Factors which influence the rate at which Philodromus rufus Walckenaer attacks prey are discussed. Drosophila melanogaster Meign. was used as prey throughout the rearing and testing of P. rufus. Spiders used in these tests were immature at the time of capture and reared to the adult stage in the laboratory. Feeding histories were maintained for all spiders, although the experiments designed to measure the attack response of individual spiders to changing prey density were done with adult males.

In the immature stage there was no difference between the feeding rate of male and female spiders. The adult males, however, were relatively inefficient predators; females killed approximately six times as many flies in their adult lives as males. The irregular feeding pattern of the females, as compared to the fairly uniform feeding pattern of the males, resulted in the males being more amenable to experimental tests. Periods of starvation, molting, and opposition strongly influenced the feeding rate of P. rufus. At high prey densities there was an inverse relationship between hunger and utilization of individual prey. This resulted from uncaptured prey interfering with the feeding spider.

Both feeding time and searching time showed a relationship to prey density. Individual fly activity increased with fly density and this resulted in a functional response curve with an increasing slope. One of the basic requirements for regulation was thereby demonstrated. When prey density was corrected for the increase in fly activity by computing a new density estimate based on fly activity, a typical functional response for invertebrates became evident for hungry spiders but not for well-fed spiders. By using Holling's “disc equation” the difference between starved and satiated spiders was explained as an interaction between prey and predator characteristics. Owing to density-dependent parameters such as prey activity, predator feeding time, and “rate of discovery”, no known mathematical model fitted the data.

The quinoxalines, Eradex and Morestan, were found to be very effective miticides in laboratory and orchard experiments with the latter the most toxic. Applied at the pink stage of apple bud development Eradex and Morestan gave excellent control of European red mite, Panonychus ulmi (Koch), and delayed the build-up of the apple rust mite, Vasates schlechtendali (Nal.), and the McDaniel spider mite, Tetranychus mcdanieli McG. Both miticides were also very effective when applied in summer. The rates of use for Morestan were established at 8 to 16 ounces of active ingredient per acre in concentrate sprayers and at 2 ounces per 100 gallons in handgun sprayers and at twice these rates for Eradex. Where Eradex or Morestan were the only miticides used in an orchard for four years, the control of the European red mite and the McDaniel spider mite was excellent, an indication that selection of a resistant strain had not occurred. Morestan was highly toxic to the predaceous phytoseiid mite, Neoseiulus caudiglans (Schuster). Morestan has not injured fruit or foliage when applied at the pink bud stage but has marked fruit when applied in summer especially when applied by high-volume handgun sprayer.

Hyposoter parorgyiae (Vier.) (Hymenoptera: Ichneumonidae), a parasite that emerges from the mature larva of Parorgyia plagiata (Wlk.) (Lepidoptera: Liparidae), was found to have a false cocoon. The twelve specimens examined were collected in Ontario and Quebec, and are in the Canadian National Collection, Ottawa, Ontario.

All the Provancher species of Formicidae have been synonymized. However examination of the types shows that three species were new at the time. But one of them was a primary homonym. A new synonymy and a new combination are proposed.

Emergence of apple maggot adults, Rhagoletis pomonella Walsh, under field conditions at Guelph, Ontario, revealed that most maggots emerged from the apples between 2 July and 11 August. However, 12 of 673 emerged benveen 17 August and 16 September. Because this extended period of maggot emergence creates problems in visual certification of maggot-free export fruit, attempts were made to find a more effective trapping method than the use of bait pails for appraising maggot infestations.

Six genera are recognized in the tribe Ammophilini: Ammophila, Podalonia, Eremnophila, Eremochares, Hoplammophila and Parapsammophila. A synonymical species checklist is given for the last three genera. A key to genera is provided which is based partially on characters heretofore unutilized.

Conophthorus lambertianae broods within cones in sunny places on the ground can be killed by high temperatures. This conclusion is supported by experimental evidence from four sources: (1) mortality of broods in cones placed in the sun; (2) mortality of cone beetles exposed to high temperatures in the laboratory; (3) measurements of internal cone temperatures occurring in nature; and (4) consideration of some factors that influence internal cone temperatures.

Field-rearing studies of Camnula pellucida (Scudder) conducted at Saskatoon from 1960 to 1962 indicated that marked differences often occurred in rate of development, survival and fecundity because of differing weather patterns. Grasshoppers usually developed more rapidly as they hatched later in the season when temperatures were rising. In addition, striking differences occurred in growth rates of grasshoppers hatched on similar dates in different years due to sharply contrasting climatic conditions. Although survival of nymphs was generally high, mortality was consistently greatest during early nymphal life. Precipitation or excessively hot weather during this period increased mortality considerably, yet did not affect the older nymphs. Survival of adults was also generally high whether they fledged early or late in the season. They were able to endure very high temperatures during mid-summer or below freezing temperatures during late autumn. The three-year average reproductive capacity of this grasshopper was approximately eight egg-pods or 176 eggs per female. The rate of oviposition varied with temperature, reaching a maximum per female of approximately one pod every four days during mid-summer when temperatures were high and declining thereafter as temperatures dropped. The average egg-pod contained 22.13 eggs which showed a tendency to increase as adults fledged later in the season.

