As part of a St. Louis Encephalitis Surveillance Program adult mosquitoes were collected weekly from May to September, 1976–1978 with dry ice-baited traps at 11 sites in four areas of southwestern Ontario. Thirty-four species from six genera were caught but of the 210,000 mosquitoes collected, three species, Mansonia perturbans (Walker), Aedes vexans (Meigen), and Culex pipiens Linnaeus (including C. restuans Theobald) comprised more than 90% of the catch. The greatest number of species were collected in June and July. The greatest number of mosquitoes were captured in July as the three principal species were most abundant at this time. The seasonal distributions of the nine most common species are presented and explanations suggested for the patterns of some of these. This study confirms and extends the findings of previous mosquito surveys in southwestern Ontario and should provide useful information for future programs on mosquito research and control in this region. Based on its seasonal pattern, relative abundance, SLE virus isolations and its record as an efficient vector in the USA, C. pipiens is probably an important vector of SLE in southwestern Ontario.

Prepupae of three species of Diplolepis (D. nebulosa (Bassett) a leaf-gall-former, an undescribed stem-gall-former, and D. radicum (Osten Sacken), a root-gall-former) were overwintered at various heights above the ground. Most prepupae of all three species buried beneath the snow survived the winter, while only stem-gall-formers survived at a height subject to fluctuating snow depths. All specimens of the three species that overwintered above the snow were killed.

Eight new genera, seven Nearctic and one Holarctic, are described in the subfamily Sciophilinae. These genera, and their type-species, are: Loicia (L. basifurca n. sp.), Acadia (A. polypori n. sp.), Acomoptera (Eudicrana plexipus Garrett), Adicroneura (A. biocellata n. sp.), Aglaomyia (A. gatineau n. sp.), Drepanocerus (D. ensifer n. sp.), Garrettella (Leia shermani Garrett), Saigusaia (Boletina cincta Johannsen). Sixteen other new combinations and two new synonyms, mostly for species described by Garrett and Sherman, are proposed.

The calling behavior of females of three interfertile sibling species of Euxoa was studied in the laboratory at 20°, 15°, 10°, and 5 °C. At 20 °C the calling posture of E. campestris and E. rockburnei differs from that of E. declarata. However, with decreasing temperatures the calling posture of both campestris and rockburnei becomes indistinguishable from that of declarata. The pattern and duration of calling bouts was similar in all three species and at all four temperatures. Calling occurred progressively earlier in scotophase as temperature decreased but temporal separation between the calling periods of the three species is maintained at all temperatures above the threshold for mating activity. This confirms that temporal separation of mating persists over the range of temperature normally encountered in nature and strengthens the evidence that species-specific rhythms of mating activity are largely responsible for maintaining reproductive isolation between sympatric populations of these species.

The western bigeyed bug, Geocoris pollens Stål, was successfully reared on a diet of sunflower seeds and eggs and nymphs of the large milkweed bug, Oncopeltus fasciatus (Dallas).

Studies of Quaternary age Coleoptera fossils from North America and Europe plus recent analyses of insect fossils from late Tertiary (Miocene and Pliocene) sites in northern Canada, Alaska, and eastern Siberia show that many of the species composing the present Canadian insect fauna probably evolved during the Tertiary. Thus the history of Tertiary land bridge links between North American and adjacent continents is pertinent for a discussion of the present Canadian insect fauna.

Movement of lithosphere plates has contributed directly to the emergence and foundering of Tertiary land bridges in three key areas: Beringia, the North Atlantic, and Middle America.

A land bridge probably connected Siberia and Alaska in the Beringian region for most of the Tertiary. During the Eocene its climate was such as to allow exchange of tropical to subtropical adapted plants and animals. Paleobotanical evidence suggests that the Beringian area never supported the type of mixed-mesophytic forests called for by the Arcto-Tertiary concept. By the mid-Miocene much of the region north of 65° was probably a rich coniferous forest. Lowland tundra undoubtedly exited on the fringes of Beringia as early as the Pliocene.

Two and possibly three land bridges connected Greenland and Northern Europe during the Tertiary. The DeGeer bridge joined northern Greenland and Norway prior to the opening of the Greenland Sea in the late Eocene – Early Oligocene. The Greenland-Faeroes bridge was never more than a causeway along the route of the submerged ridge now occupied by Iceland. However it persisted longer, possibly existing as a chain of islands as late as the Miocene. A third land bridge may have connected Labrador and Rockall Bank near England during the Paleocene and early Eocene. The climatic history of the North Atlantic region is poorly known, but apparently sites as far north as Ellesmere Island were warm enough during the Paleocene to support subtropical to warm temperate mammalian faunas.

