Investigations have shown that several types of reproduction commonly occur in the Coccoidea. Some soecies reproduce in the usual sexual manner. some parhenogenetically, some by either of these two methods depending upon whether or not fertilization takis place; others reproduce hermaphroditically. The type of reproduction is not confined to any particular group but is found throughout the superfamily.

The relationship between the fate of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), and distance from small-mammal tunnels was studied during 1958 in the Whiteshell Forest Reserve of eastern Manitoba. The objects were to determine the distance that small mammals can detect cocoons and to observe possible effects of the interactions of small-mammal predation and other natural mortality factors of the insect. Additional analyses of the data provided information on the behaviour of the predators and the ecology of the prey insect.

Stands of black spruce, Picea mariana (Mill.) B.S.P., in Northern Manitoba and Saskatchewan were defoliated by insects from 1954 to 1955 (Prentice and Hildahl, 1955). The defoliation was sufficient to show reddening of the tops from the ground as well as from aircraft at an elevation of 1,000 feet. Collections showed clearly that the most abundant species was the black-headed budworm, Acleris variana (Fern.); larvae could be found at all crown levels. Other species of insects were also common in the tops of trees with dense compact foliage such as often found in “club-tops” of black spruce. The reddening of foliage was not noticeable after the decline of the black-headed budworm populations in 1956, but the numbers of the other insects, which formed a “complex” of species, persisted at varying levels of abundance in the tops of black spruce.

Horse flies and deer flies were collected throughout the spring and summer of 1955 by the author and others in the vicinity of the Wildlife Research Station, Algonquin Park, Ontario. These collections include 2,712 females of 15 Chrysops species, three males and 278 females of 13 Tabanus species and one female of Stonemyia tranquilla (O. S.). However, tabanids collected in other years from the Park have been studied as well. In 1955 T . trepidus McD. (35%) and T. epistates O. S. (15%) together accounted for half the Tabanus species collected, and C. vittata Wied. (23%), C. montana O. S. (16%) and C. wiedemanni Kröber (15%) for more than half the species of Chrysops (Table 11).

Entomologists interested in population dynamics have devoted considerable attention to the numbers of eggs laid by various species of insects, the mortality and non-viability of eggs, and mortality in young larvae; but there is another aspect of the problem which has received less attention than it deserves. This is the necessity for females to place their eggs sufficiently close to an adequate supply of food to insure the growth and development of the F, generation. Fulfillment of this requirement is particularly important for those species whose larvae are restricted feeders, that is, monophagous or oligophagous. It is generally assumed that the continued existence of a species is evidence that the eggs are always properly placed. As a consequence of this assumption very few quantitative studies have been undertaken, with the result that the contribution of the adult's behaviour to the degree of survival in larval populations is unknown. The following field studies were undertaken to supply some information on this score.

In June, 1954, the alfalfa weevil, Hypera postica (Gyll.), was found in very small numbers (one per 500 sweeps) in alfalfa fields in the valley of the Milk River and in the area between the hamlets of Onefour and Orion in southeastern Alberta. These were the first records of its occurrence in Canada. As the host-specific parasite Bathyplectes curculionis (Thoms.) (Townes and Townes, 1951) emerged from some of the weevil larvae collected then, the weevil had been in Alberta for at least one year. On July 26 an intensive search was made in the irrigated areas around Lethbridge. Only two weevils were taken in approximately 25,000 sweeps from 25 fields. The distribution of the weevil at this time indicated that it had migrated from the irrigated areas of Montana that lie along the lower reaches of the Milk River by way of the river valley.

Recent rearings of the geometrid Melanolophia imitata (Wlk.) by officers of the Vernon and Victoria, B.C., laboratories of the Forest Biology Division, Canada Department of Agriculture, have yielded a series of a new species of Casinaria for which the following description is offered.

Casinaria melanolophiae, new species

Female. Length 7 mm. Head thin, temple rather weakly receding for a considerable distance behind eye, and beyond rather strongly rounded to occiput; antenna with 29-31 segments, the shortest flagellar segments at least a little longer than broad; cheek short, about 0.30 breadth of base of mandible; ocelli large; greatest diameter of lateral ocellus twice as great as ocellocular space and three-fourths as great as post-ocellar line; head and thorax dullish, with granular sculpture; mesoscutum and scutellum densely, shallowly punctate, with punctures somewhat obscured by granular sculpture; sides of thorax finely granular and with only a few minute punctures; propodeum and abdomen as in C. semiothisae Wly.

Since 1946, a major project at the Vineland Station laboratory has been one on the indirect effects of pesticides on populations of injurious arthropods in peach orchards of the Niagara Peninsula. Plant-feeding mites have been the most readily affected. This paper describes the gross changes in mite populations produced by the pesticides and considers their economic importance and the possibility of reducing their injurious effects. The controversial problem of the means whereby some pesticides, particularly DDT, promote mite increase is still under study and will be treated in later papers.

In a survey of infestation by the European corn borer, Ostrinia nubilatis (Hbn.), in Essex County, Ontario, in 1957, officers of the Chatham laboratory found several hymenopterous pupae associated with dead borers. Adults emerged in the laboratory and were identified by Mr. G. S. Walley, Entomology Division, Ottawa, as of Horogenes punctorius (Roman), an imported parasite of the borer. This is the first record of its establishment in Canada.

It is generally agreed that insects whose larvae feed on plants do not increase to the larval food limit except in sporadic and unusual cases. In the few detailed studies which have been made, as, for example, Varley's (1947) study of the knapweed gallfly, the evidence suggests that the insects are held in check by parasites and predators. Andrewartha and Birch (1954) are of the opinion that shortage of food is probably the least important factor in limiting the numbers of animals in a natural population. On the other hand, they have pointed out (p. 489) that while it is unusual for an extensive population to consume all or most of the stock of food in its area, it does not follow that the amount of food is rarely of major importance in determining the numbers of a natural population. Several examples (p. 492) were given in which shortage of food was chiefly responsible for failure of population increase even though the absolute supply seemed adequate. In these cases local supplies were exhausted and the chance of finding fresh supplies depended upon the distribution and abundance of food and the powers of dispersal of the animals. In other words, the food was inaccessible relative to the animals' capacities for dispersal and searching.

Aphidecta obliterata (L.) is a common predator on conifer-infesting adelgids and aphids in Western Europe, including Scandinavia and the British Isles (Wylie, 1958b). The life cycle in Europe and descriptions of the various stages have been published (Weise, 1892; Portevin, 1931; Van Emden, 1949; Van Dinther, 1951; Wylie, 1958a). Beginning in 1941 several attempts have been made to introduce this species into Eastern Canada against the balsam woolly aphid, Adelges piceae (Ratz.). The initial liberations from England and Germany were apparently unsuccessful due to the inability of the insect to survive the Canadian winter conditions. Later collections were made in Sweden, Czechoslovakia, and Switzerland (Table I) from areas where the winter conditions more closely resemble those in Canada. These liberations also proved unsuccessful. The present paper brings together all available information on the liberations and related experiments olbtained during the liberation years.