Distinct differences were observed in postdiapause development and prolonged diapause of the larch sawfly, Pristiphora erichsonii (Hartig), obtained from the vicinity of Tazin River, Northwest Territories; near Riverton, Manitoba; and near Renovo, Pennsylvania. All populations had been reared under controlled laboratory conditions (21°±0.5 °C, 50±10% relative humidity, and a 15-hr daily photophase) for two or more generations.

After 280 days cold treatment at 3°±1 °C, cocoons were dissected and the number of pronymphs and eonymphs was determined. Insects from each population were then reared at 5°, 10°, and 15 °C. Times to adult emergence, duration of individual stages, and numbers remaining in prolonged diapause at each temperature were determined.

The most significant differences occurred among populations reared at 5 °C. At this temperature, the times to adult emergence and the duration of individual stages of development and the proportions remaining in prolonged diapause or arrested development, increased from northern to southern latitudes. Less significant population differences were noted at 10° and 15° than at 5 °C.

Diapause in Hippodamia tredecimpunctata (Linnaeus) can be inhibited by exposing adult females to photoperiod regimens of LD 16:8 or 14:10 hours. Exposing adult females to a photoperiod of LD 12:12 hours initiates diapause. The photoperiod to which the egg, larval, and pupal stages are exposed has no effect on the developmental rate and has little effect on adult diapause status.

Eight species of spiders belonging to two families were collected on northeastern Devon Island, N.W.T., in connection with the Canadian International Biological Program, Tundra Biome. They are Lycosidae: Tarentula exasperans Pickard-Cambridge; Erigonidae: Acartauchenius pilifrons (Koch), Collinsia spetsbergensis (Thorell), Diplocephalus barbatus (Koch), Erigone psychrophila Thorell, Hilaira vexatrix (Pickard-Cambridge), Minyriolus pampia Chamberlin, and Typhochraestus latithorax (Strand). The three most commonly collected species were E. psychrophila, T. exasperans, and H. vexatrix, in that order. New distributional data from other arctic localities for the above-mentioned species are given. A. pilifrons is recorded for the first time from the Nearctic Region and is described and figured in detail.

Deposits of the nuclear-polyhedrosis virus of Trichoplusia ni (Hübner) and of the granulosis virus of Pieris rapae (Linnaeus) were largely inactivated within 10 days after sprays were applied to field plots. Deposits on plants retained in a growth room or in a greenhouse were inactivated but more slowly than those exposed to direct sunlight. Deposits on plants kept in the dark lost little activity indicating that exposure to light was responsible for inactivation.

Activity of deposits of the viruses was extended substantially by addition of protectant materials to the sprays. The addition of charcoal mixed with skim milk powder, egg albumen, or brewer’s yeast resulted in a 3-fold increase in the period over which an LD50 of virus was maintained on the plants.

The Poisson and the negative binomial series, Taylor’s power law, and Morisita’s Iδ-index were used to interpret the dispersion of field counts of the immature stages of Hypera postica (Gyll.) on alfalfa. The data conformed consistently to an overdispersed distribution. Transformations are offered for stabilizing the variance of field counts.

Performance of the pea aphid, Acyrthosiphon pisum (Harris), on a holidic diet containing different metal ions was studied by individually incorporating into the diet a salt of the metal ion to be tested. The performance of the pea aphid was markedly improved when the diet contained iron; the first-generation adults reproduced, and the second-generation nymphs moulted twice or thrice, but did not reach the adult stage. Molybdenum, boron, and copper, at certain concentrations, induced the production of some live nymphs, but manganese, zinc, calcium, and cobalt did not. However, the presence of zinc, cobalt and calcium, at most of the concentrations used, slightly improved growth and reduced mortality. Furthermore, the presence of calcium appeared essential for development to the adult stage. Tolerance to all these metals was fairly high, but sodium molybdate at a concentration of 50.0 mg, and sodium borate at concentrations of 40–100 mg/100 ml of diet, appeared to reach toxic levels.Iron was found to be essential for reproduction and a range of 53–211 μg of elemental iron per 100 ml of diet appeared to be optimum. It is suggested that a synergistic effect between at least some of these metals is required for continuous reproduction of the pea aphid.

Adult fir engraver beetles were examined by serial paraffin sections and scanning electron microscopy. In both male and female beetles small cup-shaped pits covering the top and portions of the side of the head were consistently found to carry fungal spores. These pits usually contained a waxy looking material in which the spores were imbedded. The pits provide a mechanism for fungal transport and storage.

Two bioassays were used to study the effects of the various life stages of a Temperate Zone ambrosia beetle, Xyleborus dispar (F.) (Coleoptera: Scolytidae), on the induction of the ambrosial form of its symbiotic fungus, Ambrosiella hartigii Batra (Fungi Imperfecti).Postdiapause adults and pupae of X. dispar cause a change from the mycelial to the ambrosial form of A. hartigii in culture.

Larvae feed on the mycelial form in vitro, but ambrosia is required by larvae to develop and pupate. One of the main factors inducing the ambrosial form of A. hartigii is probably a secretory product of X. dispar.

The Palaearctic braconid Pygostolus falcatus (Nees) is recorded from Prince Edward Island parasitic on Sitona hispidula F.

Adult black flies were trapped at the townsite of Deep River from the early emergence of Prosimulium spp. (approx. 21 May) through to the late summer decline of Simulium spp. (in August). "Sticky" traps employing CO2 as an attractant were located at five sites throughout the town; in addition a trap was positioned at a "control" site outside the town limits near a heavily forested area. The overall numbers increased rapidly in early June, remaining at high levels until the first week in July, by which time over 110,000 flies had been captured. The numbers of flies recovered both within and outside the town fluctuated widely with weather conditions, seemingly influenced by precipitation. In the town, three centrally located traps captured only half as many adults as two traps near the southerly limits, where a small stream flowed through light forest. The control trap showed that black flies were at least 10 times more plentiful outside Deep River. Three insecticide applications did not have any measurable effect on fly numbers. The predominant local species is Simulium venustum Say.

