A recent development in microscopy certain to be of great interest to entomologists is the Scanning Electron Microscope. This machine overcomes the difficulties of studying solid surfaces with a standard light microscope and the problems of the extremely small limits of penetration of the electron microscope. This new microscope focuses a stream of electrons into a beam as small as 1 μ in diameter which moves over the surface of the specimen in a regular pattern, causing secondary radiations to emerge from the surface of the specimen. These are collected by a very sensitive detector and converted to an image similar to that produced by a television tube.

When male Anagasta kühniella (Zell.) were released in a wind tunnel downwind of a scenting female they flew upwind, but on losing the scent made crosswind casts and thus located the female. Downwind casts were rare. In still air males approached females from below. Visual stimuli seemed to induce mating behaviour.

In the laboratory, second- and third-instar Plutella maculipennis (Curtis) larvae were about equally susceptible to parasitism by Diadegma insularis (Cresson) or by Microplitis plutellae Muesebeck. The fourth and last instar was less susceptible than the second and third. Larvae of the first instar, although usually within the tissues of the food plant, could be parasitized. Maximum progeny obtained from female parasites during a lifetime, with regularly renewed supplies of hosts, averaged 516 in D. insularis, and 232 in M. plutellae. Effectiveness of D. insularis among a given number of host larvae improved slightly, reaching 85/100 as cage size increased from 50 to 200 sq. in., and declined somewhat, from 124/200 to 94/200, when cage size was further increased from 200 to 1500 sq. in. In field cages of 1, 2, and 4 sq. yd, with 200 host larvae, single female D. insularis parasitized about 35, 20, and 7% of hosts respectively. With 50, 100, 200, and 400 host larvae in 200-sq.-in. cages, and one female per unit, average progeny of D. insularis were respectively 39, 70, 113, and 150; of M. plutellae, approximately the same. In competition, two females, one of each species, operating among the same lot of larval hosts, produced more total progeny than two of the same species. Increasing constant temperatures from 20° to 30° favoured D. insularis slightly, but viability and effectiveness of M. plutellae at 30° was reduced.

Three new Cryptinae (Ichneumonidae: Hymenoptera) are described from Canada: Cryptus leechi from Arctic Canada and northern Greenland, Mastrus laplantei attacking Diprionidae and Lepidoptera from coast to coast in the lumbering areas, and Medophron dytiscivorus from a Dytiscidae pupa in Ontario.

Current methods of sampling predator and prey populations on apple trees use two different indexes to measure the comparative abundance of each. Techniques are sought that relate the proportions of one to the other in the sampling universe (the orchard) in a quantitative manner. The most important criterion is that the sampling unit be one common to both predator and prey species and encompass representative portions of the habitat of each. The whole tree meets this criterion but it is too cumbersome to sample in toto. The large limb was, therefore, appraised for feasibility as a basic sampling unit common to many species. All clusters were counted and the predators and prey expressed as numbers per 100 clusters. The whole limb was examined for insect predators but only a representative portion of it was used in estimating mite populations. The test prey species was the European red mite, Panonychus ulmi (Koch), and the predators a small number of active insect species, mostly Diaphnocoris pellucida (Uhler) and Anthocoris musculus (Say). It was found that the numbers of mites on randomly chosen clusters from a limb were representative of the total population of mites on a limb but the associated variation was high. Samples of relatively uniform (standard) clusters of good vigour overestimated the mite population. Some other causes of variation were also examined and are discussed. A 2-year orchard test showed it was feasible to estimate the abundance of both mites and predators on a common basis and thus obtain a measure of the ratio of mites to predators in the sampling universe.

One parasitic dipterous species and 27 parasitic hymenopterous species were collected. Parasites were primarily collected by mass-rearing host larvae on cut host plant foliage in the laboratory or by rearing larvae on artificial diet. The tachinid Nemorilla pyste (Walk.) and five hymenopterous species, Glypta n. sp. (Ichneumonidae), Campoplex sp. (Ichneumonidae), Agathis acrobasidis (Cushman) (Braconidae), Elasmus atratus How. (Eulophidae), and Catolaccus aeneoviridis Girault (Pteromalidae), were definite parasites, and biological notes are given. Collection data are also given for the other 22 species.

One reduviid predator, Zelus socius Uhler, and six spiders were observed feeding on C. houstonana.

Two species of ants, Formica obscuripes Forel and Dolichoderus (Hypoclinea) taschenbergi (Mayr), attended species of Cinara, mainly C. gracilis (Wilson) on Pinus banksiana Lamb., in the Sandilands Forest Reserve, Man. The aphids occurred only on trees near ant hills. Removing the aphids by spraying had no serious effect on the ants. Destruction of an ant colony was followed by the disappearance of the aphids. The trees benefited through removal of defoliating insects by the ants.

The pinyon pine sawfly, Neodiprion edulicolus Ross, has periodically caused serious defoliation of singleleaf pinyon, Pinus monophylla Torr. and Frem., in the Intermountain Region. Infestations have been short-lived, however, and widespread tree mortality has not been known to occur.

The first recorded outbreak of N. edulicolus in the Intermountain Region was detected in 1959 along Nores Truck Road near Pioche, Nevada. Mortality of smaller trees occurred. Population levels were low in 1962, 1963, and 1964.

