Logging slash constitues an environment supporting a particular association ot insacts and other arthropods. Initially, the species of insects in the community are governed by the character of the slash, that is, the tree species, thickness of bark, and size of tops. The condition of the slaah changes with the passage of time, the rate of change being directly affected by bark beetles and wood borers which initiate the ingress of wood-destroying fungi. As the environment changes, those species, for which the habitat is no longer suitable, drop out, leaving in the association of animals only those which can exist under the new conditions. The succession of communities of animals inhabiting slash, logs, dying and dead trees has been shown by Adams (1915) and Savely (1939) to continue until the wood has disintegrated completely. The community of insects and other arthropods invading red and white pine logging slash during the first summer following winter logging has been examined during this study. One object of the study was to determine the importance of the development of broods of various species of bark beetles in the subsequent establishment of other arthropods in the community. Wherever possible, from original observations or from works of other authors, the role of each species in the particular environment has been indicatad. Seasonal history notes have been prepared tor each species of bark beetle found in the slash.[...]

Since the advent of DDT and other new organic insecticides, phytophagous mites, particularly those of the family Tetranychidae, have occupied increasing attention from economic entomologists. When these insecticides were applied, as controls for certain insect pests, it was found that in almost every case populations of mites increased to such an extent that further chemicals were required to control the mites. Theories were early advanced, and later substantiated, that the newer insecticides, particularly DDT, were harmful to predators of mites. Mites increased to tramendous populations when released from the control previouely exercised by their predators. It, therefore, became imperative for economic entomologists not only to find newer and better acaricides, but also to determine through biological studies what arthropods are predacious on plant-feeding mites. This study belongs to the latter category. It was initiated in 1950 with a threefold objective: to determine what species of Tetranyohid mites are of economic importance in Manitoba; what predators are present for natural control; and what relative value each predator bas as a natural control factor. The information contained herein was accumulated during the years 1950 and 1951. Prior to this time no work had been done on predators of mites in Manitoba. In two years the important mite species and their principal predators have been identified.[...]

The two-spotted spider mite Tetranychus bimaculatus Harvey has long been one of the most serious pests attacking cucumber in greenhouses. This pest is of particular economic importance in Essex County, Ontario, where cucumber culture under glass is a major commercial practice. Each year mite infestations result in a ten to fifteen per cent loss of a $3,000,000 crop. The recently developed aerosols of parathion and related phosphoric acid esters have been highly effective against active forms but have had little or no ovicidal effect. Such controls are costly as they must be repeated at intervals of time to prevent further mite population build-up from the unaffected eggs. The most effective of these chemical controls have on occasion resulted in the selecting out of resistant strains of the pest, thus defeating their own effectiveness. Many workers have, therefore, turned their attention to the investigation of non-chemical methods of controlling these mites on greenhouse plants. One suggestion has been that controls might be effected by the manipulation of plant nutrients in the soil (Page, 1946; Rodriguez and Neiswander, 1949). This led the writer to undertake a controlled nutritional experiment at the Dominion Entomological Laboratory, Harrow, Ontario, in an attempt to ascertain the effect of various levels of nitrogen, phosphorus and potassium on the fecundity of the two-spotted spider mite Tetranychus bimaculatus Harvey. [...]

In May and June of 1948, a huge fire swept the Mississagi region of Northern Ontario and left in its wake the dead and dying remains of a once great pine forest. Studies on the part played by wood-boring insects in the deterioration of the standing, burned timber were initiated the following year. Most of the damage to the firekilled trees was found to be caused by two cerambycids, Monochamus notatus (Drury) and M. scutellatus (Say). The biology of these beetles is discussed by Craighead (1923, 1950). The two species are commonly separated on the basis of colour (Knull, 1946). M. notatus is dark brown with lighter brown elytra and is covered by a greyish-white pubescence, while M. scutellatus is usually a shining black (Plate 9). The scutellum of each bears a dense, white pubescence which, in M. notatus, is divided by a bare, median line. Such a line also occurs in M. scutellatus but it is usually incomplete. The elytra of the females are generally marked by elongate spots. Length is also used to separate the two species. For example, Chagnon (1938?) gives the range of length for M. notatus as 27-32 mm. and that for M. scutellatus as 19-24 mm. Actually, no such clear-cut difference in size ranges occurs; instead, a very considerable overlap is found in the field. It was also apparent in the field that the two species acted almost as one population. Both caused the same type of damage, and bred freely in the same locality at the same time and in the same host trees. [...]

Many investigators have sought evidence on how and where DDT (l, l, l-parachlorodiphenyl trichlorethane) penetrates the insect body and where it effects its lethal action. Disagreement in the results and interpretation of results still leaves much doubt as to where penetration is most easily effected and the writer could find no good evidence in the literature pointing at all conclusively to any site of DDT action. Definite information on these points should be of value in formulating DDT insecticides and designing methods for their use.

Rehn and Hebard (1915) listed forty-seven names in synonymy under the original name, Acheta assimilis Fabricius, 1775. Recent studies by Fulton (1952), Alexander (1957), Alexander and Bigelow (1960) and Bigelow (1958 and 1960) have revealed the presence of a number of distinct, reproductively isolated species. All these writers recognized biological evidence as being of primary importance in taxonomic studies of American field crickets.

The first description of an American field cricket of the genus Gryllus was published by Fabricius in 1775 when he described Acheta assimilis from Jamaica. By beginning of the 20th century no less than forty-seven New World species of Gryllus had been described (Blatchley, 1903), thirty-three of these were as recognized valid by Kirby (1906). Practically all the early workers on this group considered macro-morphology only: such characters as size, coloration, wing venation, body proportions, number and relative length of tibial spines, and the length of tegmina, wings, ovipositor and the hind femora.

This study of Hypomolyx piceus (De G.) was initiated in 1951. The need for the study arose indirectly through the Laboratory of Forest Pathology, Canada Department of Agriculture at Saskatoon. Members of that laboratory, while investigating root diseases of white spruce in Manitoba and Saskatchewan, discovered root – wounding by the larvae of this insect. Since it was thought that there might be a relationship between this wounding and the incidence of disease, a co-operative study of the insect and root diseases of white spruce was undertaken.

The term synergism as applied to a type of action of mixtures of poisons has been diversely interpreted in the literature. Macht (1929) used the term to describe the effects of mixtures of poisons which did not represent a summation of the independent effects of the chemicals used. He included both potentiation and antagonism. lmnan (1929) introduced the term activator to describe any material of low toxicity which increased the effectiveness of an insecticide. Haller et al. (1942) used the terms synergist and activator synonymously to describe the action of sesamin in increasing the effectiveness of pyrethrum sprays.

Field and laboratory etudies of the onion maggot Hylemva antigua. (Meigen), its li fe history, depredations, host range and preference, predators, and importance relative to associated dipterous species, were conducted in a commercial onion growing district, on muck soil, at Ste-Clothilde, Q,uébec, during 1952. The insect went through three generations in the year. It overwintered as a pupa. Egg laying commenced late in May. Comparison with other etudies showed the life history to be unaffected by the muck soil habitat.