A new genus, Misturaphis, is described, with type-species Misturaphis shiloensis new species, from Artemisia caudata Michx. Cryptaphis bromi new species is described from Bromus inermis Leyss. Asiphonaphis anogis Hottes and Frison is declared a junior synonym of Pergandeidia corni Tissot, and P. corni is re-designated as type species of the genus Pseudasiphonaphis, with new name Pseudasiphonaphis corni (Tissot).

Field collections of late instar larvae of Choristoneura populations were obtained from a wide range of localities. These populations were found to fall into nine taxonomic entities, either species or subspecies. A tenth group is of uncertain affiliation. Five of these entities have tree species of the subfamily Abieteae as their hosts, whereas the other four (probably five) characteristically feed on species of the subfamily Pinoideae. Furthermore, each of the budworm species, or subspecies, is associated with a characteristic forest region.

This is the fourth in a series of papers leading to the development of population models for Hyphantria cunea Drury in New Brunswick and Nova Scotia. In 1961 and 1962 seasonal trends were obtained for moth eclosion, larval development, nest population, parasitism, and other factors. It is concluded that one annual census of nests from a moving vehicle can provide an effective method for comparing changes in population and natural control factors over diverse climatic areas. The timing of the census in each area is important, as well as the collection of nests for data on development, colony size, parasitism, and predation.

The seasonal trends also add support to earlier hypotheses concerning the role of weather in the population dynamics of H. cunea, and reveal the nature of an important interaction between the mortality induced by weather and that induced by the main parasite, Campoplex validus Cress.

Larvae of Hypoderma bovis (L.) and H. lineatum (De Vill.) when incubated with the substrate acetylthiocholine iodide showed the presence of cholinesterase throughout the central nervous system and sense organs, in gonads, oenocytes, Malpighian tubes, anlagen of adult structures, part of the posterior midintestine, and at the junctions of the muscles of the body wall. Incubation with the substrate 5-bromoindoxyl acetate showed all the aforementioned and in addition demonstrated the presence of aliesterase (organophosphorus-sensitive esterase) in the cell cytoplasm of all the midintestinal epithelium, the ring gland, tracheal epithelium, salivary duct epithelium, and in the perineurium of the nerve sheath. Aromesterase (organophosphorus-resistant esterase) was particularly abundant in the epithelium of the midintestine. Lipase was prominent in the lipid droplets of the fat body cells and in similar droplets in the haemocytes.

When the larvae or their tissues, prior to incubation with the substrates, were treated with any one of the three organophosphorus insecticides coumaphos (Co-Ral), trichlorfon (Neguvon, Dipterex), or Ruelene, the cholinesterase was inhibited and so was much of the aliesterase, but not the aromesterase or lipase. Fixation of the larval tissues in formalin did not result in loss of enzyme activity, but on the other hand was not necessary for good histochemical demonstration of the enzymes.

It is concluded that these insecticides by their anticholinesterase action kill the first-instar cattle grubs before the latter can migrate to the lumbar region of the bovine host.

For the first time the male of Sirex juvencus californicus (Ashmead) (= Sirex obesus Bradley, new synonymy) is described; the female is redescribed. Biological notes on this subspecies are included, together with a key to the California species of the genus.

Lyctocoris canadensis new species is described from southwestern Quebec. The other species of Lyctocoris known to occur in North America are L. campestris (Fabricius), L. doris Van Duzee, L. elongatus (Reuter), L. mexicanus Kelton, L. okanaganus Kelton & Anderson, L. rostratus Kelton & Anderson, L. stalii (Reuter), and L. tuberosus Kelton & Anderson. Species are keyed, known information on their ecology is given, and male genitalia and female abdominal segments are illustrated.

