The setal patterns of the anterior abdominal segments of first-instar and older larvae in more than 50 genera representing the six Nearctic subfamilies of Geometridae, have been examined. The significant variations in these patterns have been summarized and a key to the subfamilies is presented. Relationships within the Geometridae are discussed.

A synopsis is given of what is known from the literature of the genus Asiphonaphis in North America. Four species have been described: pruni, anogis, utahensis and carolinensis. There is evidence that the species described as A. carolinensis is the same as A. anogis. Measurements are given of series of fundatrices, alate and viviparous females, males and oviparae of A. pruni collected in Manitoba.

Pine leaf aphid infestation produces not only a general reduction in radial growth of white pine but also a modification of the normal pattern of annual radial increment along the length of the stem. The greatest growth reduction occurs in the lower stem with proportionately less in the midcrown area and least in the top. This appears to reflect the distribution of branch mortality which is greatest in the mid- and lower crown. Several defoliators studied by other workers produce the greatest effect on radial growth and on foliage survival in the tops of the tree.

Stem elongation reduction occurs only after crown damage and aphid infestation becomes extreme. Lighter infestations are reflected, however, in reduced needle length in the year of attack followed by reduced branch elongation in the year following attack. The combination of stunted and normal needles alternating with stunted and normal branch internodes is probably a unique characteristic of pine leaf aphid damage.

Mining bees of the genus Evylaeus are remarkable in that their behaviour ranges from a strictly solitary to a complex social level. Knowledge of the many sexually dimorphic species is fragmentary, and the present paper describes one new species from northern Ontario and associates the sexes in two others. Biological notes and the illustration of male terminalia of closely related species are presented to facilitate their separation.

This exhibit represents part of the work of the Department of Zoology in the past 5 years, and others who have contributed to it are F. Matsumura, Z. H. Abedi, T. Kimura, P. G. Fast, J. G. Towgood, J. N. Telford and N. H. Khan.

The work with the mosquito Aedes aegypti has involved study of 8 susceptible strains. The mechanism of DDT-resistance has been found to be associated with its detoxication by an enzymic process of dehydrochlorination to DDE; the amount of DDE produced has been found to be directly proportional to the resistance level, both by experiments with larvae in vivo and with larval homogenates incubated with DDT and glutathione in vitro. A secondary resistance mechanism in American strains has been a very pronounced secretion and excretion of peritrophic membrane by the larvae.

Betulaphis quadrituberculata (Kalt.) is an inconspicuous leaf-feeding aphid on birches in North America and Europe, now recorded on Betula papyrifera Marsh and B. alleghaniensis Britt. in the Province of New Brunswick. Some aspects of its morphology are described in order to complement the incomplete accounts already in the literature. The viviparae are seasonally polymorphic in size and color.

In New Brunswick the aphid has an annual monoecious holocycle comprising up to 10 generations. The seasonal history and habits of the various morphs are described. The insect disperses mainly by the flight activity of the stem-mothers in spring, but in succeeding generations almost all individuals are apterous and rather sedentary in habit. Data on rate of development and fecundity are presented and briefly discussed as factors contributing to the seasonal population pattern.

A comparison of four sex determination methods shows that microscopic observation of the elytral declivity is the most accurate and rapid method for sexing large quantities of Douglas-fir beetles.

Measurements and analyses of juniper fragments on bagworm cases reveal striking regularities that suggest the behavior that may produce them. Fragments are always attached at their extreme upper ends, and the great majority are oriented with their apical ends directed downwards towards the lower end of the bag. The proportion so oriented increases towards the cop of the bag, as does the average length of the fragments. Binomial analysis reveals no evidence of contagious orientation of adjacent fragments. It is suggested that the bagworm may not deliberately “decorate” its case, but that these fragments represent the remains of foliage anchored against the bag, so that the bagworm may feed with minimal exposure from its protecting case.

Thousands of lepidopterous larvae representing a wide range of species are collected every year in Ontario by the Forest Insect Survey. Many of these require microscopic examination for identification. During a 10-year period I have only found one specimen with an extra pedal appendage.

In June 1963, a larva with an extra anal proleg on the right side was collected by H. G. McPhee near Thessalon, Ont., on the north shore of Lake Huron. The species was Epinotia solandriana Linn., a leaf roller on white birch, Betula papyrifera Marsh. A subsequent large collection from the same area contained only normal specimens.

An abbreviated method for making balsam mounts is described. It uses the known rapid-clearing properties of phenolic solutions and eliminates the necessity of dehydration in various strengths of alcohol.

A variety of wild and domestic mammals from Manitoba were examined for external parasites, and fleas were recovered from 15 species. A total of 17 species of fleas were collected, of which 10 were first records for Manitoba, one was a subspecies new to the area, and 7 were recorded from new hosts. Orchopeas leucopus and Monopsyllus wagneri were the most abundant species taken from wild animals, being found on the most abundant host, Peromyscus maniculatus. Flea populations reached a peak in late summer, and were found in greater numbers on juvenile than on older hosts, on lactating than on other adults, and on solitary than on gregarious species.

