The development of strains or races of insects that are resistant to insecticides is a serious obstacle to the progress of chemical pest control. In many cases recommendations at first viewed as offering a permanent solution for an entomological problem have had to be abandoned within a very few years. Until the general relationships governing insccticidnl resistance are reduced to an orderly and understandable basis, the permanent soIution nf an insect pest control problem by chemical treatment is largelv an unjustifiable expectation.

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.

Two species of tartricid larvae, which were easily separated by appearance and by host, were reared by the author during the summer of 1951. Identification of adults showed that two species of Sparganothis had previously been associated with the name Sparganothis pettitana (Robinson). The true S. pettitana was identified by comparison of a series of male adults of both species with the illustration accompanying the original description (Robinson, 1869, Pl. IV) and with Type No. 7417 in the Brakenridge Clemens Memorial Collection at the Academy of Natural Sciences, Philadelphia, Pa.

In a previous paper on the Siphonaptera of Canada the writer (Holland, 1949b) summarized all available published and unpublished data up to December 31, 1946. One hundred and twenty-seven species and subspecies of fleas were recorded, of which 121 are believed to be endemic, and 6 introduced in historic times from the Palaearctic Region.

Studies since 1946 have drawn attention to the occurrence in Canada of a number of species not hitherto recorded. Some of these were new to science. The discoveries of some of the others could have been predicted with reasonable certainty, the species being known from areas immediately south of the International Boundary, on species of hosts known to occur in Canada. In other instances the captures occasioned some surprise, the Canadian records representing rather broad extensions of the known ranges. Some of this supplementary information has already been published (Holland, 1949a, 1950, 1951a, 1951b). In the present paper, seven additional species and subspecies are reported from Canada for the first time. In partial compensation for this, the total of Canadian species is reduced by the recognition of two synonyms.

The following descriptions of new species of black flies are based on material acquired from several sources in the Division of Entomology. The largest collections were made by field parties engaged in the Northern Insect Survey, a project commenced in 1947 and conducted by the Division in co-operation with the National Defence Research Board. Much of the simuliid material accumulated by this survey still remains to he examined and it will be several years before the valuable data on species distribution that it contains can be assembled into a form suitable for publication. Several collections of northern material have also been contributed by officers of the Household and Medical Entomology Unit. The rest of the material is the outcome of rnp own field studies in the Ottawa district, These studies, comnenced in 1949 and still continuing, are on a much smaller scale than the northern work and are designed chiefly to increase my knowledge of the group and to verify or supplement certain aspects of the work done by Twinn (1) in this area.

During the summer of 1950, Dr. I. O. Buss, Professor of Wildlife Managemenr, State College of Washington, made a study of the food habits and ecology of the upland plover, Bartramia longicauda (Bechstein), in the Duke River Meadow, five miles north of Burwash Landing, southwestern Yukon Territory (Buss, 1951). Periodical sweepings, at weekly intervals, were made through three transects of the meadow, indicated in this paper by stations 1, 2, and 3. It was from this source thar the collections of insects, including a large number of Diptera, were obtained. Because of the remoteness of the region from any other in which, to the best of our knowledge, insect collecting has been done, and because of the ecological data presented hy Dr. Buss, we feel that the publication of this annotated list of species is warranted.

For many years studies of cutworm bionomics and control, especially of pest species, have been carried on in the Prairie Provinces of Canada. During these studies a number of cutworm parasites and hyperparasites of the bombyliid genera Poecilanthrax Osten Sacken, Villa Lioy, and Hemipenther Loew have been encountered. These species do not appear to be important factors in the natural control of cutworms, for they cause from two to five per cent of the total parasitism. No detailed data are available on the life-history of any of the species.

At the time when the Entomological Society of Canada was founded, 88 years ago, the science of entomology was almost synonymous with systematics. I say almost synonymous, because important advances in the study of insect development and behaviour had already occurred and even economic entomology, which now absorbs nine-tenths of our professional effort, was already showing signs of growth. Nevertheless, the great names in entomology were still those of the systematists. The work of description and classification was still the most absorbing interest in the entomological field.

One of the problems arising from severe outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.), is the evaluation of the factors contributing to the decline of the host trees. An intensive study of the death and deterioration of balsam fir, Abies balsamea (L.) Mill., was carried out from 1946 to 1951 in the area southwest of Lake Nipigon in northwestern Ontario, where a severe spruce budworm outbreak was in progress.

Three species and one subspecies of fleas, all belonging to the Ceratophyllidae, are described and figured in this paper. One of the species, formerly known only from Siberia, and imperfectly described, is redescribed, and recorded from Yukon Territory. The remaining two species and the subspecies are believed to be new to science.

Since the publication of Whitehouse's Catalogue of the Odonata of Canada and Alaska (1) several papers on Canadian Odonata have appeared that have added to our knowledge of the composition and distribution of this order of insects in Canada. Two species have been added to the Canadian list, viz., Celithemis martha Wmsn. from Nova Scotia by Cook (2) and Somatochlora sahlbergi Trybom from the Mackenzie District N.W.T., by Walker (3). Cook adds also the following that are new to Nova Scotia: Enallagma cyathigerum Charp., Gomphus spicatus Hagen, G. ventricosus Walsh, Celithemis elisa Hagen, Libellula pulchella Drury, L. Lydia Drury and L. luctuosa Burm.; and one new to New Brunswick, Aeshna interrupta interrupta Walk. Walker (3) adds two to Labrador (Lestes disjunctus Selys and Libellula quadrimaculata L.), two to Manitoba (Somatochlora septentrionalis Hagen and Leucorrhinia patricia Walk.) and four to the Mackenzie District, N.W.T. (Lestes congener Hagen, Nehallenia irene Hagen, Somatochlora albicincta Burm. and Sympetrum obtrusum Hagen) besides Somatochlora sahlbergi, already mentioned. He also gives a list of 14 species from the Yukon Territory, from which only two species were previously known .

