Aphids of the genus Cinara are capable of causing serious growth reduction of Douglas-fir seedlings. Growth of infested seedlings may be only one-fourth to one-half that of uninfested seedlings. The aphids are easily controlled by injecting demeton around the base of the seedling. The presence of ants to clean up excessive honeydew is shown to be beneficial for the aphids.

In southern Alberta, the distribution of Bombus (Bombias) auricomis is confined to wooded areas whereas that of B. (Bombias) nevadensis encompasses prairie and wooded areas. Perhaps B. nevadensis survives on the prairie because it hibernates well below the surface of the soil.

When given equal opportunity to nest in surface or underground hives, B. nevadensis nested in three surface and 18 underground hives. Both species began to establish nests between mid-May and mid-June.

Both species laid one egg per cell in all broods, vertically in the first brood and horizontally in later broods. Larvae were fed individually in all instars of all broods, except perhaps during early instars of the first brood when pollen was packed beneath them through pockets made at both ends of the brood mass.

The eggs in the first brood layer were usually laid within 4 days. The cells beneath the shallow incubation groove were usually the first made and the ones from which adults first emerged. Queens of B. nevadensis required about a month to rear sufficient workers to take care of the foraging duties of the new colonies. Egg cells of succeeding broods were built side by side in groups or lines on cocoons of previous broods and were not primed with pollen.

Both species were prolific producers of wax. More pots for the storage of honey and pollen were added as colonies increased in size.

Colonies of both species were usually small, apparently because the queens usually found time to rear only one brood of workers and perhaps because only one egg was laid in each cell. The largest colony, of B. nevadensis, produced 139 individuals. The workers of a brood sometimes varied greatly in size. The workers of succeeding broods were progressively larger, the last ones produced being almost as large as queens. Males of B. nevadensis mated by grasping the queens when they were flying, then copulating on the ground. After mating, queens hibernated at a depth of about 3 inches in the soil.

Males and females of Psithyrus insularis were reared in nests of B. nevadensis. P. suckleyi also established in a nest of this species. The big-headed fly, Physocephala texana, was a destroyer of B. nevadensis. Ants pillaged first broods not protected with an insecticide.

Parasite studies were carried out in two residual spruce budworm outbreaks in Quebec. Investigations were conducted during the last three years of the outbreak in the Lower St. Lawrence region and during the last year of the one in the Saguenay region. In the Lower St. Lawrence region decline of the insect population was initiated through aerial application of DDT over a period of three years, while in the Saguenay region the unfavourable condition of the forest stands apparently kept budworm numbers below peak outbreak levels. The incidence of mortality through the action of parasites was very high during the last year of both of these outbreaks and probably contributed to bringing about their collapse. Meteorus trachynotus Vier. has repeatedly been recovered in abundance during the last year of a number of budworm outbreaks and it was amongst the important parasites recovered in both outbreaks under discussion. Other species, however, that were abundant in one or the other of these two outbreaks had not been recovered in numbers before. The parasite complex and the relative abundance of each parasite species during budworm outbreaks is fairly constant at the time of peak host populations, but it is now apparent that they vary considerably at the time of outbreak collapse. Variations in the presence and relative abundance of alternate hosts probably account for this situation.

Details of a method of mass rearing eggs and larvae of the cabbage root maggot, Hylemya brassicae (Bouché) for bioassay and of continuous propagation of all stages of the pest are described. The technique was equally suitable for rearing the onion maggot H. antiqua (Meig.), the seed corn maggot H. calicruraliturata (Rond.) and the carrot rust fly, Psila rosa (L.). Under the conditions described, 2000-2500 eggs or first-instar larvae of H. brassicae were obtained from 50-60 female flies in 24 hours, or 1000-1200 mature larvae or pupae were reared from eggs produced by 25 female flies in approximately 20 days.

Agelenopsis potteri (Blackwall) spiders that were reared from egg to adult on live prey (Aedes aegypti L.) supplied at different daily rates varied in the rate that they were able to capture prey, grow, and attain maturity. Mortality varied inversely with feeding rates, but some spiders matured at each feeding rate. All spiders matured in seven stages regardless of the rate of feeding. Both sexes were mature following the sixth moult. The rate of prey capture declined sharply in the adults. Males matured about four days sooner than females. A straight-line relationship exists between the rate at which prey were captured and the dry weights of the adult spiders. A straight-line relationship was also found between the numbers of prey captured per day and the daily development of the spider.

The larvae of Cephalcia fascipennis (Cress.) feed on spruce and occasionally severely damage ornamental trees or hedges. The life history is described.

Larvae of the pale western cutworm, Agrotis orthogonia Morrison, were fed on wheat in the laboratory, greenhouse, and in field plots. Larvae did not completely sever the plants until the third-instar. The rate and amount of damage varied directly with size and densities of larvae, temperatures above 15 °C., and soil moisture; and inversely with the age and size of the wheat plant. The findings were related to field conditions to appraise potential damage and the necessity of insecticides for crop protection. Possible procedures are discussed for evaluation of the efficiency of various chemicals in the laboratory and in field plots.

Group VIII of North American Ips contains I. interruptus (Mannerheim), I. engelmanni Swaine, I. amiskwiensis G. Hopping, I. sulcifrons Wood, I. pilifrons Swaine, I. yohoensis Swaine, I. tridens (Mannerheim) and I. semirostris G. Hopping. Females of some species have dense brushes of long setae or pads of short pile covering the frontal protuberance. Species are described and a key is given. All of them breed in spruce, six in the boreal forest and two farther south in the Rocky Mountains.

