Tests of intertrap variability in catches of moths of the darksided and redbacked cutworms, Euxoa messoria (Harris) and E. ochrogaster (Guenée), were conducted by placing two traps for each species baited with synthetic sex attractants at 1.6 km (1 mi) intervals to form a grid covering 64 km2 (25 mi2) near Domain, Manitoba. These sex attractants were 93 and 99.6% species specific for E. messoria and E. ochrogaster respectively. Moth catches varied between traps and flights, but the ranking of the traps by catch for each species was consistent during any given flight period. Variability in intertrap catches of E. messoria indicated the moths were not evenly distributed throughout the test area and consequently a sex-attractant trap system with 1.6 km trap spacing is not suitable for monitoring population levels. For E. ochrogaster four traps within an area of 64 km2 would be required to give a population estimate within 20% of the true mean. The flights of E. messoria are not related to degree days and started abruptly and at the same time each year suggesting that development may be synchronized by the summer diapause of the prepupae. The flights of E. ochrogaster were related to degree day accumulations above a threshold temperature of 12.5 °C. Crops had no apparent influence on the distribution of moth catches for either species.

Frontalin, seudenol, and a spruce terpene blend are key components of a lure for monitoring spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae: Scolytinae) in eastern Canada, catching the highest number of beetles in several field trials. The standard two-component commercial lure for this species, developed from populations in western North America and composed of 95%:5% (±)-α-pinene and frontalin, failed to elicit attraction to traps in Atlantic Canada; thus a series of trapping experiments were conducted to identify an improved combination of pheromone and host volatiles for this region. Analysis of volatiles from D. rufipennis collected from Newfoundland and Nova Scotia, Canada detected seudenol as an additional female-produced component. Laboratory analysis of the eastern host (Picea glauca (Moench) Voss; Pinaceae) detected the presence of 75%:25% (±)-α-pinene; however, a two-component lure comprised of 75%:25% (±)-α-pinene and frontalin caught no more beetles than an unbaited control. Frontalin and seudenol alone or spruce terpene blend and ethanol alone typically had among the lowest trap catches, but when combined they caught the highest numbers of D. rufipennis, supporting the hypothesis that host volatiles synergise attraction to pheromones. Our results highlight the importance of geographic variation in the response to pheromones and kairomones in this bark beetle.

The plum curculio (PC), Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae), is a key pest of stone and pome fruit in North America. Though grandisoic acid (GA) was identified as a male-produced aggregation pheromone for this species, other components likely exist, as have been identified for various curculionids. To better determine these components, an understanding of the conditions necessary for optimum pheromone production and attraction is needed, this is essential for the improvement of monitoring techniques and to achieve better biological control. The goal of this study was to determine the biotic and abiotic factors influencing both the response to pheromones and pheromone production. Tests were conducted in a dual-choice still-air vertical olfactometer using live male PCs as odour sources and live females as responders, to determine which physiological factors (age, number of males, mating status) influenced female response to males. Head-space collections of GA production under various conditions (airflow rate and frequency, collection zone strata, variation of humidity, temperature, and presence of a harbourage) were also done, as were electroantennograms (EAG) using synthetic pheromone mixtures. Results revealed that for both strains, the odour of two virgin mature males elicited significantly greater and more consistent attraction from mature virgin females than other ages and numbers of males when compared with the control. Head-space collections indicate that male PC have increased production of GA under high humidity in the presence of fruit, indicating that these conditions are necessary for optimal pheromone production and collection. EAG studies revealed significant responses to GrandLures I, II, III/IV and to the positive enantiomer of GA, and the amplitude of the signal varied with concentration. Our data identify the optimal physiological state and conditions at which pheromone collections should be performed, and what physiological life stages respond to these stimuli. These results have implications for optimising monitoring tools for this serious crop pest. This species has a northern univoltine strain and a southern multivoltine strain, both of which were examined in this study.