Only recently has serious taxonomic study of the genitalia of Membracidae been undertaken. Authors such as Fowler (1894-97), Van Duzee (1908), Funkhouser (1917) and Lawson (1922) made only cursory studies or objected to the dissection and treatment necessary for such a study. Caldwell's (1949) revision of the Ceresini based on male genitalia is the first paper of its kind for the Membracidae.

For many years the true members of the illibalis group (usually placed in the wastebasket genus Pyrausta) have been listed as two or three species, under the names gracilalis Hulst, illibalis Hübner, and arsalteulis Walker. I was considerably surprised, therefore, to find several additional species standing, for the most part unrecognized, in North American collections. A further species, haedulalis Hulst, was compared by its author to gracilalis, and was placed by McDunnough (1939) between gracilalis and illibalis; I have seen the badly damaged tvpe of haedulalis in the collection of Rutgers University, and am convinced ihat the species does not belong in the present group.

Reproduction in the Pseudococcidae is usually regarded as being predominantly, if not exclusively, bisexual, though Ferris (1950) has pointed out that within the family as defined by him males are known for only a small percentage of the species described to date. Detailed biological observations have been restricted to those members of considerable economic importance and in regard to reproductive habits there are few specific references in the literature. Hough (1922) in his account of the life history of the clover root mealybug Chnaurococcus trifolli (Forbes) Ferris, stated that no males were seen throughout the period of the observations. James (1937) made a comprehensive study of the reproduction of Planococcus citri (Risso) Ferris, Pseudococcus maritimus (Ehrh) Ferris, P. gahani Green, P. adonidum (Linn.) Ferris, and Trionymus peregrinus Green, and found that parthenogenesis did not occur in any of these species. This confirmed conclusions of earlier workers with Pl. citri (Schrader 1923, Sutherland 1932), and with P. gahani and Phenacoccus gossypii Twns & Ckll. (Basinger 1934). However, Myers (1932) reported parthenogenesis in some of his experiments with Pl. citri but his procedure of isolating females from the cultures after the second moult is clearly open to criticism.

It is difficult to obtain accurate records of the occurrence of bird-lice and especially those associating them with correctly identified hosts. For this reason it is considered the following records of bird-lice, taken from birds in Ontario, may be of interest and should be published.

The collections were made by the author and Messrs. A. A. Wood and D. A. Arnott and one or two other persons. The specimens are in the collection of the Dominion Entomological Laboratory, Chatham, Ontario.

Numerous methods of rearing grasshoppers under laboratory conditions have been described (Brett, 1947; Carothers, 1937; Haydak, 1942; Parker, 1930). One now used at the Belleville laboratom to provide hosts for small-scale propagation of parasites has been very satisfictory for the rearing of several species of Cyrtacanthacrinae and Oedipodinae. It most closely resembles rhe method described by Haydak (1942), but requires only one type of cage. The rearing is done in a room with a constant temperature of 24°C. and a relative humidity of 50-60 per cent. The method described is dependent upon the use of field-collected eggs.

The physiochemical properties of the blood of an animal are maintained in a close equilibrium conducive to the normal functioning of the organism. Disturbances in the physiological functian may result in characteristic changes in the blood. For example, the specific gravity of normal human blood, which averages about 1.060, may vary with age, sex, nutritive condition, and disease (Hawk, Oser. and Summerson, 1947). The reaction of blood to metabolic and pathological conditions is recognized by the medical profession as a valuable aid in diagnosis (Scudder, 1939). Changes have been shown in the specific gravity of human blood in pregnancy and cancer (Polowe, 1932; 1934). It has also been shown that haemorrhage is accompanied by a decline in the specific gravity (Richet, Brodin, and Saint-Girons, 19 18).

The formerly monotypic genus Mioctenopsylla Rothschild, 1922, was erected to accommodate an unusual ceratophyllid flea collected from nests of the kittiwake, Rissa tridactyla ssp., during the Norwegian Expedition to Novaya Zemlya in 1921. Although it could be assigned to Jordan's “Group C” of Ceratophyllus s. lat., this species, described as M. arctica Rothschild, differed in many remarkable ways from all other species and genera of the group. The spines of the pronatal ctenidium, large and deeply pigmented in all other Ceratophyllidae, are reduced in Mioctenopsylla to short, pale structures that could easily be overlooked (Fig. 7). Other characters of the genus not found elsewhere in the Ceratophyllidae include denticulate dorsal margins to the abdominal terga, numerous minute punctuations on the sterna, and narrow mid- and hind-coxae, as well as distinctive sexual features.

In this paper two new species of Chimarra (Philoptamidae) and five new species of Hydropsychidae are described. The majority of the new species are from western United States. Grateful acknowledgment is made to Dr. R. H. Beamer of the University of Kansas for sending me many of the specimens used in this paper. Unless otherwise designated types of the new species are in the collection of the author.

During September, 1950, 23,180 specimens of the European earwig, Forficula auricularia L., were collected in Vancouver, British Columbia, for the purpose of recovering the imported parasite Bigonicheta setipennis (Fall.). Great fluctuations were observed in the number of insects caught from day to day. This paper is an attempt to assess the role of various climatic factors in these fluctuations.