In a recent paper, Pointing (8) described the distribution of the European pine shoot moth, Rhyacionia buoliana (Schiff.), in Ontario. Since first discovered in the Toronto area in 1925, the insect has become widely dispersed, so that at the present time, it appears in almost continuous distribution wherever red and Scots pines grow in southwestern Ontario. Two main factors are responsible for the rapid spread of the infestations, (a) the chance planting of infested nursery stock, and (b) the natural dispersal tendencies of the species. This, and the succeeding paper of this series, will be concerned with the natural dispersal of the shoot moth; dispersal, as used throughout both papers, describing movement beyond the tree on which the insect hatched from the egg.

Many authors noted the attraction of the males of several species of mosquitoes to sound (references summarized by Roth, 1948). The frequencies of sound to which the males respond were investigated by Roth (1948) and the frequencies and intensities by Wishart and Riordan (1959). Tischner (1953) applied electrophysiological methods to the reception of sound in the male of Anopheles subpictus Grassi and advanced a theory to explain the ability of the male of this species to orient itself toward the sound source. In his theory he dismissed the use of phase differences between the two receptors because of the relatively small distance between the two antennae and concluded that each is capable of functioning alone by detecting the relationship bemeen the fundamental and the second harmonic in the microplionics produced by the Johnston's organ. He did not demonstrate this by behaviour experiments nor, do we believe, did he produce sufficient electrophysiological evidence. The present paper is a further examination of this subject in the mosquito Aedes aegypti (L.), in an attempt to reconcile the data from electrophysiological experiments with those of behaviour in an explanation of the orientation of male mosquitoes towards sound.

In work on responses of insects to sound at Belleville, by Mr. G. Wishart, a mechanical device was needed to provide a means of slowly revolving a pair of directional light-traps in a horizontal plane on the circumference of a circle 20 feet in diameter. One of the traps was to be used as an experimental trap and the other as a check against the results of the first. A machine was designed, constructed, and put into operation in July, 1961.

The three new species described here were discovered in recent years in the course of forest aphid studies in central Canada.

Measurements used in this paper are in millimetres. The number of specimens of each form of the aphid measured is shown and the range of measurements given in parentheses. The single measurement preceding the parentheses is not an average, but refers to a single representative specimen.

This work supplements that of MacKay (1959), and includes the descriptions and illustrations of the larvae of ten species, and notes on two genera and the colour variations of two species. The subfamily ‘Olethreutinae’ has been substituted for the ‘Olethreutidae’ of MacKay (1959) in the title of the paper; this conforms with the adult studies of Obraztsov (1945), Diakanoff (1952) and other authors.

Morgan and Anderson (1957) discussed in detail the synonymy of the Bryobia praetiosa Koch complex. They raised the apple inhabiting form to species status, and gave it the name, brown mite, Bryobia arborea.

The brown mite from apple trees in Nova Scotia was examined by C. V. G. Morgan, Summerland, British Columbia, and found to be morphologically similar to the B. arborea on apple in British Columbia. It is possible, however, that the Nova Scotian form may be a geographical race.

In 1958, intensive studies on the population dynamics of the imported cabbageworm, Pieris rapae (L.), on cabbage were initiated in long-term study plots at Merivale, Ontario. The object was to construct ecological life tables for successive generations of the species, and ultimately, to develop mathematical models describing survival of field populations. This paper reports on the variation between samples of immature stages of the insect, and between some of the mortality factors affecting its abundance; it further illustrates the use of these data in designing a sampling plan with acceptable limits of precision.

Any continuous or undivided sclerotized plate of the exoskeleton is known as a sclerite and when two sclerites are contiguous the line of junction or demarcation is commonly known as a suture. Sutures in this accepted sense are of three kinds. The most common is a depressed line at the bottom of a shallow furrow or sulcus which marks the position of an internal strengthening ridge. The ridge may be formed in tnro ways.