Section 7 of the primary simplex of the ductus ejaculatorius of unmated male spruce bud worm moths, Choristoneura fumiferana, contains a yellow substance that is not present in recently mated males. The yellow substance occurs in laboratory-colony males reared on diet and in feral males reared on foliage. It is shown that the presence/absence of this material is a reliable index of copulation during the previous 24 h. Although the yellow substance regenerates over a period of several days, males 0–72 h post-copulation may be indexed when compared with unmated males of similar age.

The cynipid Diplolepis triforma Shorthouse and Ritchie induces a fusiform, multi chambered stem gall from leaf buds on Rosa acicularis Lindl. in central and western Canada. Galls at all stages of development were fixed and sectioned using botanical histological techniques to illustrate, for the first time, the unique host-modifying abilities of gall-inducing cynipids that distinguish them from other phytophagous insects. Key events in gall ontogeny, whereby D. triforma gains control and redirects the development of attacked host tissues to provide larvae with shelter and food, include proliferation of cytoplasmically dense parenchymatous cells within the strands of the procambium at the point of egg contact, appearance of nutritive cells when larvae first begin to feed, formation of new xylem and phloem extending from un affected vascular bundles to the larval chambers, formation of several layers of nutritive cells during the period of larval feeding, and formation of sclerenchyma cells around each larval chamber. The role of these tissues in galler biology is explained.

Adult corn rootworm beetles, Diabrotica virgifera virgifera LeConte, were maintained at five fluctuating temperature regimens with daily average temperatures of 16.0, 19.5, 23.0, 26.5, and 30.0°C. The mean number of eggs laid per female was greatest (602) at 26.5°C and least (295) at 16.0°C. The median length of life decreased with increasing temperature from 13.8 weeks at 19.5°C to 7.9 weeks at 30.0°C. Parameters were estimated for nonlinear functions relating age-specific fecundity and age-specific survival to physiological age.

The weevils Hylobius radicis Buchanan and Hylobius pales (Herbst) survived to adulthood more frequently, developed more rapidly, and weighed more as adults when reared on diet containing ground phloem from Scots pine, Pinus sylvestris L., or red pine, Pinus resinosa Aiton, than from jack pine, Pinus banksiana Lamb., or eastern white pine, Pinus strobus L. In feeding tests, both weevils preferred Scots pine, although jack pine was preferred over red and white pine. When reared on diets containing phloem from red pines which had received various amounts of nitrogenous fertilizer, H. radicis and H. pales performed significantly better at elevated concentrations of nitrogen. Hylobius radicis adults exhibited a feeding preference for twigs from red pines containing elevated nitrogen concentrations.

The present paper is the second of a series arising from a continuing study of the balsam woolly aphid, Adelges piceae (Ratz.), and its biological control. The history of this introduced insect has been described (Balch, 1952). During the course of our studies a number of records of species associated with A. piceae have been obtained.

While continuing work on a systematic revision of North American mites of the family Blattisocidae (= Aceosejidae), I have received from Mr. R. S. Soper, Jr., females of an undescribed species of mite with singular morphological attributes and an unusual association with an insect host. This species is given separate preliminary treatment in order to permit reference to it in ecological studies by Soper and Olson (in preparation).

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), causes severe damages in strawberry (Fragaria × ananassa Duchesne ex Rozier; Rosaceae) fields in Québec, Canada. Currently, only chemical insecticides successfully control that major pest. Lygus lineolaris aggregate in trap crops such as buckwheat (Fagopyrum esculentum Moench; Polygonaceae) and white mustard (Sinapis alba Linnaeus; Brassicaceae) but do not remain long enough on these plants to significantly reduce damages on strawberries. However, the attractiveness of the trap crop gives the opportunity to gather L. lineolaris in an area of the field where chemical treatments could be applied more efficiently. The aim of this study was to test the effectiveness of the combination of trap crop (buckwheat and white mustard) and chemical treatments to control L. lineolaris. Randomised complete-block design included treatment with either no trap crop, buckwheat, or white mustard row planted close to strawberry plants. Half blocks were treated with insecticide (cypermethrin) sprayed on strawberry plants (in treatment without trap crop) or directly on trap crop. We found that L. lineolaris was more abundant on buckwheat than on white mustard or strawberry plants. Insecticide application on trap crops reduced the population on these hosts, but did not reduce L. lineolaris on adjacent strawberry plants. Behavioural avoidance and physiological pesticide resistance could explain this result.

