The divergens group of the genus Euxoa Hbn. is defined, and a new species, Euxoa sinelinea, is described from Goose Bay, Newfoundland, and from Smoky Falls and Black Sturgeon Lake in north-central Ontario.

Group IX of North American Ips contains I. grandicollis (Eichhoff), I. confusus (Leconte), I. montanus (Eichhoff), I. cribricollis (Eichhoff) and I. lecontei Swaine. I. chagnoni Swaine is made a synonym of I. grandicollis (Eichhoff). Ips of Group IX differ from other Ips by having five spines on each side of the elytral declivity. Species are described and a key is given. They breed in various species of Pinus and most of them occur south of the boreal forest.

In a creek northwest of the Gatineau Hills (Quebec) larvae of Chironomidae (Diptera) were found living in phoretic association with the immature stages of Perlidae (Plecoptera). The larvae were reared to the adult stage in the laboratory. Life pattern and morphological comparisons are made with other phoretic and parasitic forms of Orthocladiinae and with certain other genera, and it is concluded that the form represents a new genus and species of Orthocladiini, and has probably originated from the common ancestors of the genera Rheocricotopus, Paracricotopus and Microcricotopus. Detailed descriptions are given of the imago, pupa and larva of this insect.

Uni- and bi-voltine strains of the eumenine wasps, Rygchium leucomelas (Sauss.), Ancistrocerus catskill albophaleratus (Sauss.), A. c. catskill (Sauss.), and A. tigris tigris (Sauss.) occur in the Black Sturgeon Lake region of Ontario. Another eumenine, Symmorphus cristatus cristatus (Sauss.), is univoltine. All the eumenids plug and divide their nests with partitions of clay. Generally, females emerge from cells larger than those of males. A double partition with an intervening space between cells is introduced occasionally in summer-generation nests and frequently in overwintering-generation nests. Generally, individuals of the bivoltine summer generations were predominantly female but overwintering generations were predominantly male.

All eumenine wasps, except S. c. cristatus, provision their nests with lepidopterous larvae. A broad spectrum of prey was utilized but at any given time the female wasp shows considerable fidelity in searching for prey on a given host plant.

Limited parasitism of the eumenids by the genus Chrysis and the ichneumonid genus Ephialtes was observed. The dipteran Amobia distorta Allen was found in nests of A. c. catskill and R. leucomelas.

A single species of pompilid, Dipogon sayi sayi Banks, occupied the trap nests in small numbers. The prey of this wasp consists mainly of spiders in the genus Xysticus.

The sphecids include Passaloecus ithacae Krombein, which was common, an unidentified Pemphredon sp., and Passaloecus mandibularis (Cr.). P. ithacae provisioned mainly with aphids of the genus Cinara; Pemphredon sp. utilized C. abieticola; and P. mandibularis preyed upon a wide range of species including several aphids from deciduous trees.

Partitions in Passaloecus nests were primarily resin but female P. ithacae often incorporated chips of pith. Cell sizes were frequently out of proportion to the volume of prey and the size of the wasp larvae. Limited parasitism by the chrysidid genus Omalus and the ichneumonid genus Poemenia was noted.

In the laboratory, it has been found that females of R. pomonella (Walsh) mating frequently throughout their lives laid about twice as many fertile eggs as females allowed to mate only a few times during their first two weeks after emergence. However, mating had little effect on the total numbers of eggs laid. Females mating frequently averaged 395 eggs and 95% were fertile whereas those mating only a few times averaged 360 eggs and 46% were fertile.

Laboratory studies were conducted with the carrot rust fly, Psila rosae (Fabricius), to determine the effect of irradiation on reproduction. Irradiation of 15-day-old pupae with 1.4, 2.8 and 4.3 kiloroentgens did not adversely affect emergence. Treated females caged with normal males laid a few sterile eggs when the treatment was 1.4 kr. but none at the higher doses. Normal females caged with treated males laid a normal complement of eggs, and the per cent hatch was 10, 2 and 0 with treatments of 1.4, 2.8 and 4.3 kr., respectively. When flies of both sexes from pupae treated at 3.0 kr. were mixed with normal flies in a ratio of 6:1, the number of larvae were reduced by 93%.

