The potential of chlorpyrifos-methyl and Counter® (S-[tert-butylthio) methyl] O, O-diethyl phosphorodithioate) as soil insecticides was assessed in the laboratory. Two established soil insecticides, chlorpyrifos and phorate, which are similar in chemical structure to chlorpyrifos-methyl and Counter respectively were included for comparative purposes. Spectrum of activity was determined using 24–48 h crickets, Acheta pennsylvanicus (Burmeister), 24–48 h adults, Chaetopsis spp., third stage darksided cutworms, Euxoa messoria (Harris), northern corn rootworm adults, Diabrotica longicornis (Say), and honeybees, Apis mellifera L. Chlorpyrifos-methyl and chlorpyrifos showed the broadest spectrum of activity being toxic to all five species of insects; Counter and phorate were toxic to four of the five. Initial activity in soil was assessed relative to soil type, moisture, and temperature using crickets as the indicator species. Chlorpyrifos-methyl was as effective and more consistent in activity than chlorpyrifos. Counter was more effective and consistent in soil than phorate other than under conditions of low soil moisture. No clear relationship between chemical structure and either direct contact or initial toxicity in soil was apparent. Tests on persistence of biological activity in mineral soil indicated that, as is generally the case with dimethyl and diethyl forms of organophosphorus insecticides, chlorpyrifos-methyl was even less persistent than chlorpyrifos. Counter was slightly more persistent than phorate. Although very active the potential of chlorpyrifos-methyl as a soil insecticide would be restricted by its limited persistence. Counter was considered to have good potential.

The influence of temperature on the development of immature stages of Bracon mellitor Say, a braconid parasite of the boll weevil, Anthonomus grandis Boheman, was studied at a series of constant and variable temperatures. Resulting developmental rates and times were compatible with recent advances in the theory of thermal responses exhibited by poikilotherms. Mean development times recorded were in close agreement with predictions calculated from a previously derived absolute reaction rate development model.

Bracon mellitor cohort developmental data were also checked against a prototype stochastic cohort development model. In this comparison, observed and predicted probability distributions agreed for constant and variable day/night temperature regimes but showed some differences under sinusoidal temperature regimes.

Athrycia cinerea (Coq.) is a univoltine parasite of bertha armyworm, Mamestra configurata Wlk., on rapeseed in the Prairie Provinces of Canada. Details of the parasite’s seasonal life history are presented. Females oviposit on third, fourth, fifth, and sixth instars of bertha armyworm, and the parasite larvae usually develop gregariously and mature on the fifth and sixth instars. Supernumerary parasite larvae on superparasitized hosts starve; surviving larvae develop more rapidly, form smaller pupae with a lower capacity for survival, and eventually produce a consistently though not significantly smaller percentage of female adults than parasites that develop on non-superparasitized hosts. Larvae of A. cinerea are often killed if they compete with larvae of Banchus flavescens Cress., the only other common parasite of bertha armyworm, and a small percentage of the pupae of A. cinerea are killed by a hyperparasitic ichneumonid, Phygadeuon subfuscus Cress.

The presence of female-produced sex pheromones in diaspidid scales has been known for several years, and was recently documented for the San Jose scale, Quadraspidiotus perniciosus (Comstock) (Rice 1974). This paper reports the results of 3 years of seasonal monitoring for male San Jose scale in an attempt to determine how and when this pheromone might be used as a monitoring technique in pest management programs in deciduous fruit orchards. These studies were conducted at the San Joaquin Valley Agricultural Research Center near Parlier, Fresno County, Calif.

Annual surveys of the adults show that outbreaks of grasshoppers in cultivated crops in Alberta have occurred in 32 of 58 years. Five outbreaks have occurred, lasting from 3 to 14 years, interspersed by periods of low infestation lasting from 3 to 9 years. Some control measures, however, were required every year even during periods of low infestation. The highest recorded adult populations occurred in 1933, 1936, and 1962, and the lowest in 1952 and 1969.

During most periods with low populations, infestation were confined mainly to the area south of the Bow and South Saskatchewan rivers. When high populations occurred, the infested areas increased in size and extended north to the Battle River. The largest infested area covered 48,600 sq. miles and the smallest was 300 sq. miles.

Two species of grasshoppers, Camnula pellucida (Scudder) and Melanoplus sanguinipes (Fabr.), generally predominated in separate regions. Melanoplus bivittatus (Say) predominated only during periods of low grasshopper infestation. Melanoplus packardii Scudder was restricted in its range and became noticeable when the grasshopper outbreaks were declining.

