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.

Lately there has been a concerted effort to elucidate the structure and function of the stylet bundle of suctorial insects. Aphids have received special attention because of their importance as vectors of plant viruses. Several workers have described their observations of stylets penetrating translucent tissues or membranes; for example, Bradley (1952), Mittler (1954), and van Hoof (1958).

The movements most easily seen are rapid alternate oscillations at the stylet tips and a back and forth swinging of the entire stylet bundle as it enters a cell or other liquid medium.

Little is known about the acarofauna associated with wood-boring beetles in Canada, including long-horned beetles (Coleoptera: Cerambycidae). Herein, we assessed the prevalence, abundance, diversity, phenology, and attachment location of mesostigmatic mites (Acari: Mesostigmata) associated with Monochamus scutellatus (Say), and tested whether the abundance and prevalence of mites differed between male and female beetles. A total of 176 beetles were collected in two sites in eastern Ontario in 2008 and 2009 using Lindgren funnel traps baited with α-pinene and ethanol lures, and 71% of hosts had mesostigmatic mites. A total of 2486 mites were collected, representing eight species, four genera, and three families (Digamasellidae, Trematuridae, and Melicharidae). Average prevalence was variable across mite species, and the number of mites per infested beetle also varied across species. Many of the mite species collected in this study have been reported from other cerambycid species, as well as from other wood-boring beetles, such as bark beetles. There was no significant sex bias in the abundance or prevalence of mites between male and female M. scutellatus, which suggests that there is no selective advantage for mites to disperse on females. This study represents the first quantitative investigation of the mites associated with M. scutellatus in Canada.

Interest in the growth of insect head capsules was aroused by the observation of Dyar (2) that for a number of lepidopterous larvae the ratio of the width of the larval head capsule in a given instar to that in the following instar tends to be constant throughout development, This observation, generally known as “Dyar's Law” or “Dyar's Rule”, has proven valid for many lepidopterous larvae, for whch it was proposed. Many attempts have been made to apply Dyar's Rule to insects of other orders. Various authors, notably Miles (6) and Taylor (71, have considered the application of Dyar's Rule to sawfly larvae, and although they report some inconsistencies, they conclude that the rule is useful if its application is restricted to checking upon the number of feeding instars. The head capsules of non-feeding prcpupal sawfly larvae are generally of the same size as those of the last feeding instar, so that this stage is not expected to satisfy Dyar's Rule.

During a study on the life history and ecology of the woolly pine needle aphid, Schizolachnus pini-radiatae (Davidson), in a seven-year-old pine stand in Kirkwood township, Ontario, during the summer of 1960 (Grobler, 1962), a number of dead aphids were found the first week in September. These aphids, mummified in appearance, were shown to be infected by the fungus Empusa (= Entomophthora) aphidis Hoffman.

The majority of caddisflies selected for discussion in this paper are from Mexico. The Mexican Trichopterous fauna should contain a large number of genera and species, however, relatively few have been recorded, or described from that country. The phylogeny of many nearctic species will be better understood when our knowledge of the Mexican fauna is more complete. With this as the objective, most of the new species selected for description herein will further elucidate our knowledge of the Trichoptera.

One new species of Wormaldia, four new Polycentropus, two new Limnephilus and two new Oecetis have been selected for description. The unknown female of Limnephilus discolor is described. Types are in the senior author's collection unless otherwise indicated.

A comparison of the effects of infestation by known numbers of pea aphids, Acyrthosiphon pisum (Harris), on six field pea cultivars was made in field cage tests. The largest population of aphids developed on the cultivar Trapper and the smallest on the cultivar Century, with differences in aphid numbers between these cultivars significant for mature plants. Infested plants of Trapper had a significantly lower number of pods per plant, and infested plants of all cultivars had decreased seed weights, both per metre row and of 250 seeds, when compared with control plants. In all cultivars except Trapper, the most severely affected yield component was weight of 250 seeds.

During 1965–66, studies of a large population of Hylastes nigrinus (Mannerheim), breeding in roots and stumps of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, killed by Dendroctonus pseudotsugae Hopkins in 1964, were conducted on Marys Peak in western Oregon, near the city of Corvallis.

The emergence and flight of H. nigrinus were at their maximum in late April and early May. Emergence was strongly influenced by temperature and seldom occurred at temperatures below 61° and above 75°F. Flight behavior was strongly affected by light intensity, peaking at intensities between 300 and 1200 ft-c during the late afternoon or early evening. Maturation feeding was found to take place on small roots of dead, old Douglas-fir and on roots of young Douglas-fir weakened after replanting. Egg-galleries, normally running parallel with the grain of the wood, were initiated in June and eggs were kid from the end of that month. Five larval instars were found. Adult beetles as well as full-grown larvae overwintered in the galleries. The majority of the population completed development in 1 year.

The larval population of H. nigrinus was heavily decimated during the fall of 1965 by larvae of the dipteron fly, Medetera vidua Wheeler (Doliohopodidae). Emergence data are presented for scolytid, curculionid, cerambycid, and buprestid species competing with H. nigrinus in stumps or roots.

Field populations of the European red mite, Panonychus ulmi (Koch), in Nova Scotia were separated into eggs, larvae, protonymphs, deutonymphs, and adults and the length of time each stage was present for each generation was determined in 1967 and 1968. The duration of each generation was similar in both years, although the diapause eggs hatched later in 1967 than in the succeeding year. Detailed information on the seasonal history is necessary in assessing red mite mortality and in timing of chemical controls of this pest.