The present work demonstrates how important food quality is to an insect. When the dietary inadequacy in an artificial food was dilution of its nutrient content to 85, 70 and 50%, respectively, fifth-instar Celerio euphorbiae (Linnaeus) ate progressively more food but they gained no more body weight on one diet than on another. The rate of food intake depended on nutrient concentration. On all nutrient levels the larvae were about 20% efficient in converting the foodstuff into body material and the body content of protein did not differ significantly.

When the dietary inadequacy was immoderate proportions of several nutrients, the effects were not so clearly marked; nevertheless, the rate of food intake of the larvae could explain their body weight. The tendency seemed to be for the larvae to eat less and to gain less weight on the imbalanced diet than on an adequate diet. Moreover, conversion of foodstuff into body material did not seem as efficient on the imbalanced diet as on the control.

The ecological significance of food quality suggested by the first example is that the destructiveness of phytophagous insects, for example, may depend in part on the degree of succulence and corresponding nutrient concentration of food plant tissues; and by the second example, that perhaps nutritional imbalances may play a part in controlling the potential destructiveness of insect populations.

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

Capacity to adjust to variable resources of food is a useful criterion for assessing the regulatory influence of predators on the population of prey. Anatis mali Auct. was better adapted than Coleomegilla maculata lengi Timberlake to tolerate a shortage of food. When the food supply was increased, survival and adult weight increased in both species – adult weight to a much greater extent in A. mali than in C. maculata, and developmental time decreased in A. mali, but was unchanged in C. maculata. C. maculata was better able to withstand regularly occurring periods of intermittent feeding than a shortage near the end of its development.

The conversion ratio of third-instar A. mali larvae and the growth rate of C. maculata larvae were higher when individuals were fed on Acyrthosiphon pisum (Harr.) than on Rhopalosiphum maidis (Fitch). Between the minimum food requirement and the maximum quantity eaten, the conversion ratio of A. mali decreased whereas that of C. maculata remained constant except at the highest quantities of food where the rate of intake increased and the ratio decreased. Relative food intake rate is an accurate criterion for comparing stages and species of predators that are fed on various foods.

In all but the flattest terrain, differences in relief produce recurrent and consistent patterns of cloudiness during turbulent or convective weather. The basic patterns consist of fixed patches or lines of low clouds that persist in an otherwise clear sky. But their outlines may even appear in the higher layers of cloud that cross the region during the passage of larger weather systems. Consequently, the areas beneath them experience predictably higher frequencies of cloudiness and rainfall than the terrain outside their borders. Thus their outlines can be used to draw boundaries that separate areas with different climates.

The information above can be used to develop a system of direct observations of changes in local weather that can be applied in several ways during studies of natural populations. Visual methods of observing the weather are always simpler than methods that involve instruments. Where population phenomena are concerned, they also may be more meaningful; and they leave more time free for biological observations. Instruments are essential, however, in any investigation of the properties or requirements of individuals; e.g., in physiological or behavioral studies.

A lightweight, economical container used for long-distance shipment of adult Hymenopterous parasites of the Siricidae, and their hosts, is described. Survival of 94.8 per cent of insects in transit is reported.

Preliminary studies on the association of the Douglas-fir beetle with species of Diptera found in windthrown Douglas-firs were conducted in 1962 and 1963. These studies revealed that larvae of Medetera aldrichii Wheeler preyed upon larvae and pupae bur only rarely on teneral adults of the Douglas-fir beetle whereas larvae of Lonchaea furnissi McAlpine did not kill the bark beetle in any stage. Adults of M. aldrichii lived up to i weeks at 70° F. on granary mites, and L. furnissi adults survived for more than 3 weeks on honey and Metrecal. Seasonal and daily emergence patterns from naturally infested Douglas-firs are presented and the effects of temperature and light on emergence and flight are discussed.

