Despite their inert appearance, the wings of insects are living appendages and are supplied with blood. This is true for definitive wings as well as for developing ones, and for modified wings such as tegmina, elytra, hemelytra, and halteres as for those that are specialized for flight. Typically the blood circulates only through the wing veins, but in some insects it escapes into the surrounding membrane in certain areas, and in highly modified forms it may be entirely unconfined. The course of circulation is basically the same in the wings of most insects. It flows outward from the body in the costo-medial veins, moves toward the posterior margins via cross-veins, and returns to the body through the cubito-anal veins and axillary cord. However, rhe precise route followed is highly variable concomitant with distinctive patterns of venation in different taxonomic groups and with wing structure. This is illustrated for a number of orders.

La diète se compose du sucrose, de 23 acides aminés et amides dont les proportions ont été établies à la suite de l'analyse de l'hémolymphe et du miellat du puceron, de dix vitamines du complexe B, d'acide ascorbique, de benzoate de cholestérol et d'un mélange de sels, le tout en solution dans l'eau.

Sur cette diéte, les pucerons du pois du biotype R1 se développent normalement, ont une croissance larvaire légèrement inférieure à celle des pucerons témoins maintenus sur des pois de la variété Perfection et presque tous atteignent l'état adulte sans mortalité.

Knowledge of the approximate rate of nymphal development at different altitudes should be most useful in planning control operations against the clearwinged grasshopper, Carmnula Pellucida( Scudder), on rangelands in the interior of British Columbia. When hatching and development are observed ar any one altitude varying from under 1500 ft. to over 3500 ft., it should he possible on the basis of tGs knowledge to predict the most advantageous time to commence control operations at other altitudes on the same rangeland. Economic damage can be controlled by a single treatment, applied before the nymphs have developed to the fourth instar.

This exhibit represents part of the work of the Department of Zoology in the past 5 years, and others who have contributed to it are F. Matsumura, Z. H. Abedi, T. Kimura, P. G. Fast, J. G. Towgood, J. N. Telford and N. H. Khan.

The work with the mosquito Aedes aegypti has involved study of 8 susceptible strains. The mechanism of DDT-resistance has been found to be associated with its detoxication by an enzymic process of dehydrochlorination to DDE; the amount of DDE produced has been found to be directly proportional to the resistance level, both by experiments with larvae in vivo and with larval homogenates incubated with DDT and glutathione in vitro. A secondary resistance mechanism in American strains has been a very pronounced secretion and excretion of peritrophic membrane by the larvae.

During intermolt in the fifth instar nymph the epidermal cells are compact, with many mitochondria which appear dense, lack well defined cristae, and are considered relatively inactive. The cell membranes are much folded and show plasmodesmata and microvilli at the juxtaposition of two cell membranes. The endoplasmic reticulum is well formed and well supplied with ribosomes; in the compacted cells the reticular membranes may assume bizarre shapes such as a ball of concentric rings. The nuclei are small with inconspicuous nucleoli.

This exhibit represents part of the work of the Department of Zoology in the last 15 years, and others who have contributed to it in the past are L. Burgess, D. G. Peterson, R. P. Thompson, W. L. Sippell and M. R. Smart.

The laboratory experiments have been made with Aedes aegypti in a large cage, in which a choice is offered between a pair of objects differing in one factor, or a pair of emission ports for airborne vapours. Thus six factors have been evaluated and their order of importance has been found to be as follows:

La tordeuse des bourgeons de l‘épinette, Choristoneura fumiferana (Clem.), fait partie intégrale du complex biologique des forêts de conifères de l'Amérique du Nord. Périodiquement elle multiplie d'une façon extraordinaire et entraîne la destruction généralisée du sapin et de l'épinette. La cause principale des invasions de cet insecte, c'est la présence sur de vastes territoires de peuplements contenant un fort pourcentage de sapins rendus à maturité. Notre pays a été le théâtre de deux invasions spectaculaires de cette tordeuse depuis le début du siècle, mais on savait fort peu de choses sur celles qui ont sévi auparavant. Nous avons cherché à obtenir des renseignements à ce sujet par l'examen des anneaux de croissance, car, comme l'on sait, toute perturbation dans la croissance d'un arbre au cours d'une même saison de végétation entraîne une réduction dans l'épaisseur des couches de bois. En conséquence, la comparaison de l'accroissement en épaisseur des anneaux ligneux sur de très vieux arbres appartenant à diverses essences rencontrées dans un même site, permet de dépister les années où l'insecte a exercé ses ravages.

