A temporary pond close to Calgary, Alberta, was studied for 2 years. In the spring of the first year (1974) the pond filled with water to a much higher level than normal and it did not dry and reflood until August. The first flooding hatched eggs of Aedes euedes, A. cataphylla, A. excrucians, A. fitchii, A. flavescens, and A. mercurator; the second flooding hatched eggs of A. vexans and A. cinereus. Estimates of larval population size were made for the latter two species and little larval mortality occurred until the pond was reduced to a few small puddles, when larvae became stranded. The pond dried completely before the pupal stage was attained. Fifty per cent of surviving A. vexans larvae attained instar II in 3.7 days, instar III in 6.6 days, and instar IV in 10.3 days. A. cinereus developed more slowly.

In the second year (1975) the pond contained water from the middle of April to the beginning of June, and did not refill in the summer. Estimates of larval population sizes were made for A. euedes and A. mercurator. These larvae shared a preference for the deeper water in the centre of the pond. Their numbers declined at rates of 9% per day for A. euedes and 7% per day for A. mercurator. Larvae in the second instar survived a period of 3 days when the water surface was covered with ice and snow, but A. euedes experienced a sharp drop in numbers at this time.

Fifty-three per cent of the eggs of A. vexans survived a period of 1 year in areas not flooded with water at appropriate temperatures for hatching.

The effect of an alternating and a constant temperature regime on some aspects of the biology of two strains of Hylemya antiqua were studied. One strain was a laboratory strain, the other a newly colonized wild strain. Several population statistics were assessed and life tables constructed. Significant differences between the strains were recorded.

The laboratory strain mated significantly better under both environments than the wild strain, it also oviposited earlier and lived longer. No difference between the strains was recorded for either total egg production or oviposition rate. The wild strain larvae survived significantly better than the laboratory strain larvae and produced larger pupae. As the weighted mean temperature of the alternating regime was 16.6°C compared with the constant regime of 23°C many temperature dependent processes were retarded. Nevertheless as the alternating temperature increased larval survival and increased pupal size, this temperature regime has now been adopted for the routine laboratory rearing of H. antiqua larvae. The net reproductive rate, R0, and the intrinsic rate of increase, r, were calculated for both strains in both environments. The wild flies had the highest R0 at the alternating temperature and the lowest at the constant temperature. This trend was completely reversed when r was calculated as this statistic takes into account generation time, which was much shorter in the constant temperature.

The results were discussed in the framework of the quality of the laboratory stock in relation to its use in a genetic control programme.

Aleochara bipustulata (L., 1761) (Coleoptera: Staphylinidae) is a Palearctic species and a natural enemy of the cabbage root maggot, Delia radicum (L., 1758) (Diptera: Anthomyiidae). It has been identified as a candidate for introduction to Canada for classical biological control of D. radicum. Recent taxonomic studies assert that A. bipustulata is absent from the Nearctic; however, there are numerous publications reporting the presence of the species in North America. We examined voucher material relating to these publications and additional museum specimens labeled as A. bipustulata. In addition, we reared Aleochara spp. from D. radicum puparia collected in the Canadian prairie provinces. Specimens that, based on external anatomy, could be A. bipustulata were definitively identified using characters of the genitalia. All of the 141 museum specimens labeled A. bipustulata were found to be Aleochara verna Say, 1836. A total of 811 individuals of Aleochara spp. were reared from D. radicum puparia; of these, 690 were Aleochara bilineata Gyllenhal, 1810, 121 were A. verna, and none were A. bipustulata. We have found no evidence that A. bipustulata occurs in North America.

A Latin square design field experiment using treatment, site, and occasion as main effects was set up in spring 1981 to assess the responses of Trypodendron lineatum (Olivier) and Gnathotrichus sulcatus (LeConte) to traps baited with the pheromones lineatin and sulcatol alone and in combination with each other and with ethanol plus α-pinene. Addition of sulcatol to either lineatin or lineatin plus ethanol plus α-pinene resulted in significantly reduced catches of T. lineatum. Addition of ethanol plus α-pinene to sulcatol or lineatin resulted in significantly greater catches of both sexes of G. sulcatus and T. lineatum. These results suggest that separate traps be set out for each species in mass trapping suppression programs in timber processing areas and that ethanol and α-pinene be included with the pheromone to maximize catches of both of these ambrosia beetle species.

