The macro-leafhoppers (Cicadellidae, exclusive of Typhlocybinae) of Manitoba are recorded with distribution and host records for the province, seasonal occurrence of adults, ecological associations, and recent taxonomic changes. These comprise 240 species, including 95 new provincial records, of which 22 are new Canadian records, and 1 is a new nearctic record, ldioccrus marginalis Vil. The westward spread of Athysanus argentarius Mete, and Doralura stylata (Boh.) is commented upon.

Acyrthosiphon pedicularis is described and illustrated and a key to the Canadian species of Acyrthosiphon is given.

Infectivity tests revealed that sensitivity of larvae of Archips cerasivoranus Fitch to infection by a commercial preparation of Bacillus thuringiensis Berliner depends on the physiological condition of the insects (determined by age and nutrition), and temperature, but mostly on the presence or absence of infection by the microsporidia Plisliphora sp. and Nosema cerasivoranus Thomson.

Mortality attributable to the bacillus was 90, 40, and 30% for healthy third-, fifth-, and seventh-instar larvae after 20 days, mortality reached 90% after 3, 9, and 19 days for larvae of the same ages naturally infected by microsporidia. Also, low temperatures decreased the effect of the pathogen and starvation reduced the resistance of larvae to infection.

The results obtained suggest the action of B. thuringiensis in this tortricid is to provoke generalized septicemia rather than toxemia.

Other infectivity tests made with cultures of B. thuringiensis and Bacillus cereus Frankland and Frankland confirmed these results. The action of the two bacteria was similar, both provoking septicemia in the insect. This effect was considerably increased by the presence of protozoan diseases.

Analyses of unsaturated lipids by the iodine number method showed that infection by a microsporidian or B. thuringiensis lowered considerably the energy value index. The index reached 13.0, 25.5, and 27.0 in healthy larvae of third-, fifth-, and seventh-instar, was reduced to 5.2, 17.0, and 15.0 by a microsporidian infection, and to 7.5, 18.0, and 22.5 by a B. thuringiensis infection. When an infection with both pathogens was induced, the value decreased to 4.0, 8.0, and 7.5.

Distributional and anatomical characteristics of the species of the western North American genus Cordylospasta are analyzed. The current concept of this genus is a considerable modification from that of earlier classifications.

Of the two species belonging to Cordylospasta, C. fulleri Horn is unique among North American blister beetles in having antennae with 8 to 10 antennal segments. This species is strictly allopatric to the second species, C. opaca (Horn), in which the antennae are 11-segmented.

Step-clinal geographic variation in seven anatomical characters is recorded for C. opaca. On this basis six biological races are recognized as occurring in central and southern California. These are considered the equivalent of subspecies. An informal approach to the recognition of these infraspecific taxa is followed since, due to limited material, interracial reproductive relationships cannot be inferred confidently at the present time.

Only one parasite species survived on most housefly (Musca domestica L.) pupae multiparasitized by any two of Nasonia vitripennis (Walk.), Muscidifurax zaraptor K. & L., or Spalangia cameroni Perk. N. vitripennis and M. zaraptor were both intrinsically superior to S. cameroni if the attacks on the hosts by their females preceded, were simultaneous with, or followed by up to 48 hours those by females of S. cameroni. N. vitripennis was intrinsically superior to M. zaraptor if its attack preceded that by M. zaraptor by at least 24 hours; M. zaraptor survived when it oviposited before N. vitripennis; and neither species was consistently superior to the other when their attacks were simultaneous or that by N. vitripennis closely preceded that by M. zaraptor. N. vitripennis often survived on multiparasitized hosts because of its rapid development and rapid and thorough host utilization which caused its rivals to starve. In contrast, M. zaraptor’s success was a consequence of its prédation on eggs and larvae of its competitors and to a lesser extent its moderately rapid development and host utilization. S. cameroni was usually intrinsically inferior to both of the other species because, in spite of being predaceous on their larvae, it developed much more slowly and seldom attacked their eggs. The significance of these qualitative characteristics in insect parasites used in biological control programmes is discussed.

