The alimentary canal of stored grain beetles is relatively simple compared to those of the higher orders of insects. But there are certain specializations from the generalized alimentary canal of the insect described by Snodgrass (1935). Striking similarities of structure have been observed in course of morphological investigation of the alimentary canals of two distantly related groups of beetles living on stored cereals. The differences between the two groups are few.

This technique was developed to discover whether a tyroglyphid mite, Tyrophagus castellanii Hirst, was feeding on moulds growing on a food medium rather than on the food medium itself. Later on the technique was also found satisfactory for obtaining, under controlled temperature and humidity conditions, individual development records for all stages of the life-cycle of the mite.

In Eastern Canada four species of aphids, Macrosiphum solanifolii (Ashm.), Myzus persicae (Sulz.), Aulacorthum solani (Kltb.), and Aphis abbreviata Patch infest potatoes. Since 1953 it has been possible to rear the four species in the greenhouse throughout the year (MacGillivray, 1955).

The life-histories of these species have been discussed by Patch (1925). The asexual phase of M. persicae has been studied by Horsfall (1924), Weed (1927), Bonnemaison (1951), and Sylvester (1954), and that of M. solanifolii by Smith (1919).

Crosby and Bishop (1925) published a comprehensive revision of the New World genus Ceraticelus, and from time to time other species have been described as they appeared. The following descriptions of two additional species were based upon specimens in the American Museum of Natural History in New York. All type material was deposited in that institution.

The house cricket, Acheta domesticus (L.) (Gryllidae, Orthoptera), is a cosmopolitan and easily available insect, and is most suitable as a test animal for physiological research, as has been pointed out by Stone (1953). However, in spite of the long familiarity of entonlologists with this insect it has received very little attention in the literature, no doubt because it has never been of economic importance in Europe or North America. Such quantitative observations on its development as do exist are rather fragmentary (Kemper, 1937; Stone, 1953; Busvine, 1955). The present article describes, in a somewhat more precise way, the rate of development of the nymph of the house cricket at various temperatures and the number and duration of the nymphal stadia, as well as a satisfactory method of rearing the insect and observations on its fecundity.

The beech leaf tier, Psilocorsis faginella (Chamb.) is common on American beech, Fagus grandifolia Ehrh., in stands of northern hardwoods throughout Nova Scotia. During the feeding stage, the insect is conspicuous because of its leaf-tying habit (Fig. 1).

The literature on P. faginella is mostly taxonomic. Forbes (1923) and Gaighead (1950) mentioned the leaf-tying habit of the larva and the colour of the ultimate instar. Chambers (1872) originally described the adult as Hagno faginella, then placed it in the genus Cryptolechia (1878). The genus was later changed to Psilocorsis (Busck, 1908). Clark (1941) described the adult in more detail and listed Psilocorsis ferruginosa (Zeller) as a synonym.

A series of rearing chambers that have given satisfactory control of temperature and humidity have been in use in the entomological laboratory at Kentville during the past three years. The unit requires very little attention except a service check of the cabinets every two or three months.

The dimensions are given in Fig. 1 except for the depth, which is 30 inches on the outside. The cabinet is constructed of 3/4-inch plywood without a supporting frame. Trays with perforated steel bottoms are arranged inside the cabinet on adjustable shelf brackets. The cabinet is provided with an upper and a lower door with removable jamb between them that may be removed when installing the trays in the cabinet. The doors are provided with a double glass window, which in turn is covered by a plywood door. A thermostat and a hygrostat are installed on the inside wall of the chamber about one foot from the bottom. The cabinet sets on a 15-inch base as shown in Fig. 1. The cabinet is painted inside with a steam-resistant paint to facilitate cleaning, and is provided with two 15-watt fluorescent lights inside at the top.

Several Canadian workers have reported various results in the control of the onion maggot, Hylemya antiqua (Meig.), with chemicals applied to the soil surface (Dustan, 1938; Matthewman et al., 1942; McLeod, 1946; Perron et al., 1953; Finlayson and Handford, 1954). In these tests, the date of the first application of insecticide coincided with early oviposition of the insect, the second and third applications following at weekly or ten-day intervals. Satisfactory control was therefore dependent to a great extent on the grower's ability to recognize the beginning of oviposition by the pest in the field. However, many growers find this recognition difficult and poor control often results from the three-application program.

That insect parasites regulate and, in the case of newly introduced species, sometimes reduce the average density of insect pests has led to an exmination of the properties of parasites in general. Consideration has been given to the manner in which parasites select hosts for oviposition and to the physiological and psychological basis of this selection. The distribution of parasite progeny among suitable hosts has been analysed in many cases, for the fewer the hostS that are superparasitized for any given number of parasite eggs laid the greater the efficiency of the parasite in reducing host density. It is obvious that before the factors of host selection and superparasitism become important in host-parasite interaction the parasite must find the host individuals. When the hosts are confined to a relatively small area the potential oviposition of the parasite, subject to discrimination among hosts and restraint in oviposition, often determines the level of parasitism. As distance between individuals of the host population becomes greater, however, it is necessary for the parasite to search the environment more extensively. Therefore, the ability of the parasite to find hosts is a factor of prime importance in determining its influence on the density of its host. The success with which a parasite discovers hosts in relation to host density is determined, of course, by several characteristics of the parasite species and by the modification of these characteristics through variations in the physical environment.

This species is closely related to Triaspis (T.) halidayi Martin, from South Dakota, and Triaspis (T.) kurtogaster Martin, from eastern North America. In all three species the abdominal carapace is relatively strongly longitudinally rugoso-punctate and apically emarginate, and the clypeus is transverse. The new species may be readily distinguished from kurtogaster by its non-reflexed margin of the clypeus and by its less strongly developed marginal lamella of the third abdominal tergite, and may be separated from halidayi by its stronger, coarser, general rugoseness and darker colour.