Sequential sampling methods have been developed for population surveys of a number of forest insects (4, 6, 7, 9). These methods permit rapid classification of populations into broad infestation classes with predetermined accuracy and a minimum of sampling, and are useful for mapping and recording widespread infestations.

The method of assessing egg populations of the larch sawfly, Pristiphora erichsonii (Htg.), developed by Ives (3) for intensive population studies, was not suitable for surveys because of the large sample size required. A sequential plan for the larch sawfly using hypothetical infestation classes was briefly reviewed by Ives (2). This plan is modified in the present paper in accordance with new data that have accumulated from observations on plots in the Whiteshell Forest Reserve and other stands in Manitoba and Saskatchewan.

In the present study, effects of body size and prey quality on reproductive attributes and longevity of two aphidophagous Coccinellidae (Coleoptera), Coccinella septempunctata (Linnaeus) and Coccinella transversalis Fabricius, have been investigated in laboratory conditions. Higher fecundity, egg fertility, and longevity were obtained in larger females of C. septempunctata on pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), and in C. transversalis on bean aphid, Aphis craccivora Koch (Hemiptera: Aphididae). Males of C. septempunctata survived longer than those of C. transversalis on both prey. Number of clutches was lower and clutch size was higher in early and late reproductive phase; the reverse was observed in the middle of the reproductive phase. Larger females of C. septempunctata and C. transversalis laid higher number of clutches than the smaller ones. Thus, both body size and prey quality affect reproductive performance in Coccinellidae, though size variation did not change the prey preference.

General.—The purpose of this paper is to analyse a sampling method devised to assess larval populations in an outbreak of the lodgepole needle miner, Recurvaria milleri Busck (Busck 1914, Hopping 1945).

The problem of developing an adequate sampling method is intimately concerned with the life-history of the insect, the region of the outbreak and the nature of the forest stand in which the outbreak occurs. In sampling most defoliator populations the problem is made more difficult by external feeding and wandering habits, hence it is usually done in some relatively inactive stage at a fixed time. de Gryse (1934) describes the problems inherent in sampling these insects. The needle miner, however, is fixed in its location for most of its life-cycle and is therefore readily obtainable for study. The problem here is reduced to a statistical one, that of obtaining an acceptable sample i.e. within suitable error limits with due regard for existing variables.

The genus Carphacis des Gozis (Staphylinidae: Tachyporinae) is revised and recognized as a valid genus rather than a subgenus of Lordithon Thomson (= Bolitobius auctorum). Three species, dimidiatus Erichson, intrusus Horn, and nepigonensis Bernhauer are recognized as valid and transferred from Lordithon to Carphacis. Bolitobius dimidiatus humeralis Melsheimer is considered a new synonym of C. dimidiatus, and B. ruber Malkin and B. intrusus wallisi Malkin are considered new synonyms of C. nepigonensis. All taxa are described and illustrated and maps showing the known distribution of each species are included. A key is presented to aid in distinguishing the North American and only known Palearctic species.

Data on the distribution of overwintering jack pine budworm (Choristoneura pinus pinus Free.) collected between 1985 and 1987 in northern Ontario are used to develop guidelines for sampling this stage of the budworm. Two alternative methods of expressing budworm density are considered: counting the number of budworms per metre of branch and counting the number per square metre of branch bark surface area. Estimates of budworm density for three levels in the tree’s crown are given for 4 site-years.

Entire branches are recommended as the sample units as the use of 60-cm branch-tip sections resulted in consistent underestimation of actual density per branch. Jack pine budworm density did not vary among cardinal compass directions and was generally highest at mid-crown levels.

The distributions of two parasitoids, Apanteles fumiferanae Vier. and Glypta fumiferanae (Vier.), which overwinter as an egg or first-instar larva within the jack pine budworm, also were considered. Apanteles was the most abundant parasitoid at all crown levels at all sites examined. Percentage parasitism by Apanteles was highest and that by Glypta was lowest on the branch-tip sections in relation to the branch-basal section, but total percentage parasitism was relatively constant over the entire branch, throughout the tree crown, and from tree to tree. Consequently, the sampling method for jack pine budworm is easily extended for estimating the rate of parasitism and therefore for providing a prediction of mortality that results from these two common parasitoids.

