In Eastern Canada, aphids cause serious losses in the potato crop–directly by injuring heavily infested plants and indirectly as vectors of viruses. A field study of factors affecting populations of potato aphids necessitates a method of estimating population that allows comparisons of results from different varieties of potato and from potatoes grown under different conditions. Davies (1934) described one of the first methods of estimating aphid populations in the field; he counted the aphids on lower leaves chosen at random, and expressed the opulation as aphids per 100 leaves. Simpson (1940) reported that the species of aphids on potatoes in Maine differed in their distribution on the plant; to obtain a better estimate of the population, he modified Davies' method and counted the aphids on equal numbers of leaves selected at random from the top, middle, and bottom portions of the plants. Other workers (Joyce, 1938; Hansen, 1941; Whitehead, 1943; Thomas and Jacob, 1943; Staniland, 1943; Jacob, 1944; Doncaster ana Gregory, 1948; Münster, 1948) used various methods of selecting leaves for the sample but continued to express the population as aphids per 100 leaves. Much of the earlier work was in the form of surveys to determine the population of aphids above which the maintenance of healthy seed stock was not a practical proposition.

The community of Fort Erie, Ontario, and the waterfront zone of Buffalo, New York, form one of the many areas in the St. Lawrence River drainage system that are annually infested by large numbers of adult Trichoptera and, to a lesser degree, Ephemerida. Betten (1934) reported on a field study, conducted in 1906, of the Trichoptera found at Buffalo, N.Y. He noted the prevalent species and the extent of the problem chat the insects create for the local inhabitants. The medical aspect was investigated by Parlato (1929, 1930, 1932) and Osgood (1934). In August, 1950, an investigation of the scale, composition, and source of the trichopteran infestation and possible control measures was initiated at Fort Erie, Ontario.

In February, 1951, specimens of chrysanthemum stools received from a nurseryman near Sardis, British Columbia, were found to be injured by maggots. Examination showed dipterous larvae feeding in channels bored in the centres of the roots, crowns, and new shoots.

As available literature contained no reference to an insect having this habit in chrysanthemums, material was caged for rearing. Adults began emerging on March 17, and were determined by Mr. J. F. McAlpine, Systematic Entomology, Division of Entomology, Ottawa, as Psila nigricornis Meig. This was a new record for North America.

The frequent failure of parasite development beyong the immature stages during insectary rearing work often results in incomplete qualitative and quantitative data on insect parasites. Keys to the larval and pupal stages are therefore an extremely useful aid in completing the picture in a study of A parasite complex.

The following illustrated key makes it feasible to obtain reasonably accurate specific determinations of the puparia of the dipterous parasites of the spruce budworm, Choristoneura fumiferana Clem., that occur in Canada. The writer gratefully acknowledges the inspiration and co-operation of A. R. Brooks during the preliminary preparations for the key. The illustrations were executed by Miss M. MacKay (Figs. 1-14) and R. Sugden (Fig. 15). Each figure illustratis the following: (a) posterior aspect of a puparium showing the location of the stigmal plates and the anal aperture, and any protuberances that are present; (b) one stigmal place and the stigmal slits; (c) lateral aspect of the outline of a puparium.

In investigations on the life-history of the onion maggot at St. Jean, Que., in 1951, a few specimens of a dipterous predator were found in the rearing cages in the laboratory. They were feeding voraciously on the adults, destroying a colony of nearly 300 flies within two weeks.

Specimens were identified by Mr. A. R. Brooks, Systematic Entomology, Division of Entomology, Saskatoon, Sask., as Coenosia tigrina (F.). Mr. G. E. Shewell, Systematic Entomology, Division of Entomology, Ottawa, has stated that nothing is known in Canada about the life-history of this species, but that it is apparently well known as a predator in Europe and that B. M. Hobby has published a long list of species on which it preys, including many anthomyiids.

The long-held belief that grasshoppers are to a large extent omnivorous and, as Wolcott (1936) states, “like cows, feed on any kind of vegetation”, is slowly giving place to the view that they are much more restricted feeders. Their habit of nibbling at almost anything, particularly when they are present in large numbers, probably led to this erroneous concept. More recent work such as that of Rubtzov (1931), Criddle (1933), and Isely (1938, 1944, 1916) stresses the fact that many species of grasshopper confine their feeding to a group of related plants, and a few species to a single plant.

In 1946, the writer published a list of 482 species of Ichneumonoidea which included all representatives of this group contained in the University collection or which had been elsewhere recorded as occurring in Alberta. As a result of the continued generosity of Dr. H. K. Townes in naming locally collected material for us, we have, subsequently, made consistent efforts to obtain as complete a representation of the Alhertan species in this group as time and opportunity have permitted. It is now possible to add about 170 species to the former list.

In July, 1949, a single specimen of a casebearing coleopterous larva was found feeding on a strawberry leaf in a plantation at the southeastern end of Grand Lake, Queen's County, N.B. During June and July, 1950, about a dozen larvae were found throughdut this area, and a greater number in plantations on both sides of Washademoak Lake, which is southeast and roughly parallel to Grand Lake and about ten miles distant. During 1951 the species was again collected in these areas, and was found in large numbers about 15 miles southeast of Washademoak Lake in the Belleisle watershed. Here the infestation was so great that in one instance 565 larvae were collected with a sweeping net on 100 feet of strawberry row, or an average of five larvae per plant.