Physical activity in Blaberus giganteus (L.) loosely follows a recurrent temporal pattern corresponding to the light–dark cycle. Differential haemocyte counts were made from serial blood samples taken before and after dark from individual adults in a brief attempt to determine whether the haemocyte population changed regularly also with this cycle. In 4 of the 16 individuals tested there was a substantial increase in the relative number of spherule cells and a somewhat proportional decrease in granular haemocytes after dark. In this species, these two haemocyte categories differ mainly in the size and composition of their cytoplasmic inclusions. The proportional change in their numbers is therefore considered to be the result of chemistry rather than a shift in populations of entirely separate kinds of cells. Retention of the two categories may be useful for indicating physiological changes in the blood. It seems possible that the cyclic change in numbers indicated here for these categories is more usual than shown, but is not revealed by the method employed. It seems sufficiently large however to warrant consideration in the design and interpretation of experiments relating to haemocyte populations.

During June and July of 1926 while doing marine investigation at Tofino, Clayoquot Sound, on the west coast of Vancouver Island, I had the opportunity of examining certain birds for external parasites. The results from some hosts were so far removed from the normal Mallophagan population of most birds that it seemed worth while recording them at the time.

Cyzenis albicans (Fall.) has been introduced into Nova Scotia as a control measure against the winter moth, Operophtera brumata (L.). The parasite attacks the late larval stages of the winter moth, pupates within the host in the ground, and emerges in the spring. The first liberations were made at Oak Hill near Bridgewater and the dates of releases as well as the numbers released were reported by Graham (1958) as follows: 1954, 31; 1955, 1008; 1956, 1005; 1957, 250. Graham made recoveries of C. albicans from rearings of larvae collected at Oak Hill in 1956 and 1957 and found that parasitism was less than two per cent both years. While liberations have been made at other locations in the Province since 1957, no further releases have been made at or near Oak Hill.

Among the 20 geometrid species recovered from annual surveys in coniferous forests in the Swiss Alps, three species, Epirrita autumnata (Borkhausen), Agriopis aurantiaria Hübner, and Poecilopsis isabellae Harrison, were identified as sources for parasitoids that might be suitable as candidates for introduction to Newfoundland to control the eastern hemlock looper, Lambdina fiscellaria fiscellaria (Guenée). Four univoltine Hymenoptera were identified as candidates: Dusona contumax (Forster) (Ichneumonidae) from A. aurantiaria, Dusona sp. from P. isabellae, Aleiodes cf. gastritor (Thunberg) (Braconidae) from E. autumnata, and Aleiodes. sp. from P. isabellae. The candidate parasitoids were confined with their native hosts in the laboratory and observations made to gather basic biological information and define protocols for screening.

Small numbers of these parasitoids were shipped to Newfoundland and screened in the laboratory against hemlock looper larvae. Although attacks by D. contumax, Dusona sp., and A. cf. gastritor were observed, parasitoid development did not occur. All parasitoid eggs recovered from the hemlock looper larvae attacked were encapsulated. Dusona contumax, Dusona sp. from P. isabellae, A. cf. gastritor, and Aleoides sp. from P. isabellae are not recommended for introduction against the eastern hemlock looper.

Adult flies of the apple maggot, Rhagoletis pomonella (Walsh), were monitored for 6 years at Guelph, Ontario using aerial and ground-emergence traps. Two degree-day (°D) models to predict adult emergence were tested. Fifty percent of the adults were captured in an average of 809 ± 50 (SD) °D8.7 and first capture was at 638 ± 60°D6.4. Degree-day models which have been proposed previously and those developed in this study were only slightly more accurate than average calendar date for predicting adult emergence. Differences in °D requirements for emergence in each year were correlated with the length of cold period and the correlation suggested that the length of cold period preceding morphogenesis affects either the number of °D required to complete postdiapause development or the threshold temperature for development.

Juvenile hormone analogues (JHA) were fed in an artificial diet to laboratory reared Porthelria dispar (L.) larvae. The analogues used were: I: Stauffer R-20458; 1-(4′-ethylphenoxy)-6,7-epoxy-3,7-dimethyl octene. II: Altozar®. III: Hoffmann-La Roche Ro 8-5497; 10,11-epoxy-3,7,11-trimethyl-1-(2-propynyloxy)-2,6-tridecadiene. For JHA I and II mortality occurred primarily during the larval and pupal stages with overall EC50 values from 0.19 to 0.43 p.p.m. in the diet. JHA III was not toxic. The log-probit dose–mortality curves showed low slopes. Morphologic aberrations in treated larvae and pupae were observed.