Laboratory investigations were made to determine the persistence of aldicarb and its metabolites in soil (clay loam pH 6.8–7.2) and in water collected from fields. At dose rates of 15 and 20 p.p.m., aldicarb was not detectable in soil after 8 and 12 weeks, respectively. At 50 p.p.m., after 11 weeks chemically detectable amounts of the insecticide were present in the soil.

Soil samples were stored between 23° and 28 °C but temperature at times reached 32 °C.

In field water treated in the laboratory at 100 p.p.m. of aldicarb, the chemical and its metabolites were detectable at 0.4 p.p.m., 11 months later. Water was stored at 16°–20 °C and was exposed for 507.5 hours to sunlight.

Aldicarb was eluted readily with water from soil columns.

When aldicarb was applied as side dressing at the time of planting of sugarbeet roots and potatoes, residues of less than 0.05 p.p.m. were found in soil and potatoes at the time of harvest. One sugarbeet root sample contained 0.2 p.p.m. of the chemical and its metabolites.

The number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

Average fecundity of free-living and caged female Psylla pyricola Foerster on pear trees was reduced by high summer temperatures and low host vigor. Implications of these observations in the planning of control programs is discussed.

Tanaoscelio cornopis n. gen. and n. sp. (Scelionidae: Scelioninae) is described from Trinidad, W.I. Specimens were reared from eggs of a grasshopper, Cornops longicorne (Bruner) (Orthoptera: Acrididae), found in leaf petioles of water hyacinth, Eichhornia crassipes (Mart.) Solms. (Monocotyledones: Pontederiaceae). The new genus is compared with the related genus Scelio Latreille.

These preliminary investigations of effects of radiation on black flies were undertaken to develop methods of control based on the "sterile-male" technique. Mature black fly larvae were irradiated at various exposures (from 2 kR to 32 kR) and allowed to complete development in aerated stream water in the laboratory. The larvae were preponderantly Simulium venustum Say, determined by inspection of pupae and adults. It was found that percentage pupation following irradiation remained at a fairly constant level (about 93%), whereas emergence from pupae fell from 54% at 2 kR to 0% at 28 kR. Though variable, the percentage emergence of the controls averaged 47%. Adults inspected for radiation damage appeared unchanged at the lower doses, e.g. 2 kR to 6 kR, compared with controls. At higher doses (e.g. 16 kR) the abdominal cavities usually showed a notable decrease in stored fat bodies. The anterior two-thirds of the abdomens were largely devoid of internal organs, many of which, including the ovaries and testes, were found in a degenerate condition at the posterior tip.

Allometric growth of antennal and leg segments was studied in five species of mirids, namely, Adelphocoris lineolalus (Goeze), A. rapidus (Say), Lygus lineolaris (Beauv.), Polymerus basalts Reuter, and Plagiognathus chrysanthemi (Wolff). The study revealed that growth ratios of both A. lineolatus and A. rapidus varied in parallel fashion in homologous segments of L. lineolaris and, that those of P. chrysanthemi varied similarly with L. lineolaris and P. basalis. It was also found that segments with relatively high growth ratios were less different in magnitude than slowly growing segments when both A. lineolatus and A. rapidus were compared with L. lineolaris and P. basalis. Growth ratios of head width were similar for the five species. The probable evolution of relative growth was discussed.

The leafhopper Erythroneura ziczac Walsh is the most important insect on grape in the Okanagan Valley, B.C. Hairy-leaved varieties of grape are relatively resistant to attack. The leafhopper has two overlapping generations a year and overwinters in the adult stage. Its chief natural enemy is a mymarid egg-parasite, Anagrus epos Girault, which overwinters in the eggs of other species of leaf-hoppers on wild rose and apple so that intensity of parasitism of E. ziczac can be influenced by proximity of those plants to vineyards.