Pigmentation of heads and prothoracic shields of last-instar larvae, colour of pupae, and frequencies of haemolymph colour morphs in fresh pupae are used to support the taxonomic differentiation of the following members of the genus Choristoneura: fumiferana, biennis, orae, occidentalis, viridis, subretiniana, pinus pinus, p. maritima, and lambertiana. These characters are statistical in nature and not competent to relate a single individual unequivocally to a taxonomic group; nevertheless, a key is developed to assist identification of populations on the basis of the characters described. Interspecific relationships within the genus are considered.

The bark-beetle genus Cactopinus, containing seven species, is reviewed. Distributional data, biological notes, a discussion of each species, and a key for the separation of all species are included. New species are: C. desertus (California) and C. depressus (San Luis Potosi, Mexico). C. cactophthorus Wood and C. mexicanus Wood are placed in a new genus, Cactopinorus.

Philodromus spp., especially praelustris Keyserlmg, and sometimes Theridion murarium were the only abundant spiders in peach orchards, though small numbers of many other species were present. No satisfactory method of sampling the population density of all species was discovered. The spider population as a whole reached a minor peak in June and a much higher peak in early August. A single tree may contain more than 200 spiders. When fed only on Panonychus ulmi (Koch), young P. praelustris eventually died without moulting; young of T. murarium moulted once or twice but their development was slower than that of those in the orchards. Chironomids were the commonest prey of P. praelustris and apparently of other spiders in the orchards.

Spiders collected from peach plots with different densities of P. ulmi and Bryobia arborea Morgan and Anderson were examined for pigments of these mites by paper chromatography. Some spiders in all collections had fed on the mites, and the percentage that had done so usually varied directly with mite density in the plots. Spiders form part of the complex of minor predators that aid the major predators in regulating the density of P. ulmi at endemic levels.

The effects of sprays of DDT, azinphos-methyl, and Ryania applied to a pear orchard on population densities of insect predators of Psylla pyricola Förster were assessed. The P. pyricola in the orchard were naturally tolerant to DDT and Ryania and highly resistant to azinphos-methyl. DDT eliminated or severely reduced numbers of Deraeocoris brevis piceatus Knight, D. fasciolus Knight, Diaphnocoris provancheri (Burque), and Campylomma verbasci (Meyer). Chrysopa carnea Stephens and C. oculata Say were moderately reduced. Anthocoris antevolens (White) and A. melanocerus Reuter were highly tolerant to DDT. Azinphos-methyl severely reduced numbers of A. antevolens, A. melanocerus, C. verbasci, and D. provancheri. C. carnea and C. oculata were moderately reduced. D. brevis piceatus and D. fasciolus were tolerant to azinphos-methyl. Ryania severely reduced numbers of A. antevolens, A. melanocerus, and C. verbasci; moderately reduced D. provancheri; and did not affect D. brevis piceatus, D. fasciolus, C. carnea, or C. oculata.

In the DDT-treated plots the relative densities of Anthocoris spp. approximately doubled compared with the untreated plots. This was probably due to removal of competition for food by other predator species. Large increases ill the relative densities of Deraeocoris spp. were also observed in the Ryania treatments, probably for similar reasons. Significant increases in the P. pyricola populations in response to removal of predation pressure by the insecticide treatments occurred in the DDT and azinphos-methyl plots bur not in the Ryania plots.

Populations of the mayfly Heptagenia hebe McDunnough in areas of New Brunswick air-sprayed with DDT for budworm control for eight successive years, when tested as nymphs taken from the streams, showed LC50 levels 3 times as high as those in untreated areas. Populations surviving an airspray in 1965 proved to be 12 to 40 times as DDT-resistant as the normal. Pre-spray populations of Stenonema fuscum (Clemens) showed a 5-fold resistance, and post-spray populations of Stenonema interpunctatum (Say) showed a 10-fold DDT resistance when those from treated areas were compared with those from untreated. The DDT-resistant nymphs of H. hebe detoxified DDT to DDE 15 times faster than the normal nymphs; DDE was also the metabolite in S. interpunctatum. In both these species the DDT-resistant nymphs absorