Studies on the population dynamics of the cabbage maggot, Hylemya brassicae (Bouché), on cabbage were carried out at two locations in Ontario from 1967 to 1970. Analysis of life-table data for nine generations showed that extensive mortalities occurred during the following age intervals: (1) egg stage; (2) between hatching and the second moult; (3) third-instar larvae; (4) pupal stage. Density dependent mortality occurred only during the latter period. The analysis of age interval survivals and graphical key factor analysis showed that "misadventure" of the larvae between hatching and the second moult was the key factor. The overall mortality process from egg to adult eclosion was density dependent, revealing the importance of pupal parasitism as a stabilizing factor. A predictive model based on density relationships was found to explain 62% of the variance in generation survival. The remainder of the variance is unexplained and may be due to sampling error and/or the influence of factors not measured.

Severely deformed chironomid larvae have been collected in Lake Erie and two lakes in the Okanagan valley of British Columbia. Deformed larvae had very aberrant mouthparts and the head capsules were usually heavily pigmented. In most cases both the head capsule and body wall were many times thicker than in normal specimens. These deformities are apparently caused by pollutants and it is speculated that agricultural and/or industrial chemicals may be responsible.

Platygymnopa new genus, type species P. helicis new species, is described from the northern United States and southern Canada, with type locality McHenry Co., North Dakota. In Montana, P. helicis was reared from larvae feeding within dead snails (Physidae, Aplexa hypnorum (L.)).

A new species, Einfeldia synchrona, is described and compared with a closely related species, Einfeldia pagana (Meigen).

After successfully rearing the pale western cutworm, Agrotis orthogonia Morrison, for years in the laboratory such severe mortality developed in the colonies that further nutritional studies were impossible. The symptoms and effects of the disease syndrome are described. Neither steam sterilization of food and rearing equipment nor use of antibiotics in the food prevented disease. A bacterium tentatively identified as Pseudomonas aeruginosa was isolated from dead insects and when injected or fed to healthy larvae caused the disease. Use of a ’clean room’ and associated aseptic techniques for rearing the insects reduced the numbers of microorganisms in the environment and again permitted the pale western cutworm to be reared successfully.

The life cycle of Leucopis (Leucopis) verticalis Malloch, a chamaemyiid predator of mealybugs, is presented. There are at least two and probably four generations a year in northeastern Ohio, with overwintering occurring as diapausing pupae. Eggs are laid in or near colonies of Pseudococcus comstocki (Kuwana) (Homoptera: Pseudococcidae) infesting such ornamental shrubs as Taxus cuspidata Sieb. and Zucc. var. hicksii Rehd (Japanese yew) and Euonymus Fortunei (Turez.) Hand-Mazz. (wintercreeper). The incubation period requires 48–72 hours at 21°–25 °C. Larvae complete development in 12–15 days. Larvae feed by breaking through the integument of the prey with their mouthhooks and sucking out the body contents. Each larva usually kills all of the immature mealybugs within a colony before attacking the stem mother. Puparia are formed within the remains of the destroyed colony. The pupal period of non-diapausing pupae requires about 12 days. Pupae formed after mid-September enter diapause and overwinter. The entire life cycle in nature can be completed in 33–42 days if no diapause intervenes.The egg, three larval instars, and puparium are described and illustrated.

Daily emergence of Scolytus ventralis Lec. from infested white fir bolts was highest in early afternoon (1200–1600 hours, P.D.S.T.) and limited to periods when air temperature exceeded 21 °C. More females than males emerged each day; the ratio in the total emergence was 1.9:1 and as high as 2.8:1 on warmest days. Flight occurred from mid-July to mid-September, with peak flight in mid-August. The intensity of flight activity was positively associated with varying temperatures above 24 °C (threshold).Visitation rates on lower boles of white firs were 10 times higher than those on Jeffrey pines. Two to three times as many beetles were trapped near girdled or severed white firs as about uninjured firs. Severed trees under attack by S. ventralis attracted three to seven times as many beetles as uninjured firs. When attack density reached 10 to 13 mines per sq. ft, the large number of beetles attracted in flight did not initiate mines in the trees already attacked but attacked surrounding host trees. Sex ratios of beetles trapped at experimental and control trees did not differ from that at emergence.

Thirteen species of black flies in two genera were found in the Crowsnest and Oldman rivers of southern Alberta. Of these, 11 were in the genus Simulium and 2 were in the genus Prosimulium. The two species of Prosimulium were found only in the Crowsnest River. Three species of Simulium were found only in the Oldman River, three only in the Crowsnest River, and 5 were found in both rivers.

Larvae of the blowfly Lucilia sericata were shown to require more sodium in their diet than do larvae of Pseudosarcophaga affinis. A chemically denned diet, originally designed for P. affinis, and modified by the addition of agar to suit L. sericata, was further improved by substituting 0.04 g/l. of NaOH and an equivalent amount of KOH.

A bioassay with elder pith wafers was developed to measure sustained feeding of the pales weevil, Hylobius pales (Herbst). Sucrose, fructose, glucose, and extracts of phloem of loblolly pine (Pinus taeda L.) were compared in three-choice experiments. Intensity of feeding indicated a synergistic effect occurred when sucrose and phloem lipid were present together. The non-polar or neutral lipid fraction of phloem stimulated more feeding than did the polar lipid fraction.