The host-finding search patterns of Coeloides brunneri Viereck, a braconid parasite of Douglas-fir beetle larvae, were studied by visual observations and from tracings of the parasite’s path on a plastic cylinder wrapped around a beetle-infested log on which the parasite was searching. The female parasite locates its host, lying under approximately.6 cm of bark, through four distinct phases of host finding: random search, nonrandom search, oviposition, and nonsearch (resting and cleaning). Random search is characterized by large areas of bark being examined in a relatively straight path. Nonrandom search is a highly intensified examination of a small bark area and numerous turns of greater than 70°. Nonrandom search is initiated only at the end of a bark beetle gallery. Ovipositional probes are the culmination of successful host finding, in which the parasite paralyzes the host and deposits an egg. C. brunneri searched effectively on both Dendroctonus pseudotsugae Hopkins in Douglas-fir and D. ponderosae Hopkins in ponderosa pine, although there was a slightly more efficient search on D. pseudotsugae. The percentage of time spent in each search pattern was identical in 90-minute and 24-hour tests. A stimulus associated with the end of a larval gallery was concluded to be the key stimulus by which the parasite recognizes its host. Amputation experiments showed that the antennae are the principal receptor organs used in host finding. Various experiments and observations produced no evidence that sound or vibrations produced by the host, sound produced by the parasite (sonar), magnetism or odor of the host, or its host tree are used in host finding.

A chemically defined, synthetic medium that induces oviposition in the parasite Itoplectis conquisitor (Say) has been developed. The medium contains serine (0.5 M), arginine (0.05 M), leucine (0.065 M), and magnesium chloride (0.025 M); and it is more effective than host haemolymph in inducing oviposition. This completely artificial oviposition stimulant was developed to facilitate the mass rearing of the parasite on an artificial diet.

Seventeen species of parasitic Hymenoptera were found associated with balsam gall midge in Maine. Tetrastichus marcovitchi (Cwfd.), Tetrastichus sp. near solidaginis Burks, Plalygaster mainensis MacG. and Osgd., and P. abicollis MacG. and Osgd. were the most abundant known parasites, while several other species, some of uncertain status, were less frequently encountered. A key is presented for commonly encountered species, and details of the life histories are given for important midge parasites.

Larvae of Leptinotarsa decemlineata (Say) reared on tomato fed longer, consumed more foliage, and had a lower survival rate than when reared on potato, its principal host. On both plants, a direct linear relationship was obtained between food consumption and larval growth. Potato was the more efficient of the two plants in terms of food conversion to body matter. This was reflected by increased weight gain of the larvae and greater pupal size.

Adults from larvae reared on tomato were smaller and less fecund than those from larvae reared on potato. Half of them rejected tomato as food. However, egg-laying increased when they were transferred to potato after 50 days. The present investigation indicates that L. decemlineata can survive and attain maturity on tomato in the absence of its principal host plant. However, when potato is once again available, it is able to increase growth, accelerate development, and achieve a greater reproductive potential.

The external and internal female genitalia of the North American species comprising the Cicindela maritima group are described and figured. An identification key based on these structures is provided. A phylogeny based on the female genitalia is postulated for the group.

Distinct differences were observed in postdiapause development and prolonged diapause of the larch sawfly, Pristiphora erichsonii (Hartig), obtained from the vicinity of Tazin River, Northwest Territories; near Riverton, Manitoba; and near Renovo, Pennsylvania. All populations had been reared under controlled laboratory conditions (21°±0.5 °C, 50±10% relative humidity, and a 15-hr daily photophase) for two or more generations.

After 280 days cold treatment at 3°±1 °C, cocoons were dissected and the number of pronymphs and eonymphs was determined. Insects from each population were then reared at 5°, 10°, and 15 °C. Times to adult emergence, duration of individual stages, and numbers remaining in prolonged diapause at each temperature were determined.

The most significant differences occurred among populations reared at 5 °C. At this temperature, the times to adult emergence and the duration of individual stages of development and the proportions remaining in prolonged diapause or arrested development, increased from northern to southern latitudes. Less significant population differences were noted at 10° and 15° than at 5 °C.