The exhibit shows how knowledge of food relationships and distributional patterns has aided in the recognition of sibling species, i.e., of species that lack evident distinguishing characters, in three genera of Chrysomelidae. Both adults and larvae of all species exhibited feed on leaves. All can be reared in the laboratory on their normal fool-plants with little mortality.

This exhibit represents some portions of a study of the stomodaeal nervous system, neurosecretory cells, corpora allata, corpora cardiaca, and prothoracic gland cells in post-embryonic stages of Aedes aegypti (L.), the yellow fever mosquito. Some of these structures share the common property of being involved in the production of hormones.

Mosquitoes were reared under standard conditions. Larvae, pupae and adults were fixed at timed intervals in histological fixatives. Sectioned specimens were stained in Gomori's aldehyde-fuchsin, Gomori's chrome-haematoxyh-phloxin and other stains. The aldehyde-fuchsin technique, which imparted a bright purple colour to neurosecretory material, was particularly useful. Vita1 staining with methylene blue was used to trace the stomodaeal nervous system

The electron microscope can be used to advantage in the investigation of a physiological problem, where the reactions are differentiated at the cellular rather than at the tissue level. This set of electron micrographs shows some of the morphological arrangements accompanying various excretory functions in Tenebrio larvae.

The Tenebrio larva has a cryptonephridial arrangement of the Mlalpighian tubes, in that the distal end of each tube is applied to the surface of the rectum and covered by a heavy membrane, in which periodic “Windows”, the leptophragmata, occur where the membrane is very thin or replaced by a different structure. The free part of the tubes can be differentiated into physiological zones by means of their succinic dehydrogenase activity, which is high in places and low in others along the tube showing no gross morphological differences. The hindgut also contributes to the excretory work of the iinsect. Thc cryptonephridial part of the tube is unique in ultra-structure among cells so far studied. The membrane structure is very extensive, and mitochondria very numerous. Membrane structures bearing no resemblance to ordinary reticulum are common, especially near the leptophragma. The leptophragma is a complex structure, made up of parts from both the Malpighian tube cell and surrounding membrane. Its appearance strongly suggests that it forms a region of easy transport for water and solutes between lumen of tube and body cavity.

De 1956 à 1962, 151 lignées parthénogénétiques du puceron du pois, Acyrthosiphon pisum (Harr.), furent collectionnées dans les régions cultivées du Québec et de la partie de l'ontario située à l'est du lac Huron. On remarqua qu'en élevage sur pois Perfection, les lignées les plus fortes étaient celles provenant de la luzerne et les plus faibles, celles provenant du trèfle. D'autres lignées de comportement intermédiaire étaient originaires de l'une ou l'autre plante-hôte primaire. On a réussi à démontrer l'existence de races, c'est-à-dire de groupes de biotypes particulièrement abondants sur une plante-hôte, à la suite d'élevages standardisés aux conditions suivantes: quatre groupes de trois femelles vivipares aptères de chaque lignéte étaient élevés séparément, chacun sur six plants de pois Perfection, pour une période de neuf jours à la température constante de 68 degrés Fahrenheit.

The paper of Koenike (1895) on the North American water mite fauna (Abh. naturw. Ver. Brewmen 42: 167-266) and a subsequent revision (Koenike 1912, Trans. R. Canad. Inst. 9: 281-296) together listed thirty-seven species of Hydracarina. These reports were based on materials collected and transmitted to Dr. F. Koenike by the eminent Canadian geologist, Dr. J. B. Tyrrell. Seven of the thirty-seven species were reported from localities in the Rideau Lakes district and in the vicinity of Ottawa.

