Hot spots may develop quickly in farm stored grain under Canadian winter conditions. Heavy infestations of mites, insects and fungi may accompany such hot spots (Stirrett and Arnott, 1933; Watters, 1955). Once the heating process is initiated, whatever its cause, it brings about a rapid deterioration of grain, tluough charring of kernels, and reduction of their germinability, and by providing optimum conditions for the growth and reproduction of storage fungi, insects and mites.

Over a century ago Peck (4) observed that open-growing stands of white pine, Pinus strobus L., were subjected to greater weevil damage than were those growing in mixture with, and shaded by, other tree species. This observation, which was later corroborated by Graham (2) and MacAloney (3), suggested possibilities of silvicultural control of the insect by means of plantation growing of white pine in various kinds of mixtures. The results of this work were recently assessed in a review paper by Belyea and Sullivan (1), who concluded that further silvicultural control measures be curtailed until the physical and biological requirements of the insect were defined in terms of measurable factors of the environment. Investigations were carried out (6, 7) to establish the conditions of temperature, light, and moisture favourable for feeding, copulation, and oviposition of the adults, and development of the larvae. The results indicated that P. strobi is well adjusted to the environmental conditions in open stands of white pine, but that the limitations imposed by weather on weevil oviposition might be a major factor contributing to the inability of the insect. to adapt readily to the climate of many shaded stands. The present paper is an attempt to assess the role of weather and the physical characteristics of white pine leaders, hereafter called leaders, in limiting the successful invasion, by the weevil, of white pine stands growing as partially suppressed, understory trees. Emphasis is placed on providing an understanding of the differences in the climate of weevil habitats, adult feeding and oviposition behaviour, and survival of weevil populations in exposed and shaded stands of white pine. In addition, records were obtained for the purpose of forecasting differences in both the timing and amount of such acts as oviposition and feeding in populations in the two habitats.

Microctonus aethiops (Nees) auctt. (Fig. 1) and Perilitus rutilus (Nees) are parasites of adult Sitona weevils in Europe. They were released in Canada as control agents of the sweetclover weevil, Sitona cylindricollis Fahr. (Fig. 2). The immature stages and biology of the species were studied as a prerequisite to attempts at biological control. A similar investigation of the braconid Pygostolus falcatus (Nees) was completed (Loan and Holdaway, 1961). Jackson (1928) described some aspects of the biology of P. rutilus, and additional data are given in the present paper.

A detailed morphological study of the immature stages of Contarinia pseudotsugae Condr., C. constricta Condr. and C. cuniculator Condr., along with their description, is presented in this paper. This work is based on examinations of several hundred larvae of each species, with numerous observations of larvae in the act of moulting and pupating which confirmed the morphological indications of three larval instars. Included also is a brief description of the galls associated with each midge species. Terminology used in the larval descriptions follows that of Möhn 1955.

The following descriptions and notes are based on Palaearctic material of Fanniinae in the U.S. National Museum, Washington, D.C., and on Indian material in the Canadian National Collection of Insects, Ottawa. One new species is described from Tunisia, one from India, two from Japan, and six from Szechuen province near the China-Tibet border in China. Special thanks are due Dr. R. H. Foote of the U.S. National Museum for making this material available to me.

Most of the species of plants in the arum family, Araceae, have their flowers arranged on a central spadix which is surrounded by an enveloping spathe. These floral mechanisms have been classified by Müller (1883). The simplest type, represented by the water-arum, Calla palustris, has the spadix fully exposed and the spathe held back from it. Secondly, there is the type in which the spadix is surrounded by the spathe and is only partly visible through the opening of the spathe, as represented by the skunk cabbage, Symplocarpus foetidus. Thirdly, there is the most elaborate arrangement, represented by the cuckoo pint, Arum maculatum. In this type the spathe surrounds the spadix and is constricted a short distance above its base to form a chamber surrounding the flowers which are concentrated at the base of the spadix. Thus there is formed a “pitfall mechanism” or “kettle trap” which entraps insects that have entered the spathe and ensures the pollination of the flowers by the insects (McLean and Ivimey-Cook, 1956; Müller, 1883).

In the prairie region of Western Canada certain species of bumble bees are the principal pollinators of red clover, Trifolium pratense L. (Hobbs, 1957). Certain bumble and leaf-cutter bees are the only effective pollinators of alfalfa, Medicago sativa L., in Western Canada (Hobbs and Lilly, 1954; Hobbs, 1956; Peck and Bolton, 1946; Stephen, 1955). Unfortunately, bumble and leaf-cutter bees are seldom very abundant.

Otto Schwarz described ten species of North American elaterids, two of which he placed in the new genus Euplastius (1903, 1903a and 1906). Several of these species are known only from the types, and none has been redescribed or studied adequately. Dr. J. W. Machatschke of the Deutsches Entomologisches Institut, Berlin, kindly loaned type material of seven of these. Conclusions based on a study of these are summarized as follows:

Chalcolepidius substriatus Schwarz – Synonym of C. webbii LeConte.

The literature on the Hydracarina, or water mites, especially on the North American fauna, is widely scattered in many journals. The papers of Koenike (1895 and 1912) and Wolcott (1898-1905) represent the earliest comprehensive works on American water mites. The papers of Marshall (1903-1946) list many species, but are not summarized. Mitchell (1954), whose check list represents the first modern attempt to examine the extent of work on North American water mites, lists 291 species which had been reported from this continent at that time. That paper is based primarily on those species in the collection of the Chicago Natural History Museum. Habeeb (1959) lists 446 species and subspecies, but in the absence of annotations some of the listings remain questionable.