An aerial spray program was conducted by the District of Kitimat, B.C. on August 1, 1960 for the control of the saddle-backed looper, Ectropis crepuscularia Schiff. An oil formulated DDT spray (1/2 pound technical DDT per U.S. gallon), was applied by aircraft at a rate of 1 gallon per acre. The results were inconclusive and raised the questions as to whether the low insect mortality counts were due to inadequate spray coverage or to the relative low susceptibility of the larvae to the DDT formulation. (Silver, 1961).

The black cutworm, Agrotis ipsilon (Hufnagel), is of major economic importance in many areas of the world. In recent years, adequate methods for assessing the toxicity of insecticides to the black cutworm have been developed (Begg and Harris, 1958; Begg et al., in preparation; Harris and Mazurek, 1961). However, with the exception of the works by Crumb (1929) and Satterthwait (1933), less research has been devoted to the life history of this insect.

The flight of bark beetles covers a short but important period of their life cycle, during which they are exposed to conditions not encountered during the major portion of their life under the bark. The time of flight and the factors which affect it are important, not only to the dispersal and survival of the insect, but also in the interpretation of experimental data dependent upon the beetle's flight activity.

Chapman (1954), Rudinsky and Vité (1956), and Atkins (1959, 1960, 1961) studied the flight of the Douglas-fir beetle under laboratory conditions, but there is scant reference to field studies on the flight of this insect. Chapman and Kinghorn (1958) recorded the number caught in window flight traps near Cowichan Lake, B.C., and unpublished reports describe emergence records obtained from cage studies conducted near Lumby, B.C.

In the first paper of this series (3), the factors affecting flight, and the flight potential of egg-laden females of the European pine shoot moth, Rhyacionia buoliona (Schiff.), were discussed. It was shown that the adults are relatively strong fliers, with a potential flight range greater than indicated in much of the earlier literature. It was also pointed out that natural dispersal of this species is dependent upon flight and subsequent oviposition by gravid females because unmated females seldom fly, and little, if any, population dispersal occurs through the long range movements of early instars drifting on silk. This final paper of the series deals with field studies designed to obtain information concerning the dispersal tendencies of gravid females under natural field conditions.

The Royal Society Expedition to southern Chile, 1958-59, was concerned with a study of the area known as Archiplata (Kuschel, 1960), the southwest part of South America which formed an isolated land mass in the Tertiary and which is the part of the Neotropical region showing affinities with New Zealand, Australia, South Africa, the islands of the South Pacific, Atlantic and Indian Oceans, and the Juan Fernandez Islands.

In a recent study of scale insects of the genus Pulvinaria in the peach growing areas of southern Ontario, four species were identified: P. vitis (L.), P. innumerabilis (Rathvon), P. acericola (Walsh and Riky), and P. floccifera (Westwood). Of these, only the first two, P. vitis and P. innumerabilis, were abundant enough to be of economic importance and because they resemble one another, especially when the ovisac is present, they may easily be confused.

Recent laboratory studies have shown that the type of spatial distribution of a host or prey population may affect the degree of natural control exerted by parasites and predators. For example, Burnett (1958) showed that the rate of paratisitism of the greenhouse whitefly, Trialeurodes vaporarium (Westw.), by Encarsia formosa Gahan, was considerably greater when the hosts were aggregated than when regularly distributed. In this case, searching parasites were better able to find groups of hosts than isolated ones. Similar results have been obtained by Huffaker (1958) in experiments with a predatory mite, Typhlodroms occidentalis Nesbitt, and a phytophagous mite, Eotetranychus sexmaculatus (Riley). Other important effects of aggregation are evident in the growing literature on this subject, as exemplified by the work of Long (1955), Mizuta (1960), and Morimoto (1960), who showed that the rate of development of some lepidopterous larvae in groups is greater than that of isolated larvae.