Female black flies may be sorted into two age groups, the nulliparous and the parous, by the changes in the ovary including the absence or presence of follicular relics. This highly accurate method, developed in Russia and England for Anopheles mosquitoes (Beklemishev 1944; Lewis 1958a), has been recently adapted for use with black flies (Lewis 1958b; Davies 1961).

A pictorial representation of the gut of the green peach aphid, Myzus persicae (Sulzer), is shown based on dissection, light microscopy, and electron microscopy.

The sucking pump is crescentic in cross section with a thick, rigid, posterior wall and a thinner, flexible, anterior wall. Dilator muscles arise on the clypeus and are inserted along the midline of the anterior wall of the pump chamber. Morphologicael evidence of the sucking action of the pump is included.

It has been suggested that information on the phylogenetic relationships of genera and species could be obtained by comparing the amino acid sequence in the homologous proteins of different species. This procedure is extremely difficult and time-consuming.

However, a relatively rapid characterization of proteins can be obtained by analysing their mobilities with starch-gel electrophoresis and examination of antigenic diversity by the agar gel diffusion technique of Ouchterlony.

Most of the animal species have developed specific feeding habits, and this applies especially to the larvae of leaf-mining Lepidoptera. The genus Nepticula comprises about 60 species of minute moths. In general, the forewing is purple to black with a transverse, golden or silvery band. Because of this similarity of pattern, it is often impossible to identify many of the species in the adult stage. The larvae mine within the tissues of leaves, usually just beneath the upper epidermis, consuming the palisade layer of cells. Each of the species feeds in a characteristic manner. For example, N. rosaefoliella Clem. forms a serpentine mine usually along the edge of a rose leaf, and N. juglandifoliella Clem. forms a linear mine along a vein. The mine of an undescribed species on elm starts as a semi-serpentine track and abruptly enlarges into a viscera-like blotch; that of another undescribed species on willow terminates in an irregular blotch; and so on. Each species engraves its own symbolic characters, and whoever has learned to read the symbols can readily determine the species that made them.

During the course of a study of the bionomics of the pitted ambrosia beetle, Corthylus punctatissimus Zimm., in southern Ontario in 1959, the method of overwintering fungal spores and their transmission from brood galleries to healthyplants by the beetle was determined. It was found that a structure exists, in the prothorax of males of C. punctatissimus, for this purpose. The spores are stored in a long, folded tube on each side adjacent to the prothoracic wall. The opening of each tube is in the prothoracic coxal cavity and is opened or closed by a process on the coxa. Since there are no muscles attached directly to the tubes, the spores are probably discharged by the squeezing action (on the tubes) of the retracted head against the prothoracic wall. The inside surface of the tubes is very smooth and glossy, producing a minimum of resistance to the flow of spores. No evidence was found of any comparable structure for storing spores in the females of C. punctatissimus.

In Canada eight species of ticks are implicated with ten and possibly seventeen diseases of man and animals. The most important of these, tick paralysis, is caused by Dermacentor andersoni Stiles, and of three hundred human cases in British Columbia since 1910, thirty have been fatal. In livestock, outbreaks have involved up to four hundred cattle in a single herd, with losses of up to fifty head. Other diseases resulting from tick toxins include a paralysis of cattle by Oyobius megnini Dugès, which has caused twelve deaths since 1955; occasional deaths in deer and moose from heavy infestations of Dermacentor albipictus (Packard); and slow-healing sores in man resulting from the bites of Ixodes pacificus Cooley and Kohls.

well over half the agricultural weeds in Canada are introduced species, many of them introduced without their chief insect enemies. Biological control, by the introdtiction of these insects, would reduce the aggressiveness of these weeds; but it should be regarded as a supplement to, and not a replacement for, mechanical or chemical control as it is most likely to succeed where these methods are ineffective or impractical. Thus the weeds chosen for biological control are either: resistant to chemical or mechanical control; serious pests of range or other low quality land where conventional methods of control are impractical; or resistant to control because they are continually spreading on to arable land from hedgerows and waste areas.