-level units? Minimally, the phylogenetic species concept requires that there be one fixed difference between two samples for them both to be considered discrete species. The assumptions accompanying this definition include the survey of sufficient geographic locations, loci, and individuals. Based upon six studies of mostly widespread, readily identifiable and well-investigated bee “species”, we estimate that the number of species currently recognised may underestimate the true figure by half (although for at least two of the studies localities have been undersampled and more collections are needed). Even when examples for which there are fewer than five fixed differences between samples are removed from the data set, the number of recognised species increases by perhaps as much as 50% (the same caveat regarding undersampling of populations still applies). We suggest that the presence of morphologically unrecognised species may be more common among widespread, easily identified “species” than is generally accepted. Whether or not similar levels of species underestimation apply to other faunas, such as tropical rainforest canopy beetles, remains to be investigated.

Populations of Neoseiulus fallacis (Garman) and Phytoseiulus persimilis Athias-Henriot, predators of Tetranychus urticae Koch, were reared under homogeneous environmental conditions by inbreeding without introducing new germ plasm.Mites from 1-year-old inbred cultures had high mortality in all stadia and generally lower viability. Oviposition was reduced and a high percentage of eggs failed to hatch. Further inbreeding resulted in the production of only sterile female mites. These data cast serious doubt on the possibility of genetically improving populations of predaceous mites with only limited germ plasm resources.

Phenology of fall dispersal into apple orchards is described for winterform pear psylla, Cacopsylla pyricola Foerster, in orchards located in Yakima and Wenatchee, Washington. Psylla in both regions first appeared on pear in mid to late September, reaching peak densities in late October or early to mid November, and then decreased in numbers to a low in December. Movement onto apple began in October; peak counts on apple occurred in late November to early December. There was considerable variation among years in phenology of leaf fall in pear and numbers of psylla entering apple. Leaf fall in pear was delayed in a cool, wet fall (1991) compared with warmer and drier years (1990 and 1992), and temperatures during leaf fall were consequently lower in 1991. Numbers of psylla moving onto apple were considerably lower in 1991 than 1990 or 1992. Catch on sticky traps and dispersal rates onto apple were both positively correlated with rates of leaf fall in pear, temperature, and density of psylla on pear.

In laboratory studies, an aqueous suspension of a commercial wettable powder formulation of Bacillus thuringiensis var. kurstaki (strain HD-1) containing at least 25 billion viable spores/g and 16000 International Units of Potency (Trichoplusia ni (Hübner))/mg prevented infestations of Indian meal moths, Plodia interpunctella (Hübner), and almond moths, Cadra cautella (Walker), in corn and wheat at a dose of ca. 120 mg of formulation/kg of grain. Treatment of a 100-mm-deep surface layer was more effective than treatments 33 or 67 mm deep and as effective as treatment of the entire grain mass Lack of uniformity in applying B. thuringiensis to the grain kernels caused a small decrease in effectiveness. Dust and bait formulations at about the same doses were as effective as the suspension, but the bait was undesirable because it supported the development of beetle larvae. The formulation was less effective in controlling the Angoumois grain moth, Sitotroga cerealella (Olivier): doses that gave complete control of the Indian meal moth and the almond moth reduced emergence of adult Angoumois grain moths by only about one-third.

The species of Pteromalidae (Chalcidoidea) introduced to British Columbia, Canada, from Europe in 1949 as Trichomalus fasciatus (Thomson, 1878), Xenocrepis pura Mayr, 1904, and Habrocytus sp. for classical biological control of Ceutorhynchus obstrictus (Marsham, 1802) (Coleoptera: Curculionidae) are shown to be misidentifications of Trichomalus perfectus (Walker, 1835), Mesopolobus morys (Walker, 1848), and Stenomalina gracilis (Walker, 1834), respectively. Species reared subsequently from seedpods of Brassica spp. (Brassicaceae) in British Columbia and reported in the literature under the first three names are shown to be misidentifications of, respectively, Trichomalus lucidus (Walker, 1835), Mesopolobus moryoides Gibson, 2005, and one or both of Pteromalus puparum (L., 1758) and T. lucidus. There is no evidence that either T. perfectus or M. morys established in North America, but S. gracilis is newly recorded from southern British Columbia based on specimens reared from Brassicaceae seedpods in 2004 and 2005.

Improvements in the rearing methods for axenic mountain pine beetles were made by standardizing the nutritional and physical composition of a yeast-fortified ground phloem diet. By eliminating handling and possible malnutrition of neonate larvae, and by use of individual rearing units to reduce hazards associated with microbial contamination, one person produced batches of 400–500 axenic beetles. Beetles produced by this method were morphologically and anatomically equivalent to and more fecund than field beetles, were significantly smaller than their parental stocks, and perhaps required more degree hours above 40 °C in developing from egg to adult.