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.

Females of Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae) laid fewer eggs on parasitized than on unparasitized pupae of the house fly, Musca domestica L. Chemical and/or physical conditions of parasitized pupae are detected by the female’s ovipositor, causing this restraint. These conditions may in part result from the host’s death, caused by earlier parasitization, but other factors are also involved. These may include venom injected by the female parasite before she lays, and internal injury to the host resulting from insertion of the parasite’s ovipositor. The female parasite does not discriminate because of physical or chemical traces on the surface of parasitized puparia, of eggs or a surface wound on the pupa, or of absence of heart beat in the pupa.

Predators that have fed on Panonychus ulmi (Koch) and Bryobia arborea Morgan and Anderson can be distinguished by the orange and reddish carotenoid biochromes derived from the prey. Predation on the two species of mites cannot be clearly separated. The predators are squashed on filter paper and the pigments separated by circular chromatography in a mixture of one part of zylene to four parts of white kerosene. The mite pigments are considerably altered during digestion in the predators. The method does not reveal the number of mites consumed by a predator, owing to differences in the pigment content of the various stages of the prey and in the time the pigments are retained in the predators.

In recent years the pine needle miner, Exoteleia pinifoliella (Chamb.), has occurred in large numbers in jack pine plantations in southern Quebec. The female lays its eggs in late June and early July, and larvae, after moulting to the fourth instar, overwinter in the second needle mined. The following spring the larvae continue mining the needles in which they overwintered, moult for a fourth time, and attack a third needle, wherein they pupate. A description of all stages is given, and the habits and controlling factors of the insect are discussed.

The orientation of mature, female Frontinella communis (Hentz.) on horizontal sheet webs was recorded in the field. Spiders fully exposed to direct solar radiation oriented independently of the sun at ambient air temperatures from 18 to 27 °C., but at higher temperatures, corresponding to web temperatures from 30 to 37 °C., they oriented toward the sun's disk in both the horizontal and vertical planes. The orientation of spiders in shade was independent of the sun's azimuth over the entire range of air temperatures experienced (18 to 34 °C). During light to moderate rainfall spiders oriented in the direction of the prevailing wind and the vertical displacement of the body axis from the typically horizontal position varied directly with rainfall intensity.

Tests on adults of the migratory grasshopper, Melanoplus bilituratus (Wlk.), showed carbaryl (1-naphthyl N-methylcarbamate) to have a very marked negative temperature coefficient of toxicity. This was believed to be due to a rapid increase in the rate of detoxification at higher temperatures. The marked synergistic effect of piperonyl butoxide, believed to act by blocking the detoxification process, appeared to confirm this.

Investigations of the bionomics and populations of Cyzenis albicans (Fall.), in relation to its principal host, Operophtera brumata (L.), were carried out during 1962–1963 in two stands of red oak in Nova Scotia. C. albicans was well synchronized with its host and oviposited only on leaves damaged by the host or by other defoliators. C. albicans was found experimentally to develop in larvae of a native species, Operophtera bruceata (Hulst). The distributions per leaf cluster of parasite eggs and host larvae were of the negative binomial type and it sampling technique employing 12 leaf clusters per tree produced standard errors which varied between 18 and 33% of the mean for average densities of 12 to 2 eggs per cluster. Parasite eggs per leaf cluster and percentage parasitism increased as host density increased. An associated defoliator, Pseudexentera cressoniana Clem., because it apparently stimulated parasite oviposition but was not itself susceptible to parasitism, had a detrimental effect on the efficiency of the parasite.

Stained sections of female adult Platypus wilsoni Swaine showed that the punctures concentrated on the caudal half of the pronotum are fungus pits or mycangia. A fungus resembling Tuberculariella sp. was cultured from this area. Mycangia were not found in male adults.