It is suggested that climatic conditions frequently play a decisive role in the short-term modification of grasshopper infestations as well as in the long-term cyclic rise and fall in populations; consistently favourable or unfavourable conditions throughout the grasshopper cycle could result in an explosive outbreak or in almost complete elimination of any threat to the crop.

A worker-like gynandromorph and worker honey bee (control) were observed for similar periods each day from age 4 to 26 days. The gynandromorph behaved more like a worker than a drone bee.

Interspecific pairing of closely related species of Ips and Orthotomicus was undertaken to test their degree of breeding isolation. Pairings of the following species frequently resulted in sperm transfer but no eclosion: Ips mexicanus × I. concinnus (group I), confusus × montanus (group IX), plastographus (group III) × pini (group IV) and Orthotomicus latidens × O. sabinianae.

Mating was generally unsuccessful when the more distantly related species, confusus × plastographus and confusus × pini, were paired.

Individuals which produce all-female broods were discovered in a population of O. latidens. About 50% of the eggs deposited by these females hatched, whereas 92% of the eggs from “normal” females produced larvae.

Cytological investigations revealed no constant differences between the karyotypes of I. mexicanus and concinnus (7AA+Xyp), O. latidens and sabinianae (9AA+Xyp), or between I. confusus and montanus (15AA+Xyp). I. pini (oregonis) and plastographus also have karyotypic formulae of 15AA+Xyp, but both are easily distinguished from confusus and montanus and an atypical chromosome in pini (oregonis) distinguishes it from plastographus. The mexicanus and concinnus karyotype and that of O. latidens and sabinianae can be directly derived from each other by fusion or fission. Their relationship to the karyotype of the European species O. proximus (6AA+Xy), is plausible but their karyotypes are composed of a remarkably different number of autosomal arms from those known for other species of Ips.

A three-year study on the seasonal occurrence of ground beetles was conducted in five fields with different crop rotations. More than 10,000 individuals representing 102 species were captured in pitfall traps. The relatively high total number of species collected the first year probably resulted from the particular location of the traps along field margins and close to woodlands. The variation observed between the areas studied was not necessarily related to the kind of crop. A progressive augmentation in beetle activity and population appeared to coincide with an increase in the humidity of the habitats and with the cultures in the following order: pasture grass, forage, cultivated, and cereal crops. This indicates that the nature of the crop influences beetle numbers, and from this it may he inferred that it also influences the extent to which the beetles exert a control influence on pest species. Of the eight species present every year and found in practically every field, Pterostichus melanarius Ill., Harpalus pennsylvanicus DeG., and H. compar Lec. were the most numerous.

Small females of the parasite Nasonia vitripennis (Walk.) parasitized fewer hosts (housefly, Musca domestica L.) than larger ones during their lifetime because they had both a shorter life span and a lower rate of parasitization. The latter resulted primarily from a lower egg maturation rate. As females reared from superparasitized hosts are on the average smaller than those reared from non-superparasitized ones, these effects of parasite size reduce the rate of increase of N. vitripennis at high parasite:host ratios and result in greater stability in the interaction between the two species.

Species of Tetraphleps Fieber known from North America are canadensis Prov., pilosipes Kelt. and And., feratis (Dr. and Har.), latipennis Van D., and uniformis Parsh. Descriptions, host plants, and distributional records for the species are given, and a key is provided.

A new species, Hypolithus pallidus, from Nevada, California, and Arizona is described and illustrated. This species is not closely related to any other in the genus.

Two species of Apidae occur on Ellesmere Island: Megabombus (Megabombus) polaris (Curtis) and M. (M.) hyperboreus (Schönherr). Some observations on their activity are presented. Three nests built on the surface of the ground are described. The colonies were of small size. Nest No. 1 contained only polaris; Nests Nos. 2 and 3 contained polaris workers and hyperboreus sexuals, as adults or brood. Usurpation is suggested to explain the workerless condition of hyperboreus in Nests Nos. 2 and 3.

Females of I. conquisitor were conditioned to associate colour with the presence of hosts. Conditioning was important only during searching and did not affect the distribution of attacks once hosts were found. The ability of this species to associate colour with the presence of hosts could increase its efficiency as a parasite. Females of I. conquisitor showed an innate preference for blue over yellow.