We studied the dropping behaviour of the foxglove aphid, Aulacorthum solani (Kaltenbach) (Hemiptera: Aphididae), in response to disturbance by the parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae). We banded plant stems with sticky tape to prevent aphids from returning to the plants to determine if these would serve as an integrated pest management strategy for A. solani. Stem banding prevented A. solani that had dropped from returning to the plant; but the mortality associated with banding was not necessarily complementary to biological control by A. ervi. Up to 80% of aphids dropped in response to foraging by A. ervi, and thus could be killed on sticky stem bands. The fraction of aphids that dropped to the ground also contained as much as 90% of the parasitoid's offspring. Overall, mortality of aphids on sticky stem bands was not compatible with parasitoids. Although numbers of aphids declined more rapidly in the first 2 weeks of the trial in the presence of stem bands and parasitoids than in the presence of parasitoids alone, the numbers of aphids were identical in the two treatments from the 3rd week onward. Mortality on the stem bands replaced mortality from parasitoids, and reduced recruitment of parasitoids.

The effects of sprays of DDT, azinphos-methyl, and Ryania applied to a pear orchard on population densities of insect predators of Psylla pyricola Förster were assessed. The P. pyricola in the orchard were naturally tolerant to DDT and Ryania and highly resistant to azinphos-methyl. DDT eliminated or severely reduced numbers of Deraeocoris brevis piceatus Knight, D. fasciolus Knight, Diaphnocoris provancheri (Burque), and Campylomma verbasci (Meyer). Chrysopa carnea Stephens and C. oculata Say were moderately reduced. Anthocoris antevolens (White) and A. melanocerus Reuter were highly tolerant to DDT. Azinphos-methyl severely reduced numbers of A. antevolens, A. melanocerus, C. verbasci, and D. provancheri. C. carnea and C. oculata were moderately reduced. D. brevis piceatus and D. fasciolus were tolerant to azinphos-methyl. Ryania severely reduced numbers of A. antevolens, A. melanocerus, and C. verbasci; moderately reduced D. provancheri; and did not affect D. brevis piceatus, D. fasciolus, C. carnea, or C. oculata.

In the DDT-treated plots the relative densities of Anthocoris spp. approximately doubled compared with the untreated plots. This was probably due to removal of competition for food by other predator species. Large increases ill the relative densities of Deraeocoris spp. were also observed in the Ryania treatments, probably for similar reasons. Significant increases in the P. pyricola populations in response to removal of predation pressure by the insecticide treatments occurred in the DDT and azinphos-methyl plots bur not in the Ryania plots.

Structures of the female genitalia of four species in the genus Cicindela are described and illustrated, and their taxonomic importance is discussed. The presence of a spermatophore in C. flavopunctata is discussed.

The efficacies of registered and unregistered foliar sprays against the tuber flea beetle, Epitrix tuberis Gentner, were compared in 1987, 1988, and 1989 at Abbotsford, B.C. Beetles were released serially in treatment plots and visually counted after each release to determine the effectiveness and longevity of residual control. In 1989, emergence cages placed over previously treated plants measured the effect of sprays on the next generation of beetles. Pyrethroids generally resulted in beetle mortality for longer periods of time than did the nonpyrethroids carbaryl, endosulfan, chlorpyrifos, and methamidophos. Several pyrethroids provided residual beetle control for up to 7 days after application. In 1989, bifenthrin, cyfluthrin, cypermethrin, and deltamethrin were as effective in suppressing emergence of the next generation of beetles as was granular phorate applied at seeding. These studies demonstrated that foliar sprays can be a key component of E. tuberis management programs, especially those operating on soil types where the use of granular insecticides is restricted.