A sensillum in the shape of a truncate cylindrical peg is present on the apex of the antenna in both sexes of Itoplectis conquisitor (Say). The sensilla occur in distinct fields of 19 to 38 pegs per antenna in males , and 26 to 35 pegs per antenna in females (x = 30.6). The pegs measure 1 to 15 μ, in height in males and 4 to 13 μ in females, and 2 to 6 μ in diameter in males and 2 to 5 μ in females. Pegs in the inside ranks at the very tip of the antenna are shorter than those in outside ranks which are more subterminal in position. This height variation results in the flat to slightly concave tips of the pegs being aligned on approximately the same plane. Innervation was confirmed by light microscope observations of sectioned material. The placement of the pegs at the antennal apex suggests that they perceive stimuli in the act of antennal tapping.

A wide range in feeding damage as defined by leaf scars among 27 cultivars of florist’s chrysanthemum was apparent for the western flower thrips, Frankliniella occidentalis (Pergande). Assessments based on numbers of feeding scars or ranking of cultivars on the basis of the leaf area damaged by feeding were in close agreement. Cultivars with the most feeding damage under growth room conditions, such as cvs. White Marble and Polaris, were the same as those in plots within a naturally infested commercial greenhouse. Under growth room conditions, a 2- to 4-week exposure of plants to a population of thrips was sufficient to evaluate feeding damage. Closely related cultivars had similar levels of feeding damage, and foliage of yellow-flowered cultivars was significantly more attractive to thrips for feeding than foliage of white-flowered sister cultivars during the pre-bloom period. There was a low correlation between feeding damage and incidence of the tomato spotted wilt virus among cultivars in both growth room and greenhouse tests, indicating that virus susceptibility of cultivars was epidemiologically more significant than the feeding activity of western flower thrips.

The eye-spotted bud moth, Spilonota ocellana (D. & S.), has been and continues to be an orchard pest of considerable economic importance in the temperate zone of North America. During the past seven years, observations have been made on the ecology of this insect in Nova Scotia. Among the biotic agents found attacking it is the hymenopterous parasite Agathis laticinctus (Cress.) [Microdus ocellanae Richardson].

The number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

Over a century ago Peck (4) observed that open-growing stands of white pine, Pinus strobus L., were subjected to greater weevil damage than were those growing in mixture with, and shaded by, other tree species. This observation, which was later corroborated by Graham (2) and MacAloney (3), suggested possibilities of silvicultural control of the insect by means of plantation growing of white pine in various kinds of mixtures. The results of this work were recently assessed in a review paper by Belyea and Sullivan (1), who concluded that further silvicultural control measures be curtailed until the physical and biological requirements of the insect were defined in terms of measurable factors of the environment. Investigations were carried out (6, 7) to establish the conditions of temperature, light, and moisture favourable for feeding, copulation, and oviposition of the adults, and development of the larvae. The results indicated that P. strobi is well adjusted to the environmental conditions in open stands of white pine, but that the limitations imposed by weather on weevil oviposition might be a major factor contributing to the inability of the insect. to adapt readily to the climate of many shaded stands. The present paper is an attempt to assess the role of weather and the physical characteristics of white pine leaders, hereafter called leaders, in limiting the successful invasion, by the weevil, of white pine stands growing as partially suppressed, understory trees. Emphasis is placed on providing an understanding of the differences in the climate of weevil habitats, adult feeding and oviposition behaviour, and survival of weevil populations in exposed and shaded stands of white pine. In addition, records were obtained for the purpose of forecasting differences in both the timing and amount of such acts as oviposition and feeding in populations in the two habitats.

Wishart (in press) reported on surveys of parasites of the species of Hylemya that attack cruciferous rops in Canada. A similar survey was carried out in Europe during 1949 to 1954 to determine whether there were parasites not already present in Canada that, if introduced and established, might aid in the concml. Some data gathered in this survey were published previously (Wilkes and Wishart, 1953; Wishart and Monteith, 1954).

The intensive use of sex pheromone traps in an insecticide-free apple orchard from 1972 to 1974 reduced the codling moth population and level of fruit damage. The sex ratio of bait-trapped adults indicated that the male population was being reduced by the pheromone traps. In commercial orchards pheromone trapping of males suppressed codling moth damage to fruit but the amount of damage was above acceptable economic levels.

The flea beetle Altica carduorum Guer. was released in four provinces in Canada to aid in the control of Cirsium arvense (L.) Scop, but did not survive in open fields with the exception of a small colony at Lacombe, Alta. It thrived, however, at four locations in different climates when protected by field cages. The mortality of the eggs and(or) the larvae reached 91%, that of the overwintering adults 83%. The mortality of the immature stages was apparently mainly due to predation and at a release site near Belleville Leptus sp. near curtipes Schweizer and Sphaerolophus sp. (Erythraeidae: Acarina) were implicated in tests with A. carduorum eggs labelled with P32. Field and laboratory experiments showed that dry continental summers, such as occur at Summerland, B.C., and Lacombe, Alta., were probably not detrimental to either egg development or pupation.

