Geocoris bullatus (Say) adults were observed on two separate occasions dragging adult flea beetles over the soil surface, with one of the flea beetles being identified as Phyllotreta striolata (F). No predation was seen on other occasions when this predator and flea beetles were present together in the field, nor in laboratory confinement experiments. Under the latter circumstances G. bullatus readily attacked aphids, however. It seems likely that G. bullatus is only an incidental predator on adult flea beetles in western Canada.

Studies of the biology of carabids have been limited by the difficulty of sexing living individuals. Mitchell (1963) described the dissection of adults of two carabid species and stated that the aedeagus of the adult male is visible at all stages of maturity.

Differences were shown in the rate of larval development of the fly Agria housei Shewell reared axenically at 15° and 30°C on chemically defined (meridic) diets with varied proportions of glucose and an amino acid mixture. Although the rate of larval development differed with amino acid level and rearing temperature, the important finding was an interaction between glucose and suboptimal low levels of amino acids that occurred in suboptimal low (15°C) temperature. This shows that nutritional requirements can change with temperature and is noteworthy because any relationship between the nutrition of an organism and environmental temperature can have ecological significance.

Observations on the nuclear polyhedrosis viruses affecting six different insects are reported. Of these, one has not been previously reported, and three others have had only minimal mention in the literature with no details given. In this paper, the viruses are illustrated by electron micrographs. The dimensions of the virus particles and other pertinent details are reported.

It is difficult to estimate numbers of small active insects, particularly predators, in fruit-tree canopies because of the frequent and rapid movement of these species. The conventional method of sampling such populations requires tapping the branch to dislodge the insects which fall to a cloth tray from which they are recovered and counted. However, many species take to flight very rapidly and escape before identification is possible. A sampling method was required which would rapidly enclose a volume of the canopy without disturbing the resident population, thereby eliminating inaccuracies in the sample obtained. This note describes a remotely operated mechanical trap which can be placed on a limb in the tree canopy. The insects thus trapped can be immobilized, counted, and identified.

DESCRIPTION. Adult. Male antennae simple, with short, fine cilia evenly and thickly distributed over the entire ventral areas. Palpi medium length. Forewing with ground colour light cream-grey. Antemedial and basal lines faint, grey-brown. Distinct wavy light line, divided by a fine postmedial line, formed between inner margin of subterminal area and outer margin of medial area. Terminal and subterminal areas combined into a grey-brown band with rust-brown spots between veins at the outer margin. Discal dot prominent. Hind wing pattern similar to that of forewing but more blurred. Wing expanse, with forewings fully extended, 20–22 mm.

Descriptions and figures of five undescribed species are presented: Lachlania talea, L. iops, Epeorus (Iron) packeri, Rhithrogena notialis, and Heptagenia bella. Heptagenia mexicana Ulmer is tentatively transferred to the genus Stenonema, the nymphal stage is described for Isonychia sicca manca Eaton and Homoeoneuria salviniae Eaton, and new collection records extend the known distributional range of Dactylobaetis mexicanus Traver & Edmunds, D. musseri Traver & Edmunds, D. zenobia Traver & Edmunds, Isonychia sicca manca, Homoeoneuria salviniae, Epeorus (Iron) metlacensis Traver, and Stenonema mexicana.

Several predator–prey models are examined to assess the generality of Volterra’s contention that an external mortality imposed simultaneously on both predators and prey results in a decrease in predators and an increase in prey equilibrium numbers. The models indicate that this phenomenon occurs mainly as a result of the lack of predator crowding. If predator crowding occurs, a strong functional response of predators to prey density, or light prey mortality relative to predator mortality, is required for Volterra’s phenomenon to occur. In increasing populations away from equilibrium, numerical results indicate conditions for Volterra’s phenomenon to occur.

Hemocytes of Lambdina fiscellaria fiscellaria (Guen.) were examined as suspended cells or as slides from a culot. Five types of hemocytes were identified: prohemocytes, plasmatocytes, granular hemocytes, spherule cells, and oenocytoids. The low numbers of prohemocytes and oenocytoids, the significant decrease in the number of plasmatocytes in last larval stages, and the corresponding increase in granular and spherule cells have been compared with existent literature. Total hemocyte counts were also made.

Dimilin® 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)-urea is an insect growth regulator which disrupts the insect's molting process. It has been field tested against eastern spruce budworm, Choristoneura fumiferana, with variable results (Dimond 1975; Retnakaran et al. 1976). In addition to fluctuations in many field parameters, innate variations in susceptibility to Dimilin during different stadia may influence efficacy. Retnakaran and Smith (1976) found that larvae during the 5th and 6th stadia were most susceptible.

The maximal emergence of Pissodes notatus (F.) adults takes place during July and August. It results from the different evolution of two populations:

— a first population, whose complete development (from egg to adult) takes 11 or 12 months. This population corresponds to eggs laid after the middle of July (maximum egg laying during September). Most of the larvae having reached the third instar, it shows no more evolution during the winter; the further development takes place during the next spring, and adults emerge from mid-June to mid-July.