Perimones britteni (Jackson, 1913) is regarded as conspecific with, and therefore a junior synonym of, Minyriolus arenarius (Emerton, 1911). Hence, Perimones arenarius (Emerton) is Holarctic. Contrary to common usage, Walckenaera spiralis (Emerton, 1882) is not a synonym of W. vigilax (Blackwall, 1853), the former applying to a North American species and the latter to a European. Cochlembolus formicarius sp. n. is described from nests of the western thatching ant, Formica obscuripes Forel, in Washington State.

Paratrichobius americanus new species is described and illustrated from specimens collected in Arizona, from the host bat Choeronycteris mexicana Tschudi It is most closely related to the P. longicrus (Miranda Ribeiro) complex of species, but is easily differentiated from all the known species by details of the chaetotaxy of the profemur, mesonotum and gonapophyses, and by the small eyes. This is the first species of the genus to be recorded from the bat subfamily Glossophaginae, all others are known only from the Stenoderminae (family Phyllostomidae).

Organophosphorus sprays were applied during 1968 and 1969 to an unsprayed but otherwise well cared for apple orchard to destroy the resident phytoseiid predators, Typhlodromus caudiglans Schuster and T. pyri Scheuten. The phytoseiid commonly found in commercial orchards in British Columbia, T. occidentalis Nesbitt, was then released into the orchard.The population density of T. occidentalis increased greatly during 1970 but in the absence of sprays the resident predators reappeared. By the end of the 1971 season, T. caudiglans and T. pyri were once again the main phytoseiid predators and T. occidentalis was relegated to an insignificant role.

Scolytids were collected from snowfields above timberline in Oregon and Washington. The most productive location was Collier Glacier on Middle Sister Mountain, Ore., where 334 specimens representing 20 species were collected on 4 August 1968. Collections from seven mountains comprised 476 specimens, 12 genera, and 26 species. Hylastes nigrinus (Mann.) made up 63% of the specimens collected. The collections demonstrated that bark beetles had been dispersed vertically and horizontally thousands of feet from the nearest possible source. Phloeosinus chamberlini Blkm. was found 15 miles from the closest known host tree. Behavioral and meteorological factors involved in the dispersal of scolytids to snowfields are known only circumstantially. Certain species are thought to fly skyward initially. Some individuals presumably are carried aloft by warm updrafts and their fallout occurs when the air becomes too cool for flight.

This investigation was concerned with fauna above and within the litter, fermentation, and humus layers of the soil in a mature stand of red spruce (Picea rubens Sarg.). The following six microsites were designated for sampling: "open" and "closed" hollows, flats, and hummocks. "Open" and "closed" referred to the space among the tree crowns directly above the microsites. Three sampling techniques, namely core samplers, pitfalls and Tullgren funnels, were employed. Samples were collected weekly from spring to winter in 1966 and 1967 by all methods except that in 1966 Tullgren funnel samples were collectell biweekly. Collected fauna comprised five Phyla, 11 classes, 28 orders, and approximately 124 families. The transformed core sample and Tullgren funnel data were analyzed using an ANOVA (2-way classification) procedure. Transformed pitfall data required an ANOVA (2-way classification, with sampling) procedure. The core sample and Tullgren funnel methods indicated a significant difference (α = 0.10) among microsites based on total weekly (or biweekly) faunal catches in all but one case (which approached significance). In 1966 there were no significant differences (α = 0.10) among the pitfall microsites but in 1967 there were. In all cases there were significant differences (α = 0.10) in the total weekly or biweekly catches of fauna from the various microsites.

The larva of Nomophila noctuella D. & S. is described and illustrated. Five specimens from Germany compared with those from Ottawa, Canada, showed no specific differences.

Mature mosquito larvae of Aedes communis (De Geer) were collected from woodland pools and treated in solutions of 32P. Adults from these larvae were captured using 20 traps employing battery operated lights, and dry ice producing CO2. Trapping was continued for 13 weeks, and a total of 31 radioactive flies were captured during the period. The majority of the radioactive mosquitoes were recovered at the outer limits of the study area of 1 mile, most of them east and south from the release point, and the last tagged individual was trapped 44 days after emergence. Thus, it seems probable that most of the tagged mosquitoes dispersed further than the limits of our study area and that they survived for more than 1 month in the field.

Environmental factors can significantly affect the occurrence of a second diapause in laboratory-reared Choristoneura fumiferana. Each of the following conditions resulted in significantly fewer larvae entering second diapause: incubating the eggs at a high relative humidity (95%); a pre-diapause period at 20 °C rather than 28 °C; a diapause period of 7 or 8 months rather than 4 months; and holding the feeding larvae at higher temperatures (24 °C and 28 °C as opposed to 20 °C). Late-emerging larvae had a greater tendency to enter second diapause.

The alternate generations of five species of gall-making cynipids on Garry oak, Quercus garryana Douglas, have been newly ascertained. Bisexual and agamic generations of each species have been reared through complete life cycles. All have been identified to species; three generations are described for the first time; two new synonyms and one new combination are given.

Morphology of the adults is relatively consistent between alternate generations, but specific characteristics, habitat, and gall-form may differ widely. Distinguishing features of the generations are presented, including life histories, descriptions and photographs of galls, and comments on associate insects. Taxonomic bibliographies are given, and references are listed.