For most of the Tertiary the middle American region remained isolated from South America. Changes in movements of several lithosphere plates created conditions appropriate for north-south island dispersal as early as the Miocene but a true land connection, the existing isthmus, did not form until the Pliocene. Paleontological evidence suggests that tropical conditions were not prevalent there until after that event.

Two new species of Melanotrichus Reuter are described: wallisi from Saskatchewan, and elongatus from Alberta and Saskatchewan. The male genitalia of the new species and those of M. albocostatus Van Duzee and M. atriplicis Knight are illustrated.

The nymph of Coenagrion interrogatum (Hagen) is described for the first time and the nymph of C. resolutum (Hagen) is redescribed. A species key to the nymphs of Coenagrion in Alberta is presented along with characters to separate Coenagrion nymphs from Enallagma nymphs.

Populations of two abundant coccinellid species, Coleomegilla maculata lengi Timberlake and Hippodamia tredecimpunctata tibialis Say, responded rapidly to corn leaf aphid populations [Rhopalosiphum maidis (Fitch)] once the aphids became exposed to predation when the plants tasselled. Coleomegilla m. lengi oviposited at lower densities of aphids than did H. t. tibialis but H. t. tibialis was shown to have a greater numerical response than C. m. lengi at high densities of aphids due to its greater fecundity. The numerical response of the coccinellids by oviposition was linear with a lag of 1/2 week behind the aphid population.

Laboratory tests indicated that phorate, phorate sulfoxide, and phorate sulfone were toxic contact insecticides with broad spectrum activity. In general, p. sulfoxide was most toxic to insects > p. sulfone > phorate. When compared with other insecticides using 24–48 h old field crickets, Acheta pennsylvanicus (Burmeister), as test insects, the three compounds were less toxic by direct contact than carbofuran and fensulfothion, but as or more toxic than aldrin. P. sulfoxide and p. sulfone were strongly inactivated in moist Plainfield sand and were not as insecticidally active in soil against crickets as phorate. Nevertheless, the sulfoxide arid sulfone in soil were intermediate in toxicity between carbofuran and fensulfothion. The insecticidal activity of phorate, p. sulfoxide, and p. sulfone in soil was influenced by soil type, moisture, and temperature. Fumigant toxicity tests indicated that the three compounds volatilized from soil. Chemical analysis showed p. sulfone was most persistent in sand and muck > p, sulfoxide > phorate. Oxidation was observed to be a major degradation reaction for phorate and p. sulfoxide in both soils. Parallel bioassay tests indicated that, in sand, the biological action of "phorate" was due to the joint action of the three compounds. In a field study phorate EC, applied as a broadcast application at 3.4 kg AI/ha and incorporated into the top 7–8 cm of soil was slightly more persistent in muck than in sand. More than 99% and 98% of the applied phorate and its oxidation products disappeared from the sand and muck, respectively, within a year of treatment, indicating that the residues were only moderately persistent under climatic conditions encountered in southwestern Ontario. Low residues of p. sulfoxide and p. sulfone were detected in radishes grown on both soils in the first year but none were present in the second year. No residues were detected in carrots grown on either soil.

Types of cages and methods for rearing, collecting, holding, and scheduling adult emergence are described for hymenopterous parasites of Coleophora laricella (Hübner). Methods differ depending on whether the parasite attacks needlemining larvae, e.g. Agathis pumila (Ratz.) and Diadegma laricinellum (Strobl), or casebearing larvae, e.g. Chrysocharis laricinellae (Ratz.), Elachertus argissa (Walk.), Necremnus metalarus (Walk.), Dicladocerus westwoodii Westw., and Dicladocerus japonicus Yshm. Biological details of the parasites pertinent to laboratory rearing include stage attacked, developmental times, adult longevity, diapause, mode of reproduction, progeny sex ratios, and suggested parasite/host ratios.

Seventeen species of Plecoptera were collected from 58 lakes situated along the Continental Divide in southwestern Canada. Four of the 17 species were found once. The commonest species was present in 25 lakes. At low to middle elevations stoneflies occurred in large lakes that had relatively low total dissolved solids and low maximum annual heat content. The distribution of the majority of species was restricted with respect to lake area and elevation. For example, some species were found only in large lakes at low to medium elevation (900 to 1700 m), while others were found only in small lakes at high elevation (1800 to 2400 m).

