Fifteen life tables were compiled from population and mortality data collected in the Quinte area of eastern Ontario during the 5-year period, 1972–76, that spanned the rise and fall of an outbreak of the alfalfa weevil, Hypera postica (Gyll.).

Components analysis of the data showed that a disease of the feeding larvae caused by Entomophthora phytonomi Arthur, a fungus new to the insect in North America, was the principal determinant of intrageneration survival. Multivariate analysis of the separate mortalities, expressed as k-values, confirmed that this agent was the key factor governing population trends of the weevil and was mainly responsible for its population decline.

Examination of the properties of the various mortality factors showed that E. phytonomi was density dependent but overcompensating. Other agents, including the parasitoids Bathyplectes curculionis (Thom.) and Tetrastichus incertus (Ratz.) acted in a density independent manner and contributed little to population trend.

The predaceous mite Balaustium putmani Smiley was studied in the laboratory and in apple orchards in southern Ontario. A rearing technique was devised which facilitated the study of the life history and behaviour of individual mites.

Temperature and moisture influenced the development and hatching of eggs. In the presence of water, development proceeded more rapidly at the higher temperature of the 10°–25°C range tested. In the absence of water no development occurred. Larval B. putmani are free-living predators and although some were observed feeding periodically on pollen grains, they could not survive solely on this diet. All three motile stages are predators of a wide range of small, soft-bodied arthropods, but feed mainly on eriophyids and phytophagous tetranychid mites. The rate of consumption of the eggs and motile stages of the European red mite was determined for each motile stage at 20° and 25°C. Insemination is by externally deposited spermatophores and in the adult females, no facultative parthenogenesis was evident.

Nearly 1300 Lathrolestes nigricollis (Thompson) and 900 Grypocentrus albipes Ruthe (Hymenoptera: Ichneumonidae), were released in Quebec, in 1974 and 1975, in an effort to control the birch leaf-miner, Fenusa pusilla (Lep.). The two species of European parasites were liberated in stands of gray birch (Betula populifolia Marsh.) in four localities of the St. Lawrence River Valley. Mating was well observed for L. nigricollis but not for G. albipes, and both male and female progenies were later recovered for the two species. Three generations of parasitoïds, the first of which overwintered, were recorded at the end of the summer in 1975. Establishment of these parasites of F. pusilla is very likely to occur in the near future.

Orthops rubricatus (Fallén), a European species now known to occur in North America, is transferred to the genus Pinalitus Kelton. Pinalitus solivagus (Van Duzee) is reported from British Columbia, and P. utahensis Knight and P. brevirostris Knight are considered to be synonyms of it. Pinalitus rostratus n. sp. is described from Canada and western United States. Pinalitus californicus Knight is transferred to the genus Proba Distant. A key to species is provided.

The populations of Laspeyresia pomonella (L.) on two cultivars in an insecticide free orchard showed similar trends over a 12-year period. Infestation of fruit was greater on the cultivar with the larger annual crop. Predation of eggs on the cultivar Delicious was greater than on the cultivar McIntosh. Mortality of neonate larvae was greater on McIntosh. Egg-to-egg survival ratios varied from 0.23 to 6.83. The average generation survival of egg to adult for the 12-year period was near 10% which confirms an earlier value established empirically.

Samples of a population of Argia vivida Hagen larvae were taken at about monthly intervals from a series of warm sulphur pools at Banff, Alberta, from June 1973 to December 1974. Changes in head capsule width and wing pad length in field-collected and laboratory-reared specimens show that the life-cycle is univoltine. Only the final (Z) instar can be recognized with certainty, but methods are described whereby the population can be divided into size classes which are thought to correspond well with the last nine larval instars. Periods of rapid growth occur in the autumn and again in the spring. Larvae overwinter in the instars U, V, W, X, and Y and the major shift to the final instar occurs in March and April. Adults emerge from April to August. In the laboratory, growth is temperature dependent until the penultimate (Y) instar and this could be a factor in the field since, although larvae can exist year-round at a constant 26 °C, some larvae live in the cooler areas at the edges of the streams and pools. Entry to the final instar appears to require the long photoperiods that follow the vernal equinox.

As a result of alar tagging migrating specimens of the monarch butterfly (Danaus p. plexippus L.) in North America over a period of 25 years, it was possible to plot the migration routes establishing two large overwintering colonies, one located in California and the other in mountains of the Sierra Madré Occidentale in Mexico. Photographs of the two overwintering populations are presented together with release–recapture lines showing the direction of migration from breeding areas to the two overwintering sites. Data, presented for the first time, show the migration routes of the Western population from the breeding areas in the mountains and west of the mountains to California.

Larvae of the wheat stem sawfly, Cephas cinctus Nort, reduced the weight of grain per head by an average of 17.3% in the two spring wheats Red Bobs and Thatcher with annual reductions varying from 10.8% to 22.3%. They also lowered the protein content in Thatcher by an average of 0.6% and a maximum of 1.2%. However, because a significant loss in protein content occurred in only 1 of 6 years in Red Bobs, the effects of the larvae on protein content cannot be generalized for all varieties.

The losses in weight per head resulted from a mean reduction of 11.9% in the weight of the kernels combined with a mean reduction of 1.9 in the number of kernels per head. The larvae caused the losses by feeding in the stems and by cutting them when the moisture contents of the kernels were relatively high. Annual variations in losses were attributed to the dates of the infestation, to the amount of precipitation in July and August, and to differences in dates of cutting by the larvae.

The spatial distribution of the Egyptian alfalfa weevil larvae using Iwao’s index of dispersion was examined in a California alfalfa field. The changing dispersion patterns with time were found to be influenced by both density induced competition for food and varying spatial distribution of host plants. values characteristic for both years quickly stabilized. This made possible a method for estimating leaf consumption rates by larval populations with an aggregated distribution, k being derived from . Field sampling decision rules were also determined.

Morphological variation between two closely related species in the genus Amblyseius Berlese was examined by numerical taxonomic methods. Multivariate tests indicated that A. canadensis Chant and Hansell and A. novaescotiae (Chant) represent two separate and distinct morphological groups. This supports their taxonomic retention as valid species. Intraspecific morphological variation was also examined and found to be correlated with climatic and host plant variables.