Hygro-receptive sensilla have been found on the antennae of fruit flies (1), spider beetles (2), cockroaches (3), wireworms (5), ticks (6), mealworm beetles (8), flour beetles (11), and body lice (16). Two types of antennal sensilla, the basiconic and the coeloconic, have been identified as hygro-receptors of the grasshoppers, Melanoplus differentialis (Thos.) and M. mexicanus mexicanus (Sauss.) (12, 13). This paper describes the antennal sensilla of Melanoplus bivittatus (Say) and discusses their function.

Carvalho and Southwood (1955) made a world revision of the Cyrtorhinus-Mecomma complex, and listed 11 species and three subspecies of Mecomma. Those reported from North America are: ambulans (Fall.), gilvipes (Stål), luctuosa (Prov.), luctuosa pacifica Carv. and South., antennata Van D., and mimetica Carv. and South.

In the present paper, Mecomma bradora, n.sp., is described from Quebec, and the distinguishing external and genitalic characters are given. Additional notes on the habits, morphology, and distribution of Mecomma mimetica are given, and the status of Mecomma dispar (Boheman) in North America is discussed.

Large numbers of each of the stages of the cabbage maggot, Hylemya brassicae (Bouché), are often required for studies on biology or on biological or chemical control of the insect. A method has been reported by Sherwood and Pond (1954) for maintaining a colony for more than a year. The method described herein enables mass rearing of eggs, larvae and pupae and easy separation of any stage.

The micro-organisms that accur in insects may be pathogenic, nonpathogenic, supposedly or actually beneficial, or casual invaders. The literature on the various aspects of the subject has become extensive (Buchner, 1953; Fraenkel, 1952; Shrewsbury and Barson, 1954a, 1954b; Steinhaus, 1946, 1949).

According to one of the popular ecological theories, populations are self-governing systems, which maintain themselves in existence by utilizing “density-dependent factors”, whose effect becomes more intense as the population increases and less intense as it decreases. This theory is connected with a mathematical model developed by V. A. Bailey and A.J. Nicholson, 1935, to represent the results of the interaction of predator and prey populations. According to the theory, as expressed verbally, a disturbance of the conditions of stability – the “steady state” – produces oscillations which tend to re-establish the stable conctition. In fact, however, when numbers are inserted in the equations, the population values, at the end of one or more cycles – which increase in amplitude if there are more than one – fall below unity, which, on a common sense view may be considered to mean the extermination of the prey, followed by that of its predator or parasite.

On the basis of anatomical and ecological differences, Morgan and Anderson (1957) and Anderson and Morgan (1958) divided the Bryobia praetiosa complex of British Columbia into two species; the brown mite, B. arborea M. & A., 1957, found exclusively on fruit trees, and the clover mite, B. praetiosa Koch, 1836, found chiefly on herbaceous plants and known more commonly as a household pea. Acarologists in Switzerland, The Netherlands, and Russia have separated the complex into a number of species principally on anatomical bases (Pritchard and Keifer, 1958). In a recent exhaustive treatise of the complex in Switzerland, Mathys (1957) proposed five species and four ‘forms’.

Aphids of the species described below were first seen by the author at Cowichan Lake, Vancouver Island, in 1956. Additional observations and collections were made in 1959 at several other locations in southern British Columbia.

The species is unique in that it is apparently the only one in the genus living on western hemlock, Tsuga heterophylla (Raf.) Sarg.

All measurements of the body and appendages are in millimetres.

The juniper berry mite, Trisetacus (Eriophyes) quadrisetus (Thomas), was unknown in Canada until 1956, when its occurrence was noted on Rocky Mountain juniper, Juniperus scopulorum Sarg., in the Tzouhalem Indian Reserve near Duncan on Vancouver Island, B.C.; it has not been found elsewhere in the Province (Fig. 1). Material was first submitted to the authors by Mr. W. G. Ziller, Forest Biology Laboratory, Victoria, B.C. Each year almost the entire crop of berries on the only two trees in the area is destroyed by the mite; these trees are 30 and 50 feet high. In 1956 and 1957, no normal berries were observed. In 1959, only four healthy berries were found amongst 715 examined from the two trees. Such a heavy infestation indicates that seed production by these trees was practically eliminated since feeding by the mite destroys the seed.

Trogoderma parabile, a Nearctic species, was first described by Beal in 1954. In 1956 he reported it as a fairly common pest of granaries in California. In 1957, E. A. R. Liscombe (personal communication) recovered all stages of T. parabile in large numbers from flour mills and feed warehouses in Southern Alberta. In 1958, Brooks reported it from Saskatoon, Saskatchewan, where it occurred in several feed mills and was found infesting grain samples stored in small envelopes in the Science Service building. These reports are the first records of T. parabile in Canada. A closely-related Eurasian species, Trogoderma granarium Everts, is a serious pest of stored cereal products in hot dry parts of the world and is well-established in some parts of the United States and the United Kingdom but is not found in Canada. T. parabile, however, can adapt itself to colder conditions and may become a pest of economic importance in some parts of Canada.

The statement of Criddle (1917) that grasshopper outbreaks are associated with periods of dry weather has been repeated by many authors, but a close relationship has never been demonstrated.