A description is offered below for an unusual species of Pimplopterus recently reared from the larch twig borer, Argyresthia laricella Kft., in several localities in Eastern Canada. I am indebted to my associate Mr. C. D. F. Miller, who fist drew my attention to the species and the peculiar features of its ovipositor, and to officers at several Forest Biology laboratories in Canada, who have kindly provided an excellent series of reared specimens.

This paper includes descriptions of a new species of Iziphya Nevsky and one of Euschizaphis Hille Ris Lambers. The former genus is well represented in North America, but Euschizaphis, which is best known for its association with the Juncaginaceae, has not been previously recorded from the western hemisphere.

Iziphya punctatella, new species

Apterous Viviparous Female.–Colour when alive: Ground colour of head and body yellow with black spots around the bases of most of the setae (Fig. 4). Antennae dark except for the basal half of segment III which is yellow; apex of rostrum dark; legs black except apical two-thirds of tibiae which are colourless. Colour when macerated: Essentially as when alive, but yellow areas colourless or nearly so.

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.

During studies of the locomotory behaviour of blowfly adults, one of us G.W.G.) developed a simple tilting-type actograph wherein an electrical circuit was opened or closed each time a fly moved from one end of a small cage to the other. Circuits from six such cages were connected to solenoid-activated pens on an event recorder so that movements in each case were recorded as crosslines on the respective pen records. At peak activity, an individual fly may activate a pen up to 4,800 times during a 24-hour period. With six flies active at the same time, abstraction of a day's chart was a formidable and time consuming task. In analysing the data, activity counts over consecutive half-hour periods proved adequate, and some method was sought whereby half-hour activity records could be obtained. Six electrically operated counters were arranged so that they were activated by the closing of contacts attached to their corresponding pens. Thus, each time an actograph circuit was closed, a pen was activated producing a crossline on the chart, and a count of fly activity was registered by a corresponding counter. To simplify the situation further, some method of automatically photographing the counter dials at half-hour intervals was required. The photographic apparatus subsequently developed proved to be simple, inexpensive, and reliable. Because it is adaptable for use in many situations requiring photographic records at pre-set intervals, details of its construction arc reported herein.

The genus Roederioides was erected by Coquillett in 1901 for the single species juncta Coquillett, described from Saranac Inn, New York. The species has since been recorded only from Mt. Washington, New Hampshire. A second species has been described from the Madeiras by Frey. This paper describes five new species from North America and presents a revised description of the genus.

The type of the genus, juncta, was collected in association with black flies, and recent collections have been made from black fly swarms. It is possible that juncta, and possibly other species of the genus, are predators of black flies, both as adults and as larvae.

The apple aphid, Aphis pomi DeG., has long been a problem in British Columbia orchards (13), but has become particularly serious in the last few years (14, 15). Infestations are common on both bearing and young trees. Aphids occur especially at the terminal parts of new growth, suckers and sprouts. They reproduce extremely rapidly and large numbers cause curling and deformatinn of leaves. Further, this distortion of the leaves then protects the aphid colonies from spray application to some extent, and in clumps of such leaves, unharmed survivors are often found after the most thorough spraying. However, even where efficient spray application has been made before the leaf-curling stage has been reached, reinfestation and recolonization, presumably from outside sources, is a common occurrence. A search for “persistent” aphicides, that would at the same time give control of other common orchard pests such as codling moth, has been in progress at this laboratory for some years and in particular, Diazinon (15), Trithion (14), and Sevin (6) have been studied.

Neodiprion sawflies are economic pests in pine plantations in eastern and southern United States and eastern Canada. While not a serious problem in California at the present time, they will probably become so with the advent of more intensive forest management.

Little is known of the species present in California. The only specific study was that concerned with the Neodiprion abietis complex on white fir in 1952 (Struble, 1957). Miscellaneous data are available from the survey records of the Pacific Southwest Forest and Range Experiment Station, Berkeley.

The two new genera and species described in this paper can be distinguished from other rose-infesting aphids in North America by means of the key given below. Specimens of Macrosiphum nigromaculosum Macdougall were not available for examination and this species has been worked into the key on the basis of descriptions by Macdougall (1926) and Palmer (1952).

Under certain environmental conditions the resistance of wheats to the wheat stem sawfly, Cephus cinctus Nort., may be reduced or even lost. In addition, these varieties are not suitable for all of the region where the sawfly is a problem. To assist in the improvement of the presently resistant wheats, studies were begun in 1953 to determine the nature of the resistance to the sawfly. The present paper deals with the effects of various spring wheats and of different parts of the stems of these wheats on the hatching of the egg of the sawfly and presents evidence for hypotheses on the cause of these effects. Although several authors have reported on resistance to the sawfly (Ainslie, 1920; Criddle, 1915, 1922; Farstad, 1940; Farstad and Platt, 1946; Kemp, 1934; Platt et al., 1948; Roemhild, 1954; Roberts, 1954), none has dealt with the effects of the host on the egg alone.

Names have been requested for the following Ichneumonidae for use in publications on the parasites of a lepidopterous twig borer (Argyresthia lariccella Kft.) on tamarack (Larix laricina DuRoi).

Phaeogenes laricellae, new species

This species is closely related to P. epinotiae Cush. but may be distinguished by the very elongated and flattened thorax (of normal build in epinotiae), the smooth and shining clypeus (mostly coriaceous in epinotiae), and the small sub-apical ridge on the female hind coxa (hind coxa unarmed in female epinotiae).

Cocoons of winter moth, Operophtera brumata (L.), reared from larvae collected in Europe, were imported to obtain insect parasites for release in Canada. Normally the sequence of handling the host cocoons consisted of: summer storage (July to October); autumn storage (October to December) during which host emergence occurred; winter storage (January to May); and, finally, a period of incubation (May to June) to obtain in time for release against the larval stage of the host.