The European spruce sawfly, Diprion hercyniae (Htg.), was first discovered in Canada in 1930 and in the next few years attained outbreak proportions in spruce forests over large areas in the Gaspé Peninsula and New Brunswick. The accidental introduction of a polyhedrosis in the early 1930’s was responsible for the rapid decline of the infestation, and under the influence of both disease and introduced parasites, densities throughout the range of the sawfly have been fluctuating at very low levels for the past 20 years. Population studies have been conducted on this insect in New Brunswick since 1938 and data are now available for 50 consecutive generations over a 25-year period. Morris’ key-factor approach, using parasites, disease and weather as the key factors, has been used in the analyses of the data. Although disease obscured the effect of other control factors, during high sawfly densities, larval parasites have been largely responsible for maintaining the low densities experienced in New Brunswick for the past 20 years. A pronounced change in the relative importance of the different parasite species and in the amount of cocoon predation attributable to small mammals and wireworms has occurred during the change from high to low host densities.

Eight species of Thanatus are recognized in North America; four are holarctic in range and four nearctic. The holarctic species are T. coloradensis Keyserling, 1880, T. formicinus (Clerck 1757), T. striatus C. L. Koch, 1845, and T. vulgaris Simon, 1870 (=T. peninsulanus Banks, 1898, NEW SYNONYMY). The four nearctic species are T. altimontis Gertsch, 1933, T. arcticus Thorell, 1872, T. patriciae (Lowrie and Gertsch 1955), and T. rubicellus Mello-Leitao, 1929 (=T. rowani Gertsch, 1933, NEW SYNONYMY).

Three questions are asked in this paper.

(1) Is the numerical stability of an insect species through time a function of the number of species of food eaten by that species?

(2) Is the information content of a genus related to the stability of species in the genus?

(3) Is the information content of an insect genus related to the number of species of food eaten by the species in that genus?

Data in the Canadian Forest Insect Survey bulletins on Forest Macrolepidoptera are used to answer all three questions; data on parasitic Hymenoptera stored in museums are used to answer the third question. There is some indication that stability decreases with number of host species, and that information content of a genus is less, the less the stability of the species it contains. The evidence from both bodies of data suggests that information content of a genus is less, the greater the average number of species of food eaten by the species in the genus.

The Pyrgomorphidae represent a distinctive family of acridoid Orthoptera comprising 127 genera and over 400 species. The systematic history of the group is outlined and its name is discussed. On the basis of external morphology and phallic structures it has been found possible to divide the family into tribes. Most of these have been recognized previously, but several new ones have been erected to accommodate anomalous genera or parts of former tribes that have proved to be heterogeneous. The genera fall into no fewer than 29 tribes and 8 subtribes, which reflect the antiquity of the group; phylogenetic relationships remain rather obscure. An extensive key to the tribes and subtribes (incorporating both external and phallic characters) is given and the genera belonging to each are listed. Diagnoses of three new genera and a new subgenus are appended. Geographical distribution is discussed. The great majority of Pyrgomorphidae are found in the Old World tropics and subtropics, but some are American and a few reach temperate latitudes both north and south. A very high degree of endemism amongst genera is shown by all regions in which the group occurs, except the Palaearctic. The African and Malagasy faunas are the richest, but the group probably originated further east. Madagascar, Australia, the Papuan subregion and C. and S. America all have their own very distinctive tribes and genera. No genera are common to Old and New Worlds. The latter was probably invaded from Asia at least twice. Pyrgomorphidae appear to be comparatively recently incursive into the Palaearctic region. A new Palaearctic fossil genus is proposed.

The eggs and oviposition sites of six species of predatory mirids from Nova Scotia apple orchards are described. These species are Hyaliodes harti Knight, Atractotomus mali (Meyer), Deraeocoris fasciolus Knight, Diaphnidia pellucida Uhler, Blepharidopterus angulatus (Fall), and Pilophorus perplexus D. & S. The differences between the eggs of each species are great enough to identify them in situ.

The species of leafhopper described belongs to the obliqua group and the dorsal colour pattern consists of the usual oblique stripes of reddish pigment so typical of this group. The species most closely resembles E. aspera from which it can be distinguished by differences in the male genitalia. The preferred hosts are apparently Betula spp.

During intermolt in the fifth instar nymph the epidermal cells are compact, with many mitochondria which appear dense, lack well defined cristae, and are considered relatively inactive. The cell membranes are much folded and show plasmodesmata and microvilli at the juxtaposition of two cell membranes. The endoplasmic reticulum is well formed and well supplied with ribosomes; in the compacted cells the reticular membranes may assume bizarre shapes such as a ball of concentric rings. The nuclei are small with inconspicuous nucleoli.

During cocoon construction the predominant movement made by larvae of the three honey bee castes is a forward somersault which is made dorsal side outermost. Worker, drone, and queen larvae complete one somersault in 52, 46 or 67 (at two different times), and 32 minutes respectively with the total number of somersaults made during cocoon construction being 27-37, 40-50, and 40-80 respectively; the larvae take 37, 54, and 30 hours respectively to complete their cocoons. Weight changes of larvae before and after the cocoons are made are given.

Worker and drone larvae build completely enclosed cocoons directly on the side walls and end walls of cells, but queen larvae leave spaces between the cappings and the cocoons and do not cover the bases of their cells with cocoon material.

Cocoons consist of silk gland secretion (in thin sheets and threads), a colourless material, a light yellow material, and a more solid brown material (faeces); the last three are discharged from the larval anus. When, how, and where these various secretions and excretions are placed in the cocoon, and their probable origins, are described. Possibly some brood food is incorporated into the cocoon but skin secretions or larval blood are not.

Euxoa piniae new species is described from material collected at Johnsville, Plumas County, California and compared with E. brunneigera latebra Benjamin, its closest relative.