Adults of B. cephi emerged at the same time as the adults of their host, the wheat stem sawfly, and started to oviposit about mid-July. The second generation started to emerge between August 5 and 15. This generation, which was complete in some years, was apparently only partial in years in which adults of the first generation continued to oviposit late in the season. In most cases the larvae of Bracon that were present at harvest time were from eggs laid after August 1.

Most of the overwintering B. cephi were located in the lower internodes of the sawfly-infested wheat stems. Although B. cephi attacked some sawfly larvae in their stubs most sawflies escaped parasitism once they had cut their host stems.

High host densities per stem in hollow-stemmed wheats were detrimental to Bracon during the early part of the season as the unparasitized sawfly larvae in stems containing B. cephi destroyed the parasite larvae.

The sawfly-susceptible wheats were more suitable than the resistant for parasitism. Generally, differences in parasitism between wheats and between barleys were caused by differences in length of survival of the sawfly larvae in the different host plants; longer survival led to higher parasitism.

The fluctuations in amounts of parasitism mainly depended on the synchronization of development between B. cephi and the sawfly. Parasitism increased when the sawfly larvae cut their host stems sufficiently late to allow establishment by the second generation of B. cephi and decreased when the sawfly cut too early for parasitism by the second generation. The date of ripening of the host plant governs the date of cutting by the sawfly; hence, the amount of parasitism is influenced by the levels of soil moisture and temperature during the growing season, by differences in rate of development of various plant hosts, and by the date of seeding. Low levels of parasitism resulted from early ripening of the sawfly host plants in two consecutive years, whereas a moderately high level occurred even though the weather of the current year was conducive to early ripening, provided that the wheat in the preceding year had ripened late. It appears that moderate to high levels of parasitism required that the crop ripen late in at least one year out of two.

The susceptibility of the spruce budworm, Choristoneura fmiferana (Clemens), under laboratory conditions, to commercial preparations of Bacillus thuringiensis var. thuringiensis Berliner was reported by Angus et al. in 1961. This bacterium was recently tested, under field conditions, both as dusts and sprays. The results of ehese tests are presented here with comments on the effect of the environment and other factors.

Collections of aphids on cereal grains and grasses in Manitoba were made during the years 1958-62. The species collected are important because of their possible economic injury to cereal crops and also because several of the species are known vectors of the barley yellow dwarf virus of barley, oats and other Gramineae. Bruehl (1961) listed all known hosts of the virus, mostly determined in greenhouse inoculation trials. He emphasized the importance oi the feeding habits of aphids under natural conditions in the field. In 1962 most species of aphids on Gramineae were present in unusually large numbers in Manitoba, and an excellent opportunity was afforded to obtain records of breeding colonies on 38 host plants, many of them in the Forage Plots of the Department of Plant Science, University of Manitoba. The host plants and aphids are listed in Table I. The aphid species were determined by W. R. Richards, Entomology Research Institute, Ottawa, or by the senior author.

During the course of a study of the bionomics of the pitted ambrosia beetle, Corthylus punctatissimus Zimm., in southern Ontario in 1959, the method of overwintering fungal spores and their transmission from brood galleries to healthy plants by the beetles was determined. This process was not clearly understood with respect to any of the ambrosia beetles until recently when Francke-Grosmann (1956) described in detail the different structures, present in several species of Platypodidae and Scolytidae, used in storing fungal spores. In Scolytidae she found that the females of some Trypodendron species store spores in tube-like structures within the prothorax (invaginations of the prothoracic wall); that females of Xylosandrus germanus Bldf. and Anisandrus dispar Fabr. keep spores overwinter in shallow pouches in the intersegmental membrane between the pronotum and mesonotum; that females of Xyleborinus saxeseni Ratz. store them in a small cavity at the anterior edge of the elytra; and that females of Xyleborus pfeili Ratz. store the spores in a receptacle on the “posterior” abdominal tergite. In some species of Platypodidae she found somewhat similar structures in both males and females. In 1959 Fernando (1959) described spore storage by the shot-hole borer, Xyleborus fornicatus Eichh. He found that females store spores in sacs on either side of the head, situated anterior to the brain, and that the sacs open by ducts into the upper part of the oral cavity.

In recent years there has been an increase in the number of papers dealing with the family Cupedidae, but in spite of the revised interest in this group there is still no publication which treats the family on a world-wide basis and provides keys for separating all the genera and species. According to Janssens (1953), the family contains 22 species belonging to five genera. Recently, Neboiss (1959) added three new species from Australia and erected a new South American genus, while Papp (1961) described a new species from California. In this paper I will bring the available information on the Cupedidae together and present a list of fossil forms, a series of keys to the genera and species, and an account of their geographical distribution. In addition, I propose three new synonyms in the genus Cupes.