— a second population resulting from egg laying, between February and July, of hibernated adults (maximum egg laying during April and May). The whole development being very short (2 to 3 months), the adults, corresponding to these eggs, emerge from the middle of July to the end of August.

The observed differences between durations of the under-bark development (from 2 to 12 months) appear free of diapause and probably result from rates of development changing with temperature and instar.

In our regional field temperature conditions, all the individuals reach finally their under-bark development approximatively at the same time, so that the adult emergence period takes place in July and August.

A simple bubbler for separating insects and other macroinvertebrates from aquatic bottom samples by elutriation is described. The apparatus is simple in construction and use and separated all groups of aquatic organisms from stream bottom samples with about 99% overall efficiency.

The mosquito Toxorhynchites rutilus septentrionalis (Dyar and Knab) is recorded for the first time in Canada. The species was found breeding in a water-filled rot cavity in a tree in the deciduous forest of Point Pelee National Park. The distribution of the species for which this record represents an extension of the range is discussed.

Morphological features of the eggs of Euxoa campestris, E. declarata, and E. rockburnei, the “declarata group”, were diagnostic for the species; the esterase zymograms of the eggs of campestris and declarata support the morphological findings. Chorionic features and the esterase zymograms of a hybrid resembled those of the female parent.

During the summers of 1973 and 1974 examination of field collected samples of the spruce budworm, Choristoneura fumiferana, revealed the presence of a Pleistophora sp. (Wilson 1975). It has subsequently been determined as Pleistophora schubergi (Weiser 196 1 and pers. comm.). This microsporidium also appeared in laboratory cultures of the forest tent caterpillar, Malacosoma disstria. M. disstria is often infected in nature by the microsporidium Nosema disstriae. Preliminary tests were undertaken to compare the effects of these two microsporidia on the development of the forest tent caterpillar.

Bioenergetic studies on populations of the two-striped grasshopper, Melanoplus bivittatus (Say), and the red-legged grasshopper, M. femurrubrum (De Geer), at a natural grassland site in Ottawa in 1971 and 1972 indicated that the former species ingested 0.42% and the latter 0.44% of the green shoot primary production (3057 kcal/m2). An additional 1.22 and 1.30% of this production were cut and dropped by the grasshoppers, so that a total of 1.64 and 1.74% of the green vegetation was removed by M. bivittatus and M. femurrubrum, respectively. These two species assimilated 41 and 35% of the ingested food, the remainder being voided as faeces. Respiration accounted for 62% of the energy assimilated by M. bivittatus and for 63% of that assimilated by M. femurrubrum. Approximately 0.06% of the energy of primary production was converted by each species into body and was available to higher trophic levels. However, 94% of the potential energy of the green vegetation removed by the grasshoppers was returned to the "decomposer compartment" of the ecosystem, with only 6% removed or lost from the system.

The effect of temperature on the age-specific fecundity and the survival of apterous and alate virginoparous pea aphid, Acyrthosiphon pisum (Harris), from Kamloops, B.C., was measured. Demographic statistics were estimated for 10.3°, 14.8°, 19.7°, 26.1°, and 27.8°C constant and for fluctuating field temperatures. On a 24-h-day time-scale, temperature and longevity were inversely related in both morphs; total fecundity was highest at average and low constant temperatures. On a physiological time-scale, the intrinsic rate of increase (rm) was insensitive to changes in constant temperature in the range between 10° and 20°C; temperatures above 25°C were detrimental to aphid population growth and survival. Alate virginoparae generally had a longer pre-reproductive period and achieved a lower mean total fecundity than apterae maintained under identical conditions. The usefulness of laboratory measurements for the prediction of population growth under variable field temperatures is discussed. Differences in the reproductive patterns of alate and apterous pea aphids are considered in the context of the r- and K-hypothesis of selection.

Many species of Lepidoptera, especially cutworms attacking forage, cereal, and oilseed crops, pupate in the soil. Most parasites leave their hosts after they enter the soil and so field collections are an excellent source of healthy pupae and parasite cocoons. Previous methods of obtaining adults involved collecting pupae by placing shovelfuls of soil on screens on a mechanical shaker and removing the exposed pupae. This was suitable for the harvesting of only a few dozen pupae as the capacity of the shaker was limited. A more efficient method of exposing them was required. We describe here a technique which we have used for large-scale collections.

Cortical blister and wound reaction resin vapors from Abies grandis, and some of their monoterpene fractions, were quantitatively bioassayed for attractiveness and repellency to the fir engraver beetle, Scolytus ventralis. All were found to be repellent.

Quantitative differences between liquid resins and vapors were examined. Wound reaction resin vapors contained higher percentages of the more repellent monoterpenes than cortical blister resin vapors. It is hypothesized that α-pinene is the most important monoterpene in the insects’ perception of a resistant host.