Live cultures believed to be aphids of Aphis fabae Scopoli from New Brunswick, Manitoba, and British Columbia were compared by several methods. Cultures from British Columbia lived on faba bean, Vicia faba L., but not on garden nasturtium Tropaeolum majus L. Cultures from Manitoba lived on nasturtium but not on faba bean. Some of the aphids from New Brunswick lived on nasturtium only, and some on faba bean only. The aphids which live on faba bean are believed to be Aphis fabae, and those which will not live on faba bean are considered to be a distinct species.

Pheromone trap density is one factor which influences the magnitude of catch and therefore, should be standardized in a monitoring program. Trap catch increased with the area served by a trap, but reached a plateau when the trap density fell below one trap per 7 ha. From these data a quadratic regression was developed which relates the relative increase in trap catch to trap area. This relationship can be used to compare monitoring data obtained with different trap densities.

The number of moths previously caught in a sticky trap can affect its future performance. In the Pherocon® 2 trap catches began to decline after a cumulative total of 20 to 30 moths and in the Pherocon 1CP after 50 to 70 moths. The catch totals causing a drop in trapping efficiency were correlated with the size of the adhesive catch surface. The cause for the loss in trapping efficiency appeared to be physical deterioration of the adhesive due to moth scales, other insect parts, or dust rather than an olfactory repellent factor. Trapping efficiency was restored by thoroughly stirring the soiled adhesive. Standard maintenance procedures should be followed to keep the adhesive quality of the catch surface constant and thereby prevent a reduction in catches. Tests with two pheromone dispensers, the Codlemone® rubber septum and the Conrel® microfibres, indicated that both are effective for at least 6 weeks. Codlemone septa resulted in higher catches during the first week of field use. During subsequent weeks there was no difference in attractiveness between the two pheromone lures.

A description of the previously unknown larva of Coenagrion interrogatum (Hagen) is presented. In addition, information on larval habitat and the flight period of the adult is documented.

Average duration of the larval stage of Syrphus corollae Fab. reared at 20 ± 1 °C decreased linearly with increase in amount consumed from 9.2 days with 40.9 cal consumed/larva to 7.9 days at 78.1 cal/larva. Mean weight of pupae and percentage emergence of adults increased with calories consumed. No eggs were laid by flies developed from larvae which consumed less than 54.6 cal of energy, equivalent to 38 aphids. Average fecundity increased linearly with consumption up to 81.6 cal/larva (= 58 aphids). Mean reproductive output was 3.2% of larval consumption above 55 cal but decreased as larval consumption increased. When food was scarce, fecundity decreased because pupae, and therefore ovaries, were smaller. Larvae consumed as much as possible in the time available rather than pupating after consuming a minimal amount.

Extracts of eight species of freshwater vegetation were tested for toxicity against larvae of Aedes aegypti L. All extracts were found to be toxic. The same extracts and culture water from one of the species were also tested for their possible influences on the oviposition behaviour of A. aegypti. Extracts of six species repelled ovipositing females; one extract and the culture water attracted ovipositing females; and one extract type had no influence on the oviposition behaviour.

Robsonomyia reducta, new genus and new species, is described from males collected in British Columbia and California. Characters distinguishing it from other genera of Macrocerinae are discussed.

Parthenicus brooksi n. sp. is described and male genitalia illustrated. Cyrtorhinus caricis (Fallén) and Fieberocapsus flaveolus (Reuter) are reported from Canada and North America respectively. Diaphnocoris pellucida (Uhler) is synonymized with D. provancheri (Burque).

Artificial infestations of cereal aphids in caged plants were made at different growth stages of barley in the field in 1978 and 1979. Forty, 80, 160, and 200 aphids/tiller reduced grain yield significantly (P < 0.01) when introduced into caged plants at flowering and milky stages for 2 weeks. Only the 150 and 200 aphids/tiller-treatments gave significant reductions in yield when introduction was at the mealy ripe stage. Twenty aphids/tiller gave a significant reduction in yield only when they were introduced at the beginning of ear emergence and flowering, but not at the milky ripe stage. Significant reduction in percentage protein was obtained only when 160 and 200 aphids/tiller were introduced at flowering and milky ripe stages. The economic injury and threshold levels were calculated as 10–18 and 8–16 aphids/tiller, respectively, depending on rate of increase of aphids, costs of chemical control, and the value of the crop in 1978 and 1979.