The percentage of eggs deposited by Drino bohemica Mesn. on a species of host in preference to other hosts on successive days through the oviposition period of the parasite fluctuated continually within a comparatively wide range. The fluctuations in the selection of hosts within a generation apparently had little influence on those between generations. There was no significant relationship between the percentage of attacks on one species of host and the age of the parasites. Individuals within a group may select a different host than that preferred by the group as a whole.

This is the first of a series of papers which will consider the systematics of the Canadian and Alaskan Fulgoromorpha. The aim is to produce eventually a work on the Fulgoromorpha similar to that on the Cicadellidae of the same area by Beirne (1 956).

The two Delphacid genera Achrotile Fieber and Laccocera Van Duzee can be recognized by the presence of distinct pits on the frons, notum and abdominal dorsum. The frons in Achrotile has two median parallel carinae whilst only one is present in Laccocera.

In this paper a new species of Glyphina Koch is described. This genus has not been previously recorded from the Western Hemisphere.

Unlike most other arrhenotokous species, D. fuliginosus females cannot control fertilization of their eggs and in an optimal environment the sex ratio of any one strain is constant. Variations in the sex ratio occurred when unfavourable environmental conditions prevailed before, during and immediately following mating. Beyond half their life span, males inseminated less than half the females they mated and the inseminated females produced fewer female progeny. Temperatures above 27 °C. during post-embryonic development sterilized otherwise functional males but had much less effect on females. Structural defects of either sex were rare. Mating was successful only within the normal range for optimal adult activity. Although females were inseminated by more than one male, the sex ratio of their progeny was not affected. Larval mortality from superparasitism above 65 larvae per host differentially favoured survival of males, heightening the incidence of pairing in nature at low host population densities. The percentage females was significantly reduced when oviposition was interrupted, or delayed by low temperature, providing a possible explanation for the numerous reported differences in the sex ratio between laboratory and different geographically located populations.

Experiments indicated that pollen does not increase the length of life of the males of Scambus buolianae. Various pollens significantly increased either fecundity or longevity, or both, of the females. The greatest fecundity and longevity resulted from the addition of wild carrot and tulip pollen, Goldenrod, oriental poppy, or snapdragon pollen improved fecundity, while birch and ragweed pollen affected longevity only. Parasites have a greater chance of establishment in areas where they can find a rich vegetation of nectar- and pollen-producing plants, than in areas lacking such flowering plants.

The habits and dispersal of the pteromalid parasite Nasonia vitripennis and its housefly host, Musca domestica, and their density relationships were investigated. Male parasite longevity averaged 1.62 days and female longevity 6.96 days. The average number of progeny per female parasite was 139.8. When 25 pairs of parasites were placed with 300 housefly pupae of three sizes, the percentage parasitism was 45.0 for the small (less than 2.0 mm. in diameter), 72.8 for the medium (from 2.0 to 2.5 mm.), and 65.7 for the large (greater than 2.5 mm.). The number of parasites produced per parasitized pupa was 2.20 for the small, 4.30 for the medium, and 6.11 for the large pupae. Increasing the extent of superparasitism produced significantly smaller parasite progeny. A significantly greater normal mortality occurred in small housefly pupae (21.5 per cent) compared with either the medium (6.3 per cent) or the large (5.2 per cent).

The parasite dispersed significantly faster when unfed than when fed. Housefly pupae which had been previously exposed to parasites also stimulated the tendency for subsequent parasite emigration. Housefly dispersal was found to be density-dependent under the experimental conditions of the multi-cell population cage.

With an increasing parasite-host ratio the rate of parasitization increased until all hosts at a 1 to 1 ratio were parasitized in 24 hours; percentage of parastized hosts producing parasites reached a peak of 71 per cent at the 1 to 2 ratio; and above the 10 to 1 ratio all parasite progeny died due to super-parasitism.

The two species described here were discovered during studies on a revision of the Ips of North America. They belong to a group of closely related species composed of Ips tridens (Mann.), I. engelmanni Sw., I. yoboensis Sw., I. pilifrons Sw. and I. sulcifrons Wood. The females in this group have the lower part of the front of the head slightly elevated as in I. yohoensis to very strongly protuberant as in I. tridens. All of them breed in species of spruce. The males of this group are difficult to determine from external characters alone. Descriptions were made under a magnification of 50X, using 100X occasionally.

During four months of 1961 I had the opportunity of investigating and illustrating numerous species of Lepidoptera on the Island of Tutuila, American Samoa.

This was made possible through the cooperation of Mr. and Mrs. M. T. Hollingsworth of the Educational Division of the Samoan Government, the Director of Agriculture, Mr. Noel Bayless, and the Governor, Mr. H. Rex Lee.

Quarters and laboratory facilities were made available at the newly leased Agricultural Experiment Station of Mulinu'u, an 18-acre tract richly covered by native vegetation and cocoanut palms. The residence, formerly owned by the previous Governor, Peter Tali Coleman, was supplied with electricity, which made possible the use of neon and black light.