The relative toxicity of Kelthane (1,1-bis (p-chlorophenyl) -2,2,2-trichloroethanol), and parathion to Phytoseiulus persimilis Athias-Henriot and its prey, Tetranychus urticae K. (= telarius (L.)), was determined using a Potter Spray Tower. Parathion was found to be far more toxic to P. persimilis than was Kelthane. The LD50 values for Kelthane were 0.051% and 0.29% for T. urticae and P. persimilis respectively, and for parathion were 0.050% and 0.0044% respectively. The LD95 values bore a similar relationship to each other. The two materials were equally toxic to T. urticae. Therefore, use of Kelthane rather than parathion in an environment where P. persimilis and T. urticae were interacting would favour the beneficial species. The statistical aspects of the test method are discussed.

Factors inducing diapause and methods foe breaking diapause in the cabbage maggot, Hylemya brassicae (Bouché), are discussed. The pest was reared continuously in the greenhouse during the winter months (when pupae normally enter diapause) by fluctuating the air temperature from 60 to 65 °F. at night to between 75 and 80 °F. during the day and maintaining the soil temperature (in which the eggs, larvae and pupae were reared) at about 68 °F. Pupae produced by flies kept at constant temperatures entered diapause. Fluctuating the soil temperature (for rearing larvae and pupae) did not markedly influence entry into diapause, but when larvae and pupae were reared at above 72 °F. high mortality occurred. Intensity of diapause in the pupae also depended on the temperature at which the flies were reared, with the shorter period of dormancy occurring when flies were kept at low temperatures. Diapause development proceeded more rapidly at 45-50 °F. than at higher or lower temperatures but proceeded to completion at any temperature from 34 to 70 °F. At above about 72 °F., diapause development appeared to be inhibited. The period for completion of development was about 3-8 months, depending on storage temperatures and on intensity of diapause. Preliminary tests indicated that light intensity is a major factor influencing entry into diapause, and results of tests reported in this paper show that this influence can be offset by temperature.

The trefoil sawfly, Atomacera debilis Say, is reported for the first time from Canada. The larvae are redescribed to illustrate their unusual morphological characters. The known distribution in North America and biological information on the species are presented.

Synergus pacificus McCracken and Egbert (Hymenoptera: Cynipidae) is an inquiline of oak gall cynipids in the Pacific Coast area from southern British Columbia to central California. Approximately 1,000 specimens were examined during the course of this study. Descriptions of the egg and larval stages are given, and information on life history and ecology is presented.

Trachyphloeus Germar, 1817, is judged to be introduced in North America; the two species described from the United States are considered European imports. Consequently, the names T. davisi Blatchley, 1916, and T. bifoveolatus (Beck), 1817, are considered synonymous, as are the names T. asperatus Boheman, 1843, Chaetechus setiger Horn, 1876, and T. olivieri Bedel, 1883. Chaetechus Horn, 1876, is synonymized with Trachyphloeus. T. aristatus (Gyllenhal), not previously reported from North America, is recorded from Carleton Place, Ontario.

Group VII of North American Ips contains I. thomasi, new species, I. borealis Swaine and I. swainei R. Hopping. They are less than 4.0 mm. long and females have the front of the head or at least the vertex smooth and shining, impunctate, or with very fine sparse punctures; males are more coarsely granulate-punctate on the frons. The species are described and a key is given. All breed in Picea in Canada and northern United States.

Parasites of the hymenopterous families Braconidae, Encyrtidae, Eurytomidae, Pteromalidae, and Torymidae are listed from many different species of California Scolytidae. A parasite-host list and a host-parasite list are included to facilitate use of the paper. Forty-two records new to North American literature are presented.

A gynandromorph of Aedes punctor, collected while it was sucking blood, is described and figured.

It has come to my attention that results I reported (DeMars 1963) were incorrect.

In Table I the values for samples 4 through 7 in column 4 (Larvae-Dead-Rad.) should read 1, 10, 7, and 4 instead of 10, 7, 4, and 0. In Table II the values for sample 13 in columns 8 and 12 (Beetles of all stages-Live and Total-Rad.) should read 102 instead of 103.

The incidence of attacks by Dendroctonus ponderosae Hopk. (= monticolae) was recorded by square-foot quadrats from the total bark surface of 60 lodgepole pine trees, Pinus contorta Dougl. var. latifolia Engelm., according to location on the tree, proximity to branches, and degree of bark roughness. The frequency distribution of attack density was bimodal, but the bimodality was an artifact of sampling from a population having a varying mean density. A log (x + 1) transformation of the data permits the use of parametric tests. Alternative non-area sampling techniques showed that the spatial distribution of attacks within a small area tended toward regularity, probably following the distribution of bark niches. The greatest variance in attack density was associated with height, followed by areas, trees, diameters and aspects. Bark roughness was an important influence of distribution but number of branches was not.

The six-spotted leafhopper, Macrosteles fascifrons (Stål), is the only known host of Pachygonatopus minimus Fenton; parasitism has reached 37%. The female adult is also a predator of the leafhopper. In the adult stage of the parasite the sexes differ in form, color and habits; the male is winged and the female wingless. The egg is laid in the abdomen of the host. As the larva develops it protrudes through an intersegmental membrane. There are five larval instars. The first four are sedentary and attached to the host; the fifth is an active feeding stage. The larva spins a cocoon within which it pupates. The period from egg to adult is about 28 days. P. minimus does not provide effective control of the leafhopper.