It is universally recognized that the spatial distribution or pattern of animals and plants in nature is neither uniform nor truly random. In order to study a biological community quantitatively, or to assess the densities of living organisms in their habitats, ecologists have found it profitable to sample the space in which the organisms occur. The distribution of the number of individuals per sample is of fundamental importance.

A midge, Contarinia oregonensis, is one of a number of species of insects which causc seed losses in Douglas fir, Pseudotsuga menziesii (Mirb.) Franco. In recent years it has been reported causing more damage than any other single species of Douglas-fir cone insect in western Washington (Johnson and Heikkkenen. 1958). This has been the situation on Vancouver Island also.

The species bas described by Foote (1956) from specimens taken in Oregon in 1916.

The name Syneta is usually attributed to Lacordaire, who was the first to publish it with a description (1845, Mém. Soc. Roy. Sci. Liége 3:226). It has also been attributed to Dejean, for it first appeared in the third edition of his Catalogue des Coléoptères (1837, p. 385) where it is ascribed to Eschscholtz. Barber and Bridwell (1940, Bull. Brooklyn Ent. Soc. 35: 1–12) showed that such names were often validated by publication in the Dejean Catalog and that the chrysomelid names validated there should be attributed to Dejean, except those ascribed there to Chevrolat.

The principal insects that attack toadflax (Linaria vulgaris Mill.) in Canada are Brachypterolus pulicarius (L.), a flower-eating nitidulid, and Gymnaetron antirrhini (Payk.), a seed-eating weevil. B. pulicarius was found in 1953 in all provinces of Canada but G. antirrhini was apparently absent from Saskatchewan and Alberta, the two provinces where the spread of toadflax was causing alarm. Thus the seriousness of the toadflax seemed to be related to the absence of G. antirrhini. In an artempt to correct this situation Smith (1959) collected 4,000 adult G. antirrhini and released them in mid-July, 1957, at Marsden, Saskatchewan, and Codesa, Alberta. However, it now appears that the rapid spread of toadflax occurred in the absence of B. pulicarius and that this beetle is more valuable than first thought. This paper discusses the role of B. pulicarius and the results of introducing G. antirrhini.

This study was originally undertaken so as to provide information on the life history and ecology of Tarsonemoides truncatus (Ewing), to describe for the first time the developmental instars and male, and to redescribe the female of this species. Research soon indicated, however, that a group of closely related species of mites, including T. truncatus, was involved and that the problems to be investigated were more complex and extensive than anticipated.

Hille Ris Lambers (1960) erected the genus Toxopterella for his new species, canadensis, collected in Ontario and New Brunswick from Crataegus. At that time he had seen only the alate form of the species from Sorbus described herein, not the fundatrix, which is almost indistinguishable from the fundatrix of Toxopterella canadensis H.R.L. Because of the similarities in the fundatrices and because of the unique characters that they have in common in this morph, we place the aphid from Sorbus in the genus Toxopterella H.R.L., 1960. But the alatae of the two species are distinctly different and we therefore place this species from Sorbus in a new subgenus Sorbobium.

Aptesis biasizona (Grav.) is a common and widely distributed parasite of diprionid sawflies in central, western, and northern Europe, with parasitism varying from three to 90 per cent on different hosts and in different areas. One of these sawflies, Neodiprion sertifer (Geoff.), is very commonly attacked, with parasitism of 30 to 80 per cent in Czechoslovakia, 10 to 52 per cent in Hungary, and 17.5 to 40 per cent in Sweden (Morris et al., 1937).

In November, 1957, several specimens of adult beetles were collected from beaver pelts taken in the Lake George area of New Brunswick by a local trapper, Mr. Donald Millican. These were referred to me and were later identified as Leptinillus validus (Horn), an ectoparasite of the beaver, Castor canadensis Kuhl, by Mr. W. J. Brown of the Entomology Research Institute, Ottawa. This is the first record of the species having been found in New Brunswick.

The lamiine genus Hyperplatys Haldeman is represented in Eastern Canada by two species, H. maculata Hald. and H. aspersa (Say). Both are small grevish long-horned beetles with spotted elytra. These species have suffered from considerable taxonomic confusion, having been misdetermined by Blatchley (1910), Felt (1924), Knull (1946), and probably a number of other authors. Craighead (1923) described the larva and pupa of H. asperus Say (sic), but apparently this was also a misdetermination, since his pupal description obviously refers to H. maculata.

This bumblebee is rather common in southeastern Brazil, northern Argentina, and in parts of western South America. However, no detailed specific data have yet been published on its biology or nesting habits.

On November 5, 1955, while searching for bumblebees in Brazil, the writer succeeded in finding a newly established nest of this species about one-fourth mile from rhe coast in Parana, north of Guaratuba near Praia de Leste, some eight miles south of Matinhos. The coastal terrain at that location is somewhat irregular, not exceeding fifty feet in elevation and covered, for the most part, with rather dense, low woody vegetation. Near mid-day, from a vantage point at the side of the only north-south road, I spotted a queen in low direct flight toward a clump of shrubs growing about fifty feet to the west, where she suddenly vanished upon reaching that point. This behaviour instantly meant one of two possibilities–either she had stopped to visit flowers, or she had entered her nest close by.