As part of a comprehensive investigation on insects affecting the low-bush blueberry in New Brunswick, a study has been made since 1950 of the saw-flies present in blueberry fields in Charlotte County. Of the 19 species collected by sweeping, onIv three Neopareophora litura (Klug), Pristiphora idiota (Nort.), and Pristiphora sp., feed on blueberry; the remainder feed on other plants growing in or near the blueberry fields. Blueberry sawflies are common in New Brunswick but do not cause any serious injury. However, in Maine, Phipps (1930, pp. 107-232) reported complete defoliation of 50 acres of blueberries by sawfly larvae.

One-day-old P1 males of the almond moth, Ephestia cautella (Walker), were irradiated with 5, 10, 15, or 2 krad of gamma radiation and paired with untreated virgin females. Progeny were collected through three generations, and lines were established in theF1and F2 with all possible degrees of inbreeding and outbreeding. Radiation effects were assayed by determining mating success, sterility of pairs, average number of progeny/fertile pair, and sex ratio for pairs with males (U♂ × F1♀ U♂ × F2 ♀), females, or both sexes (F1♂ × F1♀, F2 ♂ × F2 ♀) from each dose. Results showed the greater the initial dose, the greater the reduction in the number of progeny and the greater the male to female ratio. Radiation effects on both F1 males and F1 females were greater than effects on the P1 males, though effects on F1 males were greater than effects on F1 females. Except for extinct lines, partial recovery occurred in the F2 generation though recovery was much greater in F2 females than in F2 males. In each generation males were more affected than females from the same breeding line when they were outcrossed with untreated moths. The greater the degree of inbreeding in irradiated lines, the greater the effect on both males and females. Although a high degree of population reduction occurred only in the F1 generation at a dose of 15 and 20 krad, population models showed inbreeding at the lower doses caused sufficient depression to greatly reduce abundance of a natural population for several generations after a single inundative release of substerilized males.

The following notes are based on material in the Canadian National Collection at Ottawa. A large proportion of the reared material was obtained by Dr. J. McDunnough at Bobcaygeon, Ont. in the course of his studies on the Lepidoptera of that region. His rearings of several species of Haploptilia yielded a number of parasites the habits of which have heretofore been little known in Canada. Other material mentioned below was reared by the writer and by various economic officers of the Entomological Branch staff. The determinations of the lepidopterous hosts of the Bobcaygeon material are by Dr. McDunnough.

Overwintering pear psylla, Cacopsylla pyricola (Foerster), were misted with water or with one of several dilute solutions of water and surfactant, and then exposed to a range of subzero temperatures for 24 h. Misted psylla had significantly greater mortality than unmisted controls. Increases in mortality occurred at temperatures as warm as −6°C, a temperature well within the range of conditions in the field. At extreme low temperatures (−18°C) there was virtually no mortality in the unmisted controls, whereas mortality approached or reached 100% in several of the misted groups. Temperatures necessary to kill 50% of insects estimated for topically treated psylla ranged between −2.6 and −12.7°C for surfactant-treated insects, and below −18°C for water-treated or control insects. The possibility of using surfactants and water for control of overwintering pear psylla is discussed.

Feeding studies showed that survival to adult and adult body weight were much reduced when colonies of the migratory grasshopper, Melanoplus sanguinipes (Fabricius), were reared on a diet of fresh lettuce alone. This was largely due to the high moisture content of the fresh lettuce. Dried-lettuce meal, bran, or alfalfa meal as supplements to increase the intake of solids improved survival and body weight very markedly.

Horse flies and deer flies were collected throughout the spring and summer of 1955 by the author and others in the vicinity of the Wildlife Research Station, Algonquin Park, Ontario. These collections include 2,712 females of 15 Chrysops species, three males and 278 females of 13 Tabanus species and one female of Stonemyia tranquilla (O. S.). However, tabanids collected in other years from the Park have been studied as well. In 1955 T . trepidus McD. (35%) and T. epistates O. S. (15%) together accounted for half the Tabanus species collected, and C. vittata Wied. (23%), C. montana O. S. (16%) and C. wiedemanni Kröber (15%) for more than half the species of Chrysops (Table 11).