The chorionic architecture, including the general and fine structure, of the eggshell of the microtype egg of the tachinid Euexorista futilis (Osten Sacken) is described. It is about 220 μm long, flattened dorso-ventrally, and has distinct dorsal and ventral chorions, each of which is differently structured. The surface features of the microtype eggs of an additional 20 tachinid species are described, and the usefulness of these features in taxonomic decisions is discussed. Three new combinations are used: Allophorocera arator (Aldrich), Cyzenis browni (Curran), and Eufrontina mitis (Curran).

Efficient methods are described for mass rearing, picking and spreading in the field millions of aphids. The originality of the method lies in the use of a powder that prevents aphids from sticking to the equipment or to each other, and makes them a flowable substance that can be spread with a special apparatus.

The stout, red-and-black adults of the milkweed beetle are common during June and July on the leaves and flowers of Asclepias spp. over most of the range of these plants. It has long been known that the larvae inhabit the soil, feeding on the roots of the host. Craighead (1923) found larval galleries extending from root to root in the soil, and upwrards to immediately below the soil surface, where pupation occurs. My own observations corrolborate Craighead's; larvae were found in the soil feeding on the outside of the milkweed roots. Thus the larvae are free-living, terricolous insects, much like white grubs.

At the time of my retirement on December 31, 1950, a number of notes on synonymy and generic transfers had accumulated. Many of these are thought worthy of publication and this paper is made up of a number of them. Those included notes which deal with Nearctic forms will clarify the treatment of certlin genera and species in the catalog of North American Hymenoptera, now in process of publication by the U.S. Department of Agiculture, the Chalcidoidea section of which catalog has assembled and edited by O. Peck of the Canadian Department of Agriculture but which is based in great part upon the classification and arrangement of the collection in the United States National Museum. The catalog will probably appear in print before this paper does. Several notes dealing with forms not known to occur in the Nearctic region, hence not appearing in the catalog, are also included.

Apple maggot eggs, Rhagoletis pomonella (Walsh), hatched equally well in apples on the tree and in picked fruit. Many larvae completed development in all different maturities of picked fruit and development and survival were similar in different cultivars. In contrast, larval mortality was high in apples remaining on the tree, particularly in fruit infested in late June and July. More larvae survived in the unpicked fruit of the earlier ripening, softer cultivars, Wealthy and McIntosh, than in the later ripening Rhode Island Greening and Rome apples.

Pheromone traps were more efficient than blacklight traps for detecting and monitoring adult populations of fall armyworm, Spodoptera frugiperda (J.E. Smith), in southwestern Ontario. Several dispenser–chemical combinations were strongly attractive but best results were obtained with sticky traps baited with rubber septa impregnated with combinations of (Z)-9-dodecenyl acetate and (Z)-9-tetradecenyl acetate.

Since the earliest days of this century the interactions of parasitic Hymenoptera that attack the same host species have been reported from time to time in connection with studies on the natural enemy fauna of pest insects. These studies indicate that the synchronous attack by two or more parasitic species on an individual of a host population, multiple parasitism, is of little, if any, importance in the economy of that population, whereas the attack by two or more parasitic species on a sequence of a host’s developmental stages and instars, sequential parasitism, may be highly important, especially from the standpoint of host regulation. Since the host-regulating capacity of a parasite species may vary both seasonally and geographically, sequential parasitism is highly conducive to continuity in the conservation of the host’s food supply, the practical measure of regulative parasitism. The cooperative as well as the competitive aspects of sequential parasitism are discussed. The parasite fauna of the black scale, Saissetia oleae (Bernard), is used to exemplify these aspects of parasitism.

Crude tall oil and two of its derivatives were assessed for antifeedant and growth inhibitory effects, via incorporation into an artificial diet, in the variegated cutworm (Peridroma saucia Hübner). The substances tested are both toxic to neonate P. saucia and inhibitory to larval growth. The dietary LC50 (lethal concentration for 50% mortality) values are 4.3, 4.7, and 5.3% fresh weight for depitched tall oil (DTO), crude tall oil (CTO), and tall oil pitch (TOP), respectively. These materials significantly reduced growth, feeding, and dietary utilization by first-, second-, third-, and fourth-instar larvae in chronic larval growth bioassays, choice and no-choice feeding tests, and nutritional experiments. The EC50s (effective concentration to inhibit growth by 50% relative to controls) of DTO, CTO, and TOP were 1.4, 2.0, and ≥2.4%, respectively, when first-instar larvae fed on treated diets for 10 days. DTO significantly reduced both growth and consumption rates with corresponding reduction in the efficiency of conversion of food (i.e. nutritional efficiency), suggesting that both antifeedant and toxic effects are involved in larval growth inhibition. DTO and CTO are consistently more biologically active than TOP. Our results suggest that an environmentally sound, low cost natural pest control agent may be developed based on tall oil.

A display that exemplifies relationships between mites and insects is especially appropriate for an exhibit of acarology at the Centennial of Entomology in Canada. Mites of some 15 genera in ten families are associated with bark beetles. Those of a species group in the genus Tarsonemoides (Acarina: Tarsonemidae) are specialized as egg parasites of Ips (Scolytidae). This exhibit is based on research by Lindquist and Bedard (1961: Canad. Ent. 93: 982-999) on species of Tarsonemoides with Ips in California and is illustrated with similar material from Toronto.

A third Neotropical species of the genus Docosia Winnertz is described from the Colombian Andes. Three males and four females of D. adusta sp. nov. from Cundinamarca, Colombia, collected at 3600m elevation were examined. Detailed illustrations of the male and female terminalia are presented and morphological differences in relation to those of other species of the genus are discussed. The relationships between Holarctic and Neotropical species within Docosia are discussed and overlap of circumantarctic, tropical, and Nearctic elements in the northern Andes is considered.