During a stay at the Research Station, Canada Department of Agriculture at Kentville, Nova Scotia, from July 3 to October 16, 1959, I had the opportunity to make some observations on the natural enemies of the woolly apple aphid, Eriosoma lanigerum (Hausm.), the rosy apple aphid, Dysaphis plantaginea (Pass.), and the green apple aplud, Aphis pomi Deg. An inventory of these enemies was made in the Annapolis Valley in apple orchards. sprayed according to the principles of the spray schedule of Dr. A. D. Pickett. This schedule avoids spraying with fungicides and insecticides such as sulphur and phosphorus compounds, which are very harmful to the enemies of a number of pests, studied by Dr. Picktett and his staff (cf. Pickett 1959). The dipterous predators and their enemies are dealt with in this paper.

The maggot complex of Hylemya a cilicrura (Rond.) and H. liturata (Meig.) attacked flue-cured tobacco transplants in southwestern Ontario in increasing numbers from 1958 to 1960. Previously they had been of very minor importance to tobacco in this area.

Resistance was suspected near Delhi, in Norfolk County, when abnormal infestations developed in soil treated with aldrin or heptachlor. Planting-water treatments of aldrin, dieldrin, heptachlor, or lindane also failed to give appreciable control. Similar increases in house-fly populations, coincidental with decreased susceptibility to chlorinated hydrocarbon insecticides, have been noted (2).

Through the kindness of Dr. E. W. Baker of the Entomology Research Division, U.S. Department of Agriculture, and Dr. J. F. G. Clarke of the U.S. National Museum, Smithsonian Institution, I was provided with a number of mites of the family Cheyletidae. Among these were specimens of two new species representing a new genus, and a new species of Cheletominus Oudemans, formerly monotypic.

In a previous paper (16) an account was given of the relative efficiency of dry deposits of Diazinon [0,0-diethyl 0-(2 isopropyl-4-methyl-6-pyrimidyl) phosphorodithioate], Trithion [0,0-diethyl S-(p-chlorophenylthiomethyl) phosphorodithioate] and Sevin[l-naphthyl N-methylcarbarnate] in preventing the reinfestation of apple trees by the apple aphid, Aphis pomi DeG. In those experiments no comparison was made of the initial effectiveness of the insecticides in killing aphids by direct contact while the spray deposits were still liquid. Instead, interest was concentrated on the relative progress of recolonization of aphid-free trees, by aphids, as a measure of the effectiveness of dried and aging deposits. In the work reported here the results of similar investigations on two further aphicides are described.

Agria [= Pseudosarcophaga] affinis (Fall.) and Aphaereta pallipes (Say) make an excellent host-parasitoid couple for a determination of effects of host diet on a parasitoid. The anatomy, life history, and behaviour of these insects have been described (Salkeld, 1959; Coppel et al., 1959). Moreover, A. affinis can be reared axenically on chemically defined diets and it is readily attacked in the laboratory by A. pallipes, a parasitoid of the onion maggot, Hylemya antiqua (Meig.). This parasitoid deposits eggs into the body cavity of its host and these increase in size: the duration of the egg stage depends on the age of the host larva when parasitized (Salkeld, 1959).

Distinguished from the common ‘cluster fly’, Pollenia rudis (Fab.) as follows: Mesonotum with a median stripe anterior to transverse suture (readily seen with naked eye in oblique posterior view). Basicosta black (in rudis it is reddish-brown in female but inclined to be darker in male especially towards the base). Tessellation of abdomen less broken, the contrasting pollinose areas larger and more regular (rectangular) in outline. Abdominal pollen cinereous with bluish reflection (dull yellowish in rudis). Male genitalia (Figs. 1-3) with forceps and aedeagus longer and more slender.

The Essex skipper, Thymelicus (Adopaea) lineola (Ochs.), is said to have been introduced from Europe to the area of London, Ontario, about 1910 but attracted Iittie attention until 1955 (MacNay, 1956). Since then it has been found over most of southern Ontario (MacNay, 1959) and presently is causing damage to fields of timothy, Phleum pratense L., near Priceville, Ontario. As the larvae eat the leaves of timothy and orchard grass, Dactylis glomerata L., this species is a potential pest of forage crops.

The genus Ips in North America contains several groups of closely related species which are at present poorly defined. Morphological characters alone do not provide an adequate basis for deciding whether some of the forms are specifically distinct or represent mere variations which may occur in the same general locality or even in the same brood. The extent of this variation can be determined only by breeding isolated pairs through successive generations combined with biological studies in the field. The present article describes techniques for rearing successive generations of Ips in the laboratory.

Near Belleville, Ontario, it was necessary to take quantitative samples of predators in shallow pools in field studies of the natural control of mosquitoes. To expedite this work a light-weight sampling cage was constructed. Its description follows.

The cage (Fig. 1, top) consists of an enclosure (A) and two sorting trays (B and C). The enclosure, covering one-half square metre, is of four screened frames, each 12 inches high. Each frame is of aluminum extrusions (Higgins-Homeshield Limited, Toronto, Ontario) of the types shown in details F and G. The extended flange on extrusion G, used at the right-hand side of each frame, provides a means of overlapping and fastening at the comers of the enclosure. After the frames are fastened together to form a square, pointed angle-aluminum legs (D) 16 inches long are fastened to each inside corner. Small braces are alio fastened across each corner to hold the enclosure in shape.