Two general models are presented to describe the relations between the average number of insects bisected by sampling unit boundaries, the per cent edge-effect bias of mean-brood-density estimates, the shape and size of the average individual, and the shape and size of the sampling unit. The two general models, when expanded specifically for sampling late-stage mountain pine beetle broods, gave excellent fit to experimental data. The expanded equations are approximations since individual insects were considered as being rectangular in shape and the angles of the long axes of their orientation relative to the sampling unit boundary were considered to have a uniform frequency distribution. Edge-effect bias was a function of the size and shape of the organism and those of the sampling unit. Edge-effect bias resulting from faulty sampling-unit-area delineation is also considered, and suggestions are made for its reduction in sample surveys of sub-cortical insects.

Apart froni the small size of the insects the main obstacle in determining material in this genus has been the difficulty in identifying the species described by older authors. For some time been have been amassing material in the group and I believe that, with more or less topotypical specimens of every described species before me, I have tied down these names with a reasonable amount of surety.

In southwestern Ontario the European corn borer, Ostrinia nubilalis (Hbn.), produces two flights annually. The first flight, beginning in June, consists of moths from larvae that have overwintered. The midsummer, or second, flight begins late in July or early in August, and its moths are the progeny of the first flight. Until about 20 years ago the borer produced only one annual flight and was thought to be univoltine. The change in the seasonal history of the borer in Ontario was described by Wressell (1953) and Miller (1956). The literature describing similar changes in parts of the United States has been reviewed by Lees (1955) and Everett et al. (1958). Wressell (1953) summarized light trap collection data of moth flights in the Chatham, Ontario, area for the years 1932 to 1951. The summary includes the percentage of the moths that were from the midsummer flight, and it is evident that the size of this flight varies greatly from year to year. Aside from its intrinsic interest, it would be of some economic value to know what governs the size of the midsummer flight. This is a report of studies undertaken to examine the case, and to relate the findings to the larger problem of why the borer now produces a second flight where formerly it produced only one.

In pheromone-based surveys for detecting multiple species of exotic lymantriine moths (Lepidoptera: Noctuidae: Lymantriinae), spacing between traps baited with species-specific pheromone lures must be sufficient to prevent antagonistic effects of heterospecific pheromone on lure attractiveness. Conducting field experiments with the Japanese gypsy moth, Lymantria dispar japonica Motschulsky, in northern Honshu, Japan, we first determined which congeneric pheromone components have strong antagonistic effects on attraction of male moths to the conspecific pheromone (7R,8S)-cis-7,8-epoxy-2-methyloctadecane ((+)-disparlure). Since the most antagonistic compounds were pheromone/volatile components from the sympatric nun moth, L. monacha (L.), we then conducted experiments with paired traps baited with either a L. dispar (L.) pheromone lure ((+)-disparlure (50 µg)) or L. monacha pheromone lure (a mixture of (7R,8S)-cis-7,8-epoxyoctadecane ((+)-monachalure (50 µg)), (7Z)-2-methyloctadecene (5 µg), and (+)-disparlure (50 µg)). As spacing between paired traps increased (0, 0.5, 2, 7.5, 15, or 30 m), the antagonistic effect of the L. monacha lure on the attractiveness of the L. dispar lure decreased and finally disappeared. For pheromone-based detection surveys of multiple species of exotic lymantriine moths in North America to be effective, trap spacing of 15 m is recommended.

Fungi and bacteria each play a role in the natural control of many sawflies, including P. erichsonii. Parasitic fungi, for example, have been isolated from species in the following genera: Anoplonyx, Arge, Monoctenus, Neodiprion, Trichiosoma, Hemichroa, Pikonema, and Pristiphora. The isolates include species from Cephalosporium, Sorosporella, Isaria, Beauveria, Spicaria, Hirsutella, and Empusa (MacLeod, unpub.). The last five fungus genera have been isolated from larch sawfly collections made in various parts of Canada and the United States.

The family Thripidæ, though possessing many characters of peculiar interest, and being of no little importance economically, has received but very little attention from American Entomologists, either systematic or economic. With the exception of a few notes upon their habits, and descriptions of some four or five species by Dr. Fitch, and also a few notes by Mr. Walsh and Prof. Riley, concerning their food habits, scarcely anything has been written of our native species.

Without going into a discussion of the classification of the group, or the peculiar characters which seem to ally it to different orders, it will be sufficient here to state that the wings are entirely membranous and folded flat upon the back, which, with the general conformation of the body, would seem to place it with the Homopterous division of the Hemiptera. The mouth parts, however, are free, composed of both mandibles and maxillæ, and the maxillæ and labium are palpigerous—characters very diverse from those of the group just mentioned.