The Douglas-fir cone moth has been reported causing damage to cones and seeds of Douglas fir for a number of years; reports of seed loss range from light to almost 100 per cent. The insect occurs throughout the range of the host in British Columbia, the Pacific Coast States, and the Rocky Mountains.

Observations recorded here were made during 1957 and 1958 in the Cowichan Lake area of Vancouver Island, and 1959 in the interior of British Columbia.

All known bird fleas are believed to have been derived from species that originally infested mammals. Circumstances evidently have occurred whereby representatives of species that were ordinarily the parasites of mammals became associated with buds, and were successful in establishing themselves on these hosts. These circumstances must have included some provision for isolation whereby the newly transferred colonies of fleas were not given the opportunity of becoming reassociated with the original hosts, and also were not contaminated by subsequent introductions of others of their species. Thus they were able to become adapted to an existence on the bodies and in the nests of avian hosts. The adaptations were physical as well as physiological, many bird fleas exhibiting morphological characteristics which, though not yet properly understood, apparently bear some relationship to their specialized environment.

The larval morphology of the dytiscid genus Oreodytes Seidlitz was investigated through a detailed analysis of 16 Nearctic and two Palearctic species. Many structural features, especially those of chaetotaxy and porotaxy of head capsule, head appendages, legs, last abdominal segment, and urogomphi, were found to be useful for taxonomic and phylogenetic comparisons. Within the tribe Hydroporini, it is proposed that Oreodytes shares a monophyletic origin with the genera Deronectes Sharp, Scarodytes Gozis, Nebrioporus Régimbart, and Stictotarsus Zimmermann. A tentative phylogenetic reconstruction of the genus Oreodytes, based on 29 larval characteristics, is provided. The classification of members of Oreodytes indicated by larvae is shown to be only partly reconcilable with the one indicated by adults. Once subdivided into three species-groups, Oreodytes now comprises four species-groups: the O. picturatus, O. obesus, O. scitulus, and O. quadrimaculatus species-groups. Oreodytes quadrimaculatus was found to share a monophyletic origin with the members of the O. picturatus and O. scitulus species-groups. The taxonomic status of the genus-name Neonectes J. Balfour-Browne is reconsidered as the larvae of N. natrix (Sharp) and N. babai Satô are revealed to be most similar morphologically to members of the O. scitulus species-group.

The successful flight takeoff of untethered Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), consists of a strongly sequenced set of behaviors beginning with site location and followed by expansion of the hind wings, rising of the mesothoracic legs, air lifting, and rising of the prothoracic legs, leading to a low angle flight departure. A series of ablation experiments demonstrated that the antennae, the elytra, the mesothoracic legs, and the prothoracic legs all play a significant role in determining the percentage of successful flight takeoffs, as well as the proportion of upward versus downward liftoffs. Flight takeoff of tethered L. decemlineata is positively stimulated by head winds of increasing speeds up to speeds of slightly more than 5.5 m/s. The absence of tarsal contact does not stimulate flight takeoff in L. decemlineata, but tarsal contact interrupts flight. The flight characteristics during liftoff indicate that this species is an in-phase functionally four-winged insect, probably with the hind pair of wings leading the wing beat. Among Coleoptera, the takeoff of L. decemlineata was found to belong to the Melolontha type (classification of Schneider 1975), because the elytra are active.

The previously undescribed adult male and female of Analetris eximia Edmunds are treated. Additional features of nymphs are illustrated. In the Saskatchewan River system the species is found in areas unaffected by reservoirs; nymphs develop in May?, June, and July; adults emerge in late July. Nymphs are carnivorous (chironomids were the main food item in field collected specimens), live in backwaters adjacent to the main river current, and are morphologically adapted to life on an unstable silty substrate. Invasion of the Saskatchewan system was apparently via Missouri tributaries from the Colorado system. It occurred in recent times in the latter but apparently not the former. Because of habitat destruction, the species is considered endangered.