The effect of daily day-degrees C in relation to brood age was investigated to determine its influence on the induction of larval (prepupal) diapause in Dendroctonus rufipennis (Kirby). Daily day-degrees of less than about 9° above the development threshold (6.1°C) induced diapause in most of the broods while diapause was averted by daily day-degrees C of 10 or more above the threshold. Induction of diapause occurred no later than third larval instar; temperature changes during the fourth instar produced no change in aversion or induction of diapause. Laboratory results reveal that field temperatures during larval development determine whether most beetles have a 1- or 2-year life cycle.

The larvae of 17 species of Hydroporus Clairville were described and characterized; a key for their discrimination and illustrations of structural features of first- and third-instar larvae are provided. Many structural features, especially those of chaetotaxy and porotaxy of head capsule, head appendages, legs, last abdominal segment, and urogomphi, were found to be useful for taxonomic and phylogenetic comparisons. Based on 21 larval characters, the phylogenetic relationships among the five main lineages of Hydroporus (s. lat.) occurring in North America were studied. Structurally, the species of the subgenus Hydroporus (s. str.) and of the vilis species-group (H. planiusculus Fall) were found to be the most generalized taxa whereas the subgenera Neoporus Guignot and Heterosternuta Strand encompassed the species with the most derived condition. The subgenus Heterosternuta was closely related to the subgenus Neoporus and both subgenera were hypothesized to form a distinct monophyletic unit on the basis of five synapomorphies. The only representative of the oblitus species-group studied, H. paugus Fall, was related to Hydroporus (s. str.) and the vilis species-group by the shape of the siphon. This species was a very peculiar clement within Hydroporus (s. lat.) because it was the only known species of the genus without stemmaia in the first- and second-instar larvae, with stemmata greatly reduced in size in the third-instar larvae, and with a secondary dorsomedian seta on antennomere 2. The larval features of Hydroporus (s. lat.) were compared with those of Hygrotus Stephens. The comparison suggested that both genera form a monophyletic unit, that each of them is a distinct monophyletic unit, and that Hydroporus (s. lat.) is the sister-group of Hygrotus Stephens.

The tribe Thoronini Kozlov, 1970 as interpreted here in its broader sense includes also the tribes Pseudanteridini and Tiphodytini as proposed by Kozlov (1970), i.e. the following genera: Thoron Haliday, 1833, Neothoron n. gen., Pseudanteris Fouts, 1927, Thoronella n. gen., Microthoron n. gen., Tanaodytes n. gen., and Tiphodytes Bradley, 1902. The new taxa described are: Neothoron lautus n. gen. and n. sp., Ecuador; Thoronella elegans n. gen. and n. sp., Brazil; Microthoron baeoides n. gen. and n. sp., Malaya; Tanaodytes longipes n. gen. and n. sp., Malaya; Tanaodytes soror n. sp., Ceylon; Tiphodytes godavari n. sp., Nepal; Tiphodytes mymar n. sp., Malaya; Tiphodytes selangor n. sp., Malaya.The genera Thoron, Pseudanteris, and Tiphodytes are recorded for the first time in Canada. The name Calliscelio Ashmead, 1893 is considered a synonym of Calotelea Westwood, 1837 (new synonymy).The species of Thoronini, the biology of which is known, parasitize eggs of water Heteroptera (Gerridae, Nepidae) and it is assumed that most if not all species of this tribe either live in, or are closely associated with, aquatic or semi-aquatic habitats. This is inferred, in the case of species for which definite information is lacking, from the sites in which the adults have been collected, all of which were near water.

It has been shown that Drosophila melanogaster fly to the source of an attractive scent by making a series of highly stereotyped responses to olfactory and visual stimuli (Kellogg, Frizel, and Wright, 1962). The comparable processes by which Aedes aegypti are guided to a warm-blooded host have now been studied and are the subject of this paper.

Larval growth and pupal parameters of the forest tent caterpillar (Malacosoma disstria Hübner) reared on the foliage of two host trees (Populus tremuloides Michx. and Acer saccharum Marsh.) and one nonhost tree (Acer rubrum L.) were quantified. This was achieved by undertaking a larval development bioassay under controlled laboratory conditions, but using fresh leaves collected in two field seasons. Larvae fed foliage of P. tremuloides grew exponentially and began to pupate after 3 weeks. Larvae fed with A. saccharum gained significantly less weight and had a reduced number of larvae pupate, and the pupae weighed significantly less than their counterparts fed on P. tremuloides. All larvae that were fed the foliage of A. rubrum died within 2 weeks. A nutritional utilization bioassay with fourth-instar larvae revealed that the foliage of A. saccharum has a growth-inhibitory component, whereas that of A. rubrum is antifeedant. Reasons are discussed for the discrepancy between the many reports of A. saccharum being a food host for M. disstria in the field and the laboratory results.