A detailed morphological study of the immature stages of Contarinia pseudotsugae Condr., C. constricta Condr. and C. cuniculator Condr., along with their description, is presented in this paper. This work is based on examinations of several hundred larvae of each species, with numerous observations of larvae in the act of moulting and pupating which confirmed the morphological indications of three larval instars. Included also is a brief description of the galls associated with each midge species. Terminology used in the larval descriptions follows that of Möhn 1955.

Cocoons of winter moth, Operophtera brumata (L.), reared from larvae collected in Europe, were imported to obtain insect parasites for release in Canada. Normally the sequence of handling the host cocoons consisted of: summer storage (July to October); autumn storage (October to December) during which host emergence occurred; winter storage (January to May); and, finally, a period of incubation (May to June) to obtain in time for release against the larval stage of the host.

Siphona irritans (L.), commonly known as the horn fly, is a serious pest of cattle. In southern Alberta, ten thousand flies have been counted on a single host animal. Properly conducted control studies require the establishment of a permanent laboratory colony. Previous attempts to establish such a colony had not been successful (McLintock and Depner, 1957) as more information about the biology of the fly was needed. The results presented in this paper will help provide this information.

Most of the relative humidity gradients used in ethological studies of insects are of the alternative type in which a choice between only two relative humidities is possible (Perttunen, 1953; Wigglesworth, 1941). Sometimes, during investigations of behaviour and distribution of insects, it may be desirable to know the humidity preferred when insects are exposed to an environment in which a number of different humidities prevail in a definite, specified range. In some cases both the range of humidities in a gradient and the values of the extreme humidities apparently affect the preference exhibited by certain arthropods (Perttunen, 1953; Bursell and Ewer, 1950; Lees, 1943). The circular apparatus described here allows the simultaneous production of two identical gradients, one in each half of the circle.

A low speed wind tunnel was needed for work by Dr. J. Juillet at the Belleville Institute to determine the number and direction of insect flights in a given time at different wind speeds and hence to determine the influence of wind on flight activity. This paper describes a tunnel designed to produce wind speeds of up to 9 miles per hour with uniformity within ± 5 per cent.

This is a report on a program to sample the European corn borer, Ostrinia nubilalis (Hbn.), with the object of obtaining reliable statistics for life tables (see e.g. Morris, 1955; LeRoux and Reimer, 1959).

Basic studies on factors determining abundance of the European corn borer are few, some of the most notable having been carried out by Barber (1926), Huber et al. (1928), Thompson and Parker (1928), Stirrett (1938), Vance (1943), Baker et al. (1949), Bigger and Petty (1953), Everett et al. (1958) and Chiang and Hodson (1959). None of these studies was a thorough study of mortality factors in development of the European corn borer from endemic to epidemic levels. A number of specific factors known to be important in the epidemiology of this species have been investigated by Arbuthnot (1949), Neiswander (1952), Goleman (1954), Chiang and Holdaway (1955), and Chiang (1959), and the application of biometric techniques to the sampling of corn borer populations has been studied by Beard (1943), McGuire (1954), and Bankcroft and Brindley (1956). None of the latter authors have, however, investigated sampling techniques relating to the development of life tables for this species.

Since Neodiprion swainei Midd. overwinters within cocoons in the soil, it is necessary for the population ecologist to sample the forest floor. One-footsquare units of soil have been used for sampling cocoons in population studies of N. swainei in the Province of Quebec. After removal from the forest floor the samples were placed individually in cotton bags for shipment to the laboratory. The ordinary method to extract cocoons required that the samples be first broken up by hand, then passed over various-sized screens to eliminate the sand and other small particles. Following this, each sample was carefully manipulated and scrutinized by one worker and the cocoons removed, then similarly re-examined by another worker. Best results were obtained when the samples were dry.

The American dog tick, Dermacentor variabilis (Say) is abundant in many localities throughout the coastal plains of eastern United States (Bequaert, 1946) and according to Lewis (1960) occurs in sparse numbers as far north as the Bangor area in Maine. In Canada, it is found from Saskatchewan to Nova Scotia (Gregson, 1956) but seemingly only in small numbers and in widely separated areas east of Manitoba. The published information on its occurrence in Nova Scotia is limited to a single record by Twinn (1944) who mentioned that male and female American dog ticks in “considerable numbers” were taken at the upper waters of the Sissiboo River in Digby County. Since its presence in western Nova Scotia in infestation numbers does not appear to be generally known outside that province, it is felt that a note on our observations on D. variabilis might be of interest.

