The possibilities of using genetic principles to improve biotic agents used in biological control are discussed, and a number of examples quoted where possibly useful racial differences between parasites occur.

However, the main conclusion is that in introductions of biotic agents the principal aim should be to have as much genetic variability as possible in the material released, rather than to try and select a priori certain apparently suitable strains.

Comparisons of ecologic communities are often limited to presentations of frequency lists in tabular or bar-graph form. Kendall's “Tau” coefficient is appropriate as a measure of rank correlation between such numerical profiles. A special problem arises where species in one community are absent from the other. Such species may either be assigned zero frequency and last-place ranking in the community where they are absent, or they may be dropped from both rankings, depending on which method yields the more conservative correlation. Tau has the same limits (± 1) as the familiar product-moment correlation coefficient. Moreover, as a nonparametric statistic it is free of considerations of distribution. Comparisons between soil-fauna communities from the Quetico-Superior forest area are used to illustrate the method. The problems of tied rankings, variance and significance of Tau, confidence limits for Tau, and the significance of a difference between Tau coefficients, are also considered.

In its territorial behavior, the “tricolor” form of Hetaerina titia differs markedly from both typical H. titia and H. americana. Territoriality between “tricolor” and americana males is initiated only by the latter, and affects the spatial structure of a breeding population of “tricolor” males. Territoriality between americana and typical titia is initiated by either species, and usually leads to displacement of the americana male; this has no visible effect however on the population structure of americana.

H. titia and the “tricolor” form are suggested as separate species because of: (1) differences in breeding and territorial behavior (in both intra- and interspecific flights), and differential habitat selection by females for opposition. (2) existence of different and consistent female body color patterns and the breeding of these females with their specific male type. (3) the strong likelihood that the male wing color patterns are genetically governed with the implication that genes are not interchanged between titia and “tricolor”.

Many species in the genus Andrena have been described from one sex only. During studies of this genus in Ontario, the authors have associated the males of four species with the appropriate females. The males of Andrena (Trachandrena) alleghaniensis Viereck, A. (Leucandrena) chippewaensis Mitchell, A. (Conandrena) rufosignata Cockerell and A. (Gonandrena) dreisbachi Mitchell, all previously unknown, are described in this paper.

Tetranychus sinhai Baker (Acarina, Tetranychidae), a new pest was observed to infest barley, wheat, and rye crops in the Prairie Provinces of Canada. In barley, typical symptoms of the mite attack are manifested by a darkening of leaves, followed by yellowing and wilting from the bend of the leaf to its tip. The increase in number of mites per leaf was reflected by the showing of advanced symptoms on leaves. One hundred and sixty-five barley varieties from different parts of the world were examined for their reaction to T. sinhai infestation in the field. Of these 15 were found to be resistant, 47 moderately resistant, 88 moderately susceptible, and 15 susceptible. In general, the barley varieties grown in arid regions of the world appeared to be more resistant to T. sinhai infestation.

The most commonly grown barley varieties in Canada, Parkland, and Montcalm, were moderately susceptible. Only two North American varieties, Canadian Lake Shore–C.I. 2750, and Gem C.I. 7243 showed high resistance to T. sinhai infestation.

The fourteen species of the subgenus Eurylophella are reviewed with accounts of each species including complete synonymies, synoptic descriptions of nymphs and adults, and distribution. Illustrated keys for nymphs and adults and distribution maps are presented for each species. Ephemerella bieoloroides McDunnough is regarded as a synonym of E. verisimilis McDunnough. Ephemerella doris and E. trilineata Berner are of questionable status, being either closely allied to or identical with E. temporalis; and the relationship of E. lithuanica Kazlauskas to E. karelica is uncertain.

The ambrosia beetle, Trypodendron lineatum (Oliv.), causes extensive damage to logs in coastal British Columbia. The logging debris or slash felled in the autumn has been found to be an important breeding place for these beetles. The shaded sides of the larger pieces of slash sustained the greatest attacks and produced the most brood. The population increased about four-fold as a result of breeding in slash and this increase was estimated to be more than one quarter of a million beetles per acre on the areas investigated. A very large population of these beetles can develop each year in districts where autumn and winter felling is in progress.

Four species of Orius Wolff, a Holarctic genus, are known from the Nearctic region. Orius insidiosus (Say) is known from midwestern and eastern United States and eastern Canada, while O. tristicolor (White), shown here to be a valid species, is transcontinental in North America. O. minutus (L.), a common species in the Palaearctic region, is known from western North America. O. pumilio (Champ.) occurs in Florida. The distinguishing characteristics of the species are given, and a key is provided.

Descriptions of alate viviparous female, ovipara and male of Pseudocercidis rosae Richards are given, with brief notes on biology of the species on Rosa sp.

Three insecticides — lindane, dieldrin, and Sevin — were tested for control of the Douglas-fir cone midge, Contarinia oregonensis Foote (Diptera: Cecidomyiidae). They were applied to infested duff samples at the rate of 1.5 pounds of insecticide in 15 gallons of diesel oil per acre. Lindane was the most effective, causing a 98.5% reduction in the number of midges emerging from the duff. Dieldrin also caused a significant reduction in emergence, but Sevin was no more effective than diesel oil alone.

The results of this test suggest that oil-based sprays applied to the duff before the cone midges emerge might give satisfactory control more consistently than the water-based sprays which are usually applied to the trees. The test procedure would avoid the timing and formulation problems involved in treating developing cones on the trees.

The taxonomic status, life history, distribution and hosts of Bessa harveyi (Tnsd.) are discussed. In its development on the larch sawfly, Pristiphora erichsonii (Htg.), a partial second generation of parasite adults emerges after the host larvae have completed feeding. Alternate hosts are scarce and rarely parasitized so that there is little or no successful reproduction by these adults.

In Gatineau Park near Ottawa Simulium venustum adults were present in appreciable numbers around man (usually 20-100 flies/man/hr.) only between mid-May and mid-June in 1958-60, numbers after late June being negligible apparently because a succeeding generation failed to mature in significant quantity. It is suggested that differences in the duration of the S. venustum biting problem in different parts of eastern Canada largely depend on whether or not streams remain suitable for the aquatic stages after the spring generation derived from overwintered eggs has emerged.

In sweep-net catches of flies attracted to man at fixed sites the proportion of parous flies was nil in mid-May and increased to near 100 per cent by mid-June, 3 change sometimes interrupted by the appearance of a second wave of nulliparous individuals from late fly-producing streams. The latter were anatomically indistinguishable from flies produced earlier apart from reduced body size. The results suggest that the populations studied were anautogenous and that there was no deviation from this condition that could be attributed to variations in the food available for larvae in different streams or at different times.

The proportion of attracted parous flies containing relict eggs sometimes tended to increase towards the end of the season, suggesting that a large proportion of the few flies still remaining had completed two or more ovarian cycles.

Parous flies tended to be particularly active in late afternoon and evening but instances when this diurnal pattern did not occur were observed.

Laboratory tests were carried out to determine if certain types of cover and surfaces were preferred by adults of Hypolithus bicolor Eschscholtz. Approximately 45% of the adults selected the rough stone when a rough stone, a smooth stone, a lump of dried manure and a square of paper were provided simultaneously as cover. Soil moisture did not seem to influence this selection, except that the cover in the soil at the highest moisture level was rejected. The selection of preferred cover appears to be in response to thigmo-kinesis coupled with a tendency of beetles to congregate in tight groups under the cover.