Over 100,000 acres of pinyon pine in the same general area near Pioche and near Caliente, Nevada, were heavily defoliated in 1965 and 1966. Most of the pinyon were rendered unfit for sale as Christmas trees.

The life cycle and stages are typical of Neodiprion species. Eggs overwinter in pinyon needles; eclosion commences in April and is completed by mid-May. Feeding larvae develop through four to six instars; ultimate instars drop to the ground and spin cocoons underneath duff and in sandy soil beneath the host trees in June. Prepupae spend the summer in the cocoon, pupate in the fall, and adults emerge in October and November to mate and oviposit.

Unfavorable climatic factors, followed by heavy parasitism of the remaining larvae, reduced the sawfly population to a low level near Pioche in 1960, and near Caliente in 1966.

The distributions of Scolytus ventralis LeConte attacks, emergence, and parasites were studied by stratified sampling of 20 grand fir. Of the theoretical distributions tested the negative binomial gave the best fit to all three sets of data. Three sample unit sizes were analyzed (1/4, 1/2, and 1 sq. ft) and all gave similar estimates of the mean, although the smallest sample unit influenced the distribution by increasing the frequency of the zero class. Approximate normality was achieved by applying logarithmic transformation to the attack data and the Taylor power transformation to the emergence and parasite data. Analysis of variance showed that the vertical position of the sample in the tree was die most consistent factor influencing the distribution of attacks, emergence, and parasitism, while cardinal aspect had little effect. Considerable variation also occurred among trees within a group. The density of attacks was extremely variable both within and between trees, although it was slightly higher on rough bark. Emergence was generally greater in the basal half of the tree, being reduced in the upper levels by competition with other insects. Emergence increased with attack density up to about 13 attacks per square foot. Thereafter survival was probably limited by intraspecific competition. Parasitism appeared to be reduced near the base of the tree by thick bark and at the top by lack of host larvae.

Sampling designs for the fir engraver will have to consider variations between trees and vertical strata within the tree.

Uric acid accumulation in the fat body of several species of Tenthredinidae and Diprionidae was determined on a qualitative and quantitative basis. Variations were found in the number of crystal agglomerations per cell and in the nature of the agglomerations between species. Uric acid dosage revealed considerable variations in concentration. Such variations could be useful for taxonomic purposes.

G. cerea larvae feed upon the ovules and capsule of Pedicularis canadensis. Distribution of the fly coincides closely with its plant host. Adult flies are active in spring during the plant’s flowering period. Both sexes of flies are predaceous on small insects. Details of mating and oviposition behavior are elaborated. After feeding, larvae form puparia in the soil around roots of the host and undergo protracted diapause. All activities of the single generation per year are closely attuned to host plant’s cycle. Distribution of G. incisurata appears to closely follow that of its hosts. Larvae feed upon the flower parts of three species of Penstemon (hirsutus, digitalis, and calycosus). Duration of adult and larval activity periods along with behavior closely parallels G. cerea. In view of known host plant preferences in the Scatophaginae, it is suggested the way in which adaptation of Gimnomera to members of the Scrophulariaceae has been established is via the parasitic or hemiparasitic members of this plant family.

The genus Decanematus is recorded for the first time in North America, and a new species D. dulichus is described. A key is provided for the three known species.

Pairs of adults of Trogoderma parabile Beal were held in glass vials and provided with one of seven types of oviposition sites. Among the types of oviposition sites tested, the highest mean egg production was recorded on cotton balls and the lowest in empty glass vials. Egg production was not increased by adding food to vials that contained cotton balls. A suitable oviposition site, which provided crevices for insertion of the ovipositor, was more important than food in stimulating egg production. Non-ovipositing females lived longer than productive females on the various oviposition media. Adults fed, but did not require food to lay eggs. Mated females laid practically the same number of eggs during the oviposition period whether or not males were present.

A controlled environment cabinet for the study of insects or plant–insect interactions which has a novel air velocity control mechanism is described. The useful working space is 0.56 × 0.84 × 1.83 m long and the temperature in this area can be selected from 18° to 35°C at air velocities ranging from 1.5 to 18.0 km/hr. Fluorescent lamps provide a light intensity of 32,300 lm/m2, 0.32 m below the lamps.

Temperatures were controlled within ±0.67°C and the air velocity was uniform within 20% throughout the working area.

The life history of the Sitka spruce weevil, Pissodes sitchensis Hopk., is described. Adults overwinter in duff at the base of trees and emerge in April or early May. Oviposition begins in late April on leaders. The larvae hatch and mine downward, eventually girdling and killing the leader. Larvae pupate in chip cocoons under the bark. Newly developed adults start emerging in August and, prior to hibernation, feed on leaders of young trees. Adults have been observed in the field as late as December.

Predators caused heavy mortality but the weevil population maintained itself and increased in some years. Parasitism was light. Natural control factors reduced the population level but were incapable of controlling a population. Satisfactory control was obtained by applying DDT and phosphamidon to leaders with a hand-sprayer early in the spring, but repeated applications would be necessary to protect a plantation through the critical years.

Damage to Sitka spruce regeneration and plantations in British Columbia is severe. At present, protection of Sitka spruce plantations would require considerable expense.