The varied interpretations by numerous biologists, of the role of predation in population dynamics have been critically reviewed by Holling (1959) and by Huffaker and Kennett (1956). They conclude that the processes of predation may serve to regulate prey density and disagree with generalizations that minimize the role of predation. This role has been a subject of considerable interest in recent years, notable contributions being the laboratory investigations of Collyer (1958) and Huffaker (1958), and the field studics of Holling (1959).

In Saskatchewan the migratory grasshopper, Melanoplus bilituratus (Wlk.), is most numerous in areas of cultivation; within these areas weedy grain fields seem to be its most favored habitat. On native grasslands where this grasshopper is less prevalent, it favors overgrazed pastures in which palatable forbs and weed species are common.

The relationship of M. bilituratus to its food plants has been reported by a number of workers in various parts of Canada and the United States (Pfadt, 1949; Anderson and Wright, 1952; Smith et al., 1952; Barnes, 1955; Gangwere, 1956; Pickford, 1958; Scharff, 1961). Certain differences in food preferences and in reproductive potential of this grasshopper may be noted in these reports. Some of the differences may have occurred because bilituratus (mexicanus auth. in part) is made up of a number of sub-species and local populations (Brooks, 1958; Gurney and Brooks, 1959).

This paper offers a taxonomic arrangement of the North American species of Chrysolina Motschulsky. Sixteen species and one subspecies are recognized. The species of the region were reviewed last by Van Dyke (1938, Bull. Brooklyn Ent. Soc. 33: 43-58), who recognized eight species and one subspecies. The arrangement offered below differs from the previous arrangement as follows. (1) Three species, caurina, finitima, and extorris, are described as new. (2) Two Siberian species, cavigera (J. Sahlb.) and magniceps (J. Sahlb.), are recorded from arctic Alaska; these have not been reported previously from North America, for American authors confused them with subsulcata (Mann.). (3) Included is one introduced European species, staphylaea (L.), that Van Dyke omitted. Also included are three European species recently introduced for control of the weed Hypericum perforatum L.; these are hyperici (Forst.), quadrigemina (Suffr.), and varians (Schall.). (4) C. blaisdelli Van Dyke and the subsequently described C. engelhardti Hatch (1939, Bull. Brooklyn Ent. Soc. 34: 49) are omitted, for they were transferred to Chrysomela by Brown (1956, Canadian Ent. 88: suppl. 3, p. 17). (5) One form, schaefferi new name (for auripennis cyanea Schaeffer, not Linnaeus), is elevated to specific rank. (6) One form, vidua (Rog.), is reduced to subspecific status under flavomarginata (Say).

The species described below is closely related to Dolichopus dorycerus Loew, 1864, but differs in both sexes in the colour of the lower orbital cilia and, in the male, in many details of the secondary sexual characters.

Dolichopus phyllocerus, new species

Male.–Length 6.3 mm.; wing length 6.2 mm. Face long, narrow, slightly broadened above, pale golden-brown, silvery below. Front metallic copper or coppery-green. Antenna (Fig. 1b) with first two segments yellow, the third black with about basal third yelllow; first segment of normal length; second very short, especially on lateral surface where it is scarcely visible; third short, broad, blunt. Arista black, about 21/2 times as long as rest of antenna, very slender, with a broad, blunt apical lamella. Lateral and lower orbital cilia yellow, upper cilia black.

The European pine shoot moth, Rhyacionia buoliana (Schiff.), was first discovered in North America on Long Island, New York, in 1914 (Busck, 1914). Since that time it has spread throughout most of the northeastern United States, becoming one of the most important insect pests of pine plantations. In Ontario, it was first discovered in the Toronto area (McLaine, 1926) and since that time has dispersed throughout southern Ontario, appearing regvlarly south of a line from the southern end of Gcorgian Bay to a point just east of Lake Ontario (Fig. 1). Isolated occurrences of the shoot moth have been reported north of this line but these have been short-lived on small plantation trees, or have persisted in cities and towns on ornamentals protected by snow cover during the winter. The continuous distribution of the insect has remained relatively static since 1951, and it appears that the northern limit of its range in Ontario has been reached.