Parker (1933) showed that at six localities in the United States grasshopper outbreaks during the period 1915-1933 had been preceded by periods of two to four years when either rainfall had been below normal during May-June or temperature had been above normal during July-September. Similarly Smith (1954) concluded that between 1910 and 1953 outbreaks in Kansas had been preceded by two years of sub-normal rainfall. Parker's charts show that grasshopper outbreaks generally followed periods of hot weather, but the charts of both authors show that only about half the time did outbreaks follow periods of dry weather – a situation that could be largely due to chance.

MacCarthy (1956) calculated the correlation coefficients between weather factors and populations of M. bilituratus (Walker) in five large areas of Saskatchewan during the period 1943-1952. His tables show generally insignificant correlation with total precipitation and only with mean minimum monthlv temperature in June of the previous year was there significant correlation in all five areas.

The present investigation was undertaken in an attempt to determine whether a sufficiently close relationship between grasshopper populations and climate could be found for use in predicting grasshopper outbreaks.

The genera comprising the family Odiniidae (Hendel, 1922) will run to Agromyzidae in the key to families in Curran (1934), but are distinguished from this family by a number of important characters, notably the abdominal structure of the adult and the bucco-pharyngeal skeleton of the larva. Adult Odiniidae have five pregenital abdominal segments in both sexes. The sixth segment of the female is greatly reduced and largely hidden beneath the fifth, and the seventh is membranous and retractile. In Agromyzidae six well-developed pregenital segments are present and the seventh segment of the female is modified as a heavily-sclerotized non-retractile ovipositor. The odiniid larva (Figs. 2, 6.) has a mouth skeleton much like that of the more generalized saprophagous forms (e.g. Drosophila, Piophila, Lucilia) and in no way resembling the highly-specialized structure of Agromyzidae. Species of Odiniidae are pale grey or clay-yellow with the thorax and abdomen conspicuously mottled or vittate with dark brown. The wing is usually spotted, at least on the cross-veins, and the tibiae have a more or less evident preapical dorsal bristle. Because of the abdominal structure, Hennig (1938) considers them more closely related to Chamaemyiidae than to Agromyzidae. The immature stages have mostly been found living in the galleries of wood-boring Coleoptera and Lepidoptera but the adult of Turanodinia Stack, is reported to have been reared from egg-masses of Pseudococcus comstocki Kuw.

Bryobia lagodechiana Reck, 1953, was originally found on bedstraw, or cleavers, Galium sp., growing at an elevation of about 6,890 to 7,220 feet above sea level in the Lagodekhsky reserve of the Armenian S.S.R. (Reck, 1953; Bagdasarian, 1957). A mite believed, on the basis of illustrations and descriptions only, to be the same species was found by the author in one locality in the Okanagan Valley of British Columbia. It was first observed on June 6, 1958, when about 10 female mites were noticed feeding on common horsetail, Equisetum arvense L., growing at an elevation of 3,300 to 3,500 feet near Orofino Creek on Mount McCaig, known locally as Orofino Mountain. The site, which was partially shaded by fairly heavy stands of tall coniferous trees, was somewhat boggy, and would undoubtedly be flooded during the spring run-off of Orofino Creek. Luxurious pure stands of this horsetail are common in such sites and, except for moss, it is often the predominant plant in many creek-bottom areas. An additional 20 female mites were collected at the same site on June 12, 1958. No males, or immature stages, were seen on either date. This is the first record outside southern Russia of the occurrence of a mite closely resembling B. lagodechiana, and the first report of the occurrence of any species of Bryobia on plants of the family Equisetaceae. The slide-mounted specimens are in the Canadian National Collection.

Zoogeographic studies can be pursued in the laboratory or library, but far preferably should be largely based on careful, first-hand field work. A familiarlty with species in the field is a prerequisite to a thorough understanding of both their zoogeography and their systematics. Naturally, knowledge of the actual relationships of the species, and of the geology and geographical history of the areas involved, are also prerequisites to a complete understanding of the zoogeography of a group of insects.

At the Victoria laboratory a simple plastic cage was devised for rearing root weevil adults on whole attached strawberry leaflets. The cage (Fig. 1) was constructed from 10-dram plastic pill vials (Cunningham, Drug Stores Ltd., 1300 Douglas Street, Victoria, B.C.) having an inside diameter of one inch and length of three inches.

The bottom of the hard styrene plastic vial was cut off with a band saw and the top of the soft polyethylene piastic lid was cut out with a sharp knife. Bronze screening of 44 mesh (number 60, strainer cloth supplied by Hickman Tye Hardware Co., Ltd., 910 View Street, Victoria, B.C.) was fastened to the bottom of the vial and to the top of the lid by placing 1 ⅛-inch squares of the screen on an electric hot plate and pressing the plastic parts onto the wire. The hot wire melted the plastic and became imbedded in it, forming a strong bond. The screen was trimmed with small tin snips and ground smooth on a grindstone. To facilitate attachment to growing leaves, a hot glass rod was used to melt a notch in the rim of the vial opening and lid large enough to accommodate the leaf petiole. An insect-tight seal was formed around the petiole in the notch when the lid was turned slightly.