Regression coefficients derived from the Nicholson–Bailey parasite mode) by Hassell and Huffaker (1969) are interpreted, and their conclusions about the biological significance of changes in slope are shown to be invalid. It is demonstrated that the term "delayed density-dependence" has no functional significance because it includes density responses that range from inverse to direct, depending upon the particular theoretical model that is selected for simulation exercises. In natural populations of a number of forest insects, the net response of parasitism to host density is direct, not inverse.

Intra- and inter-crown distribution of eastern spruce gall adelgid, Adelges abietis (L.) (Homoptera: Adelgidae), on young white spruce, Picea glauca (Moench) Voss., was studied at three sites in New Brunswick, Canada. Within a branch, the majority of galls were found on lateral shoots. Similar distributions of galls within trees were observed regardless of whether 20 or 30 lateral shoots or all shoots on a branch were sampled. Gall densities were highest on mid-crown branches of open-grown trees 1–4 m tall and were not influenced by cardinal direction. After crown closure, most galls were found in the upper crown, above the point of branch overlap. In all circumstances, gall distributions were strongly clumped within trees. Inter-tree distribution of A. abietis galls differed significantly from a Poisson but not a negative binomial distribution, indicating a high degree of aggregation among trees. Therefore, a stratified random sampling plan using 20 lateral shoots of a mid-crown branch as a sampling unit would be adequate for monitoring A. abietis populations. If the mid-crown branches are undergoing crown closure, we suggest sampling in the lowest open-grown branch above the point of crown overlap.

1927–Needham – Ann. Ent. Soc. Amer., 20: 108.

1935–Traver – Biol. Mayflies, 565 (hecuba group).

1954–Edmunds and Traver – Proc. Ent. Soc. Wash., 56: 238.

1954– Demoulin – Bull. Ann. Soc. Ent. Belg., 90: 324.

The subgenus Timpanoga of the genus Ephemerella contains but a singIe species,Ephmerella hecuba Eaton. Needham (1927) derived the name for this subgenus from Mt. Timpanogos in north central Utah, after collecting specimens of Ephemerella hecuba in the nearby Provo River. He based the subgenus on the nymph which shows remarkable morphological distinction with its broad entire frontal shelf and its extremely flattened body.

The following synoptic revision of the family Cheliferidae is presented at this time in order to render available for routine systematic use the expanded classification of this important family necessitated by recent morphological and systematic research. It follows along the lines already laid down by the author in previous papers on the higher classification of the Chelonethida as a whole (Chamberlin, 1939, 1930 and 1931) and differs only in the fact that consideration of included species is omitted in all but a few special cases.

Cone-infesting insects have been recognized for many years but have not attracted as much attention as some of the defoliating species. The apparent lack , of interest is quite understandable since seed destroying insects are seldom, if ever, a problem in natural reproduction. White spruce successfully reproduces, despite the numerous insects which are known to feed on the seeds. However, the increased interest in reforestation necessitates the collection of cones and extraction of the seed to supply the demands of forest nurseries. During heavy cone-crop years, enough seed must be extracted and stored to provide a supply for the years when cones are scarce. As all conifers generally produce anabundance of cones the same year, the number of bushels which may be processed for any one species is limited. As a consequence, cone-infesting insects have become a factor of considerable importance.

Water-stress in young apple trees potted in sandy soil caused a six-fold retardation in Panonychus ulmi (Koch) population growth during two generations in a greenhouse. A considerably smaller retardation effect on the population growth occurred on water-stress trees growing in a compost-sand soil mixture. The leaves from moist compost-sand soil trees contained nearly the same percentage of nitrogen as those from water-stress trees, thus it is believed the detrimental effect of water-stress is caused by the inability of the mites to secure sufficient food supplies for maximum reproduction and growth.