Blue, a non-sex-linked mutant of the green lacewing, Chrysopa carnea Stephens, is recessive and shows complete penetrance. Unlike the coloration of the larva or imago, egg colour, which is due to the yolk, is the same as that of the maternal phenotype.

One hundred and sixty species of arthropods, representing 137 insects, 19 mites, and 4 spiders, were collected or reared from the cankers of the comandra blister rust, Cronartium comandrae Peck, on lodgepole pine, Pinus contorta Dougl. var. latifolia Engelm., in southwestern Alberta. The insects damaged 40 to 60% of the cankers observed in any one year and reduced aeciospore production by 10%. Eleven orders of insects were represented, of which the Coleoptera (29 species), Lepidoptera (14), Diptera (21), and Hymenoptera (38) were the most important. Epuraea obliquus Hatch, Paracacoxenus guttatus Hardy and Wheeler, and a Mycodiplosis species appeared to be true mycetobionts. Several others which damaged the cankers, such as Pissodes schwarzi Hopk., Cylindrocopturus deleoni Buchanan, Ernobius sp., Corticaria sp., Bradysia spp., Dioryctria spp., Laspeyresia sp., Grapholitha sp. prob. caeruleana Wlshm., Eucordylea spp., Cinara spp., and Diapterobates principalis (Berlese) could be classied as mycetophiles. About half the species appeared to be mycetoxenes. New habitat or host information was obtained and several new species were collected. Several of the genera represented have been reported to occur on other pine stem rusts, which indicates that the rust cankers provide a suitable habitat for development.

A small microenvironment cabinet was constructed to facilitate studies on the influence of temperature, humidity, and light on the efficacy of chemical pesticides. The semi-jacketed system operated in the ranges of 4°–36 °C, 20–90% relative humidity, and 0–180 ft-c.

Einfeldia synchrona Oliver is univoltine in a small, shallow, highly eutrophic pond near Ottawa (45°N.). Adult emergence is synchronized with slight protandry in May, and from this small pond exceeded 145,000 individuals in 1970. Emergence is inhibited experimentally at short photoperiods. More than one egg mass is produced, during a period of several days following emergence. First instar larvae, which lack ventral tubules, are at first pelagic but build cases before moulting. The remaining three larval instars possess 1 pair of ventral tubules. Larvae show a preference for central areas of the pond over 40 cm deep, and show some mobility in response to seasonal depth changes. There are arrests in the development of larvae both in winter and during summer, with cessation of feeding, penetration into the mud, and construction in winter of special sealed cocoons. Marked year to year differences in the stage reached by winter, and in the larval population level, were detected. Many of these biological features are probably widespread in Chironomini and hence of some importance in the interpretation of studies of the bottom fauna.

The Malpighian tubules of Hypoderma are endodermal in origin. There are two pairs, each pair uniting to form a common duct. The origin and distribution of the tubules in the first instar larva is different from that of the second and third instars; however, in these two later instars the pattern is similar. The lengths of the tubules in each stage of development depend on the degree of coiling. The musculature connecting the tubules, dorsal vessel, and hindgut are described.

For 100% mortality, concentrations of potassium capricate, 0.0009 to 0.005 M, are very effective insecticides against Aedes aegypti (Linnaeus), particularly larvae, in the laboratory (23.00° ± 0.1 °C) within 1 to 5 days. And likewise potassium capricate, 0.001 to 0.002 M, and variously applied capric acid per se are effective against native mosquitoes in water pools in the field (5°–16 °C). With dosage–mortality tests of potassium capricate in the laboratory, larval mortality in A. aegypti was directly dependent on concentration, time, and age, tolerance increasing with age of the larvae. Although pupae seemed little affected, about 60% of the adults formed died during eclosion in 0.003 to 0.005 M mostly within 3 days. Admittedly these substances kill fish, crustaceans, and other insects, but in the field, treated pools soon regained living inhabitants. Some evidence shows that capric acid may be the least liable to endanger fish. Advantageous properties of these long-recognized insecticides include that both kill mosquitoes, both are easily biodegraded to harmless simple components, and both are readily metabolized by mammals.

A new species of Forcipomyia from Singapore is described in all stages. Although the female adult could be placed in Lepidohelea Kieffer (1917) by the possession of scales in addition to bristles and hairs, the male genitalia are distinctive. A new subgenus, Schizoforcipomyia, is erected to accommodate this species whose larva has a bilobed anal pseudopod and whose male genitalia are intermediate between Forcipomyia s. str. and Proforcipomyia.

The effects of temperature on survival during postdiapause development of the pre-imaginal stages of the larch sawfly, Pristiphora erichsonii (Hartig), were investigated in the laboratory using Manitoba material. Pronymph mortality increased progressively between 10° and 30 °C. Developmental arrest occurred in pronymphs exposed to 35 °C for periods up to 10 days prior to their transfer to 15 °C for completion of development. Pupae were more tolerant of high temperatures than were pronymphs.The results are discussed in relation to the possible physiological mechanism involved and the ecological implications for survival in the field.

Populations of Chironomus tentans from Iowa and Wisconsin show consistent polymorphisms for inversion sequences of chromosome 1 which are associated with sex. Male larvae from Iowa populations are invariably heterozygous for a sequence of the left arm which is never present in females. In a Wisconsin population, however, females are consistently heterozygous for a dominant sex factor, female determiner (Fd), linked to but not inseparable from an inversion sequence of the right arm. Two primary loci for sex determination appear to have evolved different dominance relations in these races.