We studied the effects of inundative releases of the egg parasitoid Trichogramma minutum Riley (Hymenoptera: Trichogrammatidae) on economic injury by grape berry moth, Endopiza viteana (Clemens) (Lepidoptera: Tortricidae). Trichogramma minutum originally collected from natural host populations near North East, Pennsylvania, was mass produced in tobacco hornworm hosts and Mediterranean flour moth. We released T. minutum in border rows, where grape berry moth infestation is typically high, of experiment field station and commercial vineyards from 1996 to 1999. We recorded significant reductions in economic injury in plots where parasitoids were released. In vineyards with low to moderate grape berry moth abundance, four releases during the growing season were adequate in reducing damage at harvest to below 3%. In high-risk vineyards, T. minutum releases reduced damage to levels below 15%. The use of buckwheat as a cover crop to provide nectar in combination with parasitoid releases showed potential benefits in parasitoid activity. A biocarrier and Biosprayer™ were used in mechanized parasitoid-release operations, and no adverse effect on parasitoid emergence was recorded from parasitized eggs using this approach.

The pea aphid parasite Aphidius smithi Sharma & Subba Rao has four larval instars. The first and the fourth instars are mandibulate. The second instar possesses oral lobes but not mandibles. A bilobed feeding structure on the ventral side of the head of the third instar could function as a pharyngeal pump. The chief diagnostic features of each instar are illustrated with scanning electron micrographs. Variability in the number of larval instars among species of Aphidiidae is discussed.

Five species of parasites reared from European material were released at Oak Hill, near Bridgewater, Nova Scotia from 1954 to 1956 as biotic agents against the winter moth, Operophtera brumata (L.) which had been established in Nova Scotia since before 1950. Recovery collections were made annually from 1955 to 1957. This work is still in progress, and in 1957 releases were made in four additional localities. Results of establishment of parasites from releases from 1954 to 1956 are reported below.

A non-pest population of Colorado potato beetle, Leptinotarsa decemlineata (Say), was monitored in the field and in the laboratory to define some cultural and host plant factors that might prompt increased use of potato by a population locally adapted to a wild host species (Solanum sarrachoides Sendt.). This study tested whether elimination of the beetle’s natural host from plots of potato would result in increased densities of beetles on potato, and examined whether beetles showed differences in performance on and in preference for S. sarrachoides or potato. In 2 years of study, egg densities on potato were higher in weed-free than weedy plots; paired preference tests in the laboratory also indicated that beetles deposited the most egg masses (92%) on S. sarrachoides. Densities of larvae and adults on potato were not affected by weed density. Growth rates of larvae were significantly faster on S. sarrachoides than on potato for both early-season (pre 7 July) and late-season (post 21 July) foliage. Survival and adult size were not affected by host species. In choice tests, late-instar larvae preferred S. sarrachoides to potato. Host preference of larvae varied with age of foliage, and S. sarrachoides became increasingly preferred later in the growing season.

We conducted laboratory experiments assessing the relationship between commercial greenhouse polyethylene coverings and bumble bee, Bombus impatiens Cresson (Hymenoptera: Apidae), activity and loss from ventilation systems. Bee activity was measured in four small greenhouses, each with a different polyethylene covering. Bee activity was quantified using photodiode tunnels mounted in the hive entrances. Contrary to commercial greenhouse experiments, there was no difference in bee activity based on covering type. There was a positive linear relationship between temperature in the experimental greenhouses and bee activity. The potential for bee loss through open ventilation systems for five covering types was quantified using a Y-maze decision box. Bees were more attracted to direct light than to light transmitted through ultraviolet (UV) blocking coverings, whereas bees were equally attracted to direct light as they were to UV-transmitting coverings. These experiments suggest that greenhouses with UV-transmitting plastics may result in less bee loss through ventilation systems.

Atmospheric convection is a process which involves the more or less vertical motion of air currents. During the discussion of winds (Part II), the writer indicated that winged insects inactivated by low temperatures, or wingless insects within any temperature zone, required vertical currents for support, and for assistance in horizontal transport, rather than horizontal currents alone, regardless of the strength of the latter currents. In the following pages, the process known as thermal convection will be considered as a means for the vertical and horizontal distribution of insects.