Nearctic horse flies usually identified as Tabanus (Hybomitra) frontalis Walker or septentrionalis Loew, or simply as T. frontalis septentrionalis complex, have puzzled taxonomists for more than a century. These tabanids (Figs. 1-3), which are among the most widely distributed, most abundant and most troublesome biters of animals and man in North America, are extremely variable, especiallly in color and size. Those who have studied the group have widely different views concerning the taxonomic significance of the variations observed. To date, five nominal species (excluding T. opacus Coq.) have been described from small samples of populations of the group from various parts of Canada, i.e., frontalis and incisus Wlk. (Nova Scotia), septentrionalis Loew and labradorensis Enderlein (Labrador), and canadensis Curran (central Manitoba).

Prior to 1950 the European red mite, Panonychus ulmi Koch, was a major pest in Nova Scotia apple orchards, and brown mite, Bryobia arborea M. and A., was practically non-existent. Lord (1949), showed that the sulphur fungicides, commonly in use up to that time, were detrimental to some of the predacious species and toxic to the brown mite. After 1950 red mite populations became negligible and, although the brown mites increased, they did not become sufficiently abundant to cause economic damage. This shift of population balance in Nova kotia orchards has been attributed to the gradual replacement of sulphur and other detrimental materials by pesticides less harmful to predators of the mites (Pickett 1953).

An improved method of rearing the Douglas-fir beetle (Dendroctonus pseudotsugae Hopk.) was recently developed by using wax-coated slabs of Douglas-fir. To fully utilize this method, it was desirable to follow beetle development within the slabs without removing the bark. If this could be achieved it would oDen the door to manv advances in research. Several radiological techniques $ere considered and the x-ray appeared well adapted. The slabs were small enough to be moved to the x-ray machine and to fit on standardsize x-ray film. Also, x-ray units are readily available in hospitals and medical centres. Accordingly, tests were made of x-ray techniques for detecting Douglas-fir beetles in infested slabs of Douglas-fir.

The cinnabar moth, Hypocrita jacobaeae (L.), is the principal enemy of tansy ragwort, Senecio jacobaea L., in Europe. To determine if this moth could be safely liberated in Canada to control tansy ragwort, breeding stocks were imported as pupae from Sweden and Ireland for laboratory feeding tests. Larval feeding tests with various important economic plants before the moth was introduced to New Zealand from Britain (Cameron, 1935), to Australia from Britain (Currie and Fyfe, 1938), and to the United States from France (Parker, 1960) showed that the larvae would not survive on any of those tested. Such investigations specifically excluded certain crops from damage by the moth but did not indicate the range of plants that can be eaten. It is essential that an insect used in weed control should be highly restricted in its diet. If this restriction is related to nutrient discrimination, as described by Kennedy and Booth (1951) for Aphis fabae Scop., it would be necessary to screen many more economic plants than if it is related to “secondary” plant substances associated with a taxonomic group, as described by Fraenkel (1953). Thus, besides ad hoc tests on important plants, tests to determine the potential host spectrum of an insect are warranted before it is liberated against a weed. The plant spectrum of the cinnabar moth was determined by feeding the larvae on several genera in the tribe Senecioneae and representatives of most other tribes of Compositae that occur in Canada.

Two publications dealing with the seasonal development of species of Conophthorus have appeared in recent years. Lyons (1956) reported on a study of C. resinosae Hopk. in red pine, Pinus resinosa Ait., in Ontario, whereas Ruckes (1958) gave the details of his observations on C. radiatae Hopk. in Monterey pine, Pinus radiata D. Don, in California. Both species attack the developing cones of the host tree, although Lyons found that C. resinosae would develop in the shoots of red pine, and occasionally attacked the second-year cones of jack pine as well. The jack pine-inhabiting species, however, has been found almost exclusively in the shoots; only seven second-year cones that had been mined were collectcd during two years of investigation.

Reports in the literature on the activities of adults of the cabbage maggot, Hylemya brassicae (Bouché), are scanty, sometimes not in agreement with one another, and usually recorded in conjunction with observations on field ecology. Now that individual insects are being used in studies of resistance in rutabagas (Swailes, 1960) a more detailed account of activities after adult emergence is available. This paper deals with the pre-oviposition, mating, and oviposition 'behaviour of the females and mating behaviour of the males.