A sex pheromone was detected in female moths of the beet webworm, Loxostege sticticalis (L.). Laboratory tests with synthetic compounds established that the male moths exhibited sexual responses to E-11-tetradecen-1-yl acetate and they were attracted to this compound in the field. Mixtures of E-11-tetradecen-1-yl acetate containing 5, 10, or 80% of the Z-isomer inhibited the attraction of the male beet webworm moths. Mixtures containing 5 or 10% of the Z-isomer attracted male moths of Lymnaecia phragmitella Stainton (Cosmopterygidae). Male moths of Hysterosia cartwrightana Kearfott (Phaloniidae) were also attracted to E-11-tetradecen-1-yl acetate in traps placed at a height of 0.3 m, with only a few attracted to traps at 1 m as used for the beet webworm.

Preserved material from 1962 field studies provided information on the habits and morphology of the tachinid parasitoid Chaetophlepsis nasellensis Reinhard. Parasitization of the larvae of the western hemlock looper, Lambdina fiscellaria lugubrosa (Hulst), continues over a 30- to 40-day period. Maggots issue from the host larvae and drop to the ground to pupate. The pupae normally overwinter, with adults emerging the following spring or summer. The early first-instar larva differs markedly from the late first-instar. The three instars can be distinguished on the basis of body length and the structure and form of the buccopharyngeal apparatus. The first and third larval instars and the puparium are distinctive enough to permit easy identification during studies of the western hemlock looper and associated loopers.

One female of Eusimulium rendalense Golini and three of E. fallisi Golini, among nearly 470 simuliids captured from Anas boschas L. in Norway, were found naturally infected with mermithid nematodes Two of these infected flies had fully fed on avian blood. The nematodes may be a species of the Gastromermis boophthorae complex Welch and Rubzov.

Hay bales from areas of high skipper densities contained an estimated 5000 viable eggs/bale underlining the importance of passive transport of Thymelicus lineola (Ochs.) eggs in hay as a means of dispersal for this insect pest. While eggs ingested by cows did not survive it is believed that, in view of the number present in each bale, some would not be eaten and could be the source for a new infestation.

Cleared slide mounts of antennae of 30 species of Ptomaphagus beetles showed two internal sensory vesicles in segments 7, 9, and 10. The vesicles were of similar size in each segment except in segment 7 of cavernicolous species. SEM study showed a narrow circular opening in the distal face of segments 7, 9, and 10 which opens into a widened circular canal inside of and under the segment’s distal surface. Sensory vesicles are pockets in the bottom of this canal. The canal and vesicles are predominantly lined with a unique type of fluted sensilla basiconicum. These sensilla are more elongated and more numerous in cavernicolous species. The origin and evolution of the sensilla and vesicles are discussed.

Newly moulted sixth instar larvae of spruce budworm, Choristoneura fumiferana, were force fed graded dosages of preparations containing (1) purified crystals, (2) purified spores, and (3) mg/mg mixtures of purified spores and purified crystals. The LD50 for purified crystals was 0.094 μg/larva and for the mixture 0.096 μg/larva but the latter preparation had an LD50 of 0.048 μg/larva based on crystals indicating that the presence of 2.4 × 105 spores enhanced the toxicity of crystals twofold. The LD50 spore crystal corresponded to LD60 for crystals alone. The LD50 for spores treated with proteinase to remove residual crystals was 20 μg/larva, or 1,0 × 108 spores. The regression coefficients were not significantly different from each other in all three preparations indicating a common or similar mode of action. It is concluded that spores play little or no role in mortality of spruce budworm induced by Bacillus thuringiensis insecticides.

Sexual behavior in the two species of Cysteodemus LeConte consists of: (1) a simple form of courtship that lacks an elaborate tactual display, (2) a prolonged mating period during which the male remains mounted on the female, (3) high levels of female receptivity regardless of previous mating, and (4) postcopulatory behavior. This behavior represents a condition intermediate between that found in the Meloinae and Nemognathinae, the two major subfamilies of blister beetles.

A model for intraspecific competition that incorporates the effects of inter- and intra-stage survival rates, spatial distribution, and variation in growth is developed using basic probability theory. Simulation results for cannibalism in Heliothis zea (Boddie) are presented and intraspecific competition is shown to have effects on population cyclicity and on mortality.

Wasps of the genus Polistes have a number of characteristics that make them particularly suitable for studies on insect social behaviour. The females construct nests with exposed combs, have a reasonably complex social behaviour, and usually lack obvious morphological caste differences. In addition, the adults of many species establish colonies as groups of siblings (foundress associations), a method which is intermediate between colony founding by swarming, and colony founding by individual queens (Wilson 1971). Because of these characteristics, Polistes have been of interest to biologists who are concerned with the evolution of social behaviour in insects (e.g. Alexander 1974, Gibo 1974, Lin and Michener 1972, West 1967, West Eberhard 1969, 1975). Consequently, there is a need for a simple technique for rearing various species of Polistes under controlled conditions. Gibo (1974) briefly described modifications of Gillaspy's (1971) rearing method for P. apachus which made mass rearing of P. fascatus possible. This note describes the modified method in greater detail, and includes improvements that have resulted in increased yield and greater synchrony of colony growth. The improvements have been developed over 3 years and the method has been used to rear more than 100 colonies of various species of Polistes, including P. fuscatus, P. apachus, and P. dorsalis.

When different size sticky-coated red spheres were positioned within the foliage canopy of sour cherry or apple trees, more Rhagoletis pomonella (Walsh) flies were always captured on 7.5-cm-diam. ones than on 3.4 or 1.5 cm ones. Early in the season, 7.5 cm spheres attracted fewer or about as many R. pomonella as 23 cm spheres, but later on, 7.5 cm spheres always attracted more. R. fausta (Osten Sacken) and R. cingulata (Loew) flies were always more attracted to 7.5 cm spheres than to any other size tested. However, both these species showed a proportionately greater attraction to smaller spheres than did R. pomonella. The phenomena of super-normal stimuli and learning are proposed as possible explanations of certain of these findings.

Sampling techniques for estimating egg populations of the clover root curculio, Sitona hispidula (F.), were developed in alfalfa and red clover fields in Kentucky. An appropriate sample unit was a 3 × 3 in. (7.6 × 7.6 cm) area of plants and the soil beneath it to a depth of 4–5 in. (10.2–12.7 cm). This was processed by a flotation technique. The spatial disposition of the eggs conformed to a clumped pattern in both fields. The variation of 88 to 93% in log variances was accounted for by the variation in log means. There were no significant differences in dispersion pattern between the two crops. Variance analysis revealed that block and plot differences were rarely significant but the interquadrat variance predominated. The number of samples required to estimate the population with specified level of significance and margin of error was inversely proportional to population density.

Formation of cocoons by larval Chironomidae has been reported in Endochironomus spp. (Sæther 1962), Hydrobaenus pilipes (Malloch) (as Trissocladius pilipes) (Hudson 1971), and Parakiefferiella sp. (Hudson 197 1). This is the first report of larval cocoons formed by a species of Eukiefferiella.

Plants of the genus Taxus have pharmacologically active materials that elicit hypotensive effects and act on the cardiovascular musculature of dogs (Bourbeau 1954; Duval, unpub. data, 1974). Extracts from Taxus canadensis (Marsh) are more potent than those from T. baccata L. (Vohora 1972). In an investigation of Canadian plants for insecticidal and pharmacological activities, we observed that no insects fed on plants of the genus Taxus. Therefore we tested the toxicity of aqueous extracts of T. canadensis on two species of insects, Macrosiphum euphorbiae (Thomas) (Homoptera: Aphididae) and Tribolium confusum Duval (Coleoptera: Tenebrionidae).

There was no evidence that the corn leaf aphid, Rhopalosiphum maidis (Fitch), can overwinter in southwestern Ontario. An alate with a small colony of nymphs was found on 26 April, indicating that migration from the south starts early in the spring. Early migrants colonized winter barley, but not winter oats, rye, or wheat. Colonization on field corn did not occur until over a month after plant emergence. Only small numbers of alatae initiated infestations on corn and the large variation in size of aphid infestations observed at pollination was due to differences in the longevity and fecundity of these few early attackers. The whorl leaves which enclosed the tassel before pollination provided a very favorable environment for rapid development of the aphids. Trapping of alatae in yellow pans of water at the periphery of a corn field in the fall showed that a minimum temperature of 13°C was required for flight. At a constant temperature of 25.5°C and a light:dark photoperiod of 14:10 h, the average prereproductive, reproductive, and postreproductive periods for 29 aphids were 5.9, 15.8, and 9.6 days, respectively. The average number of nymphs produced/female was 68.2.

The new species of Elatophilus described herein was in the Anthocoridae collection of the late Mr. J. F. Brimley, Wellington, Ont. This collection of Hemiptera and Coleoptera was recently bequeathed to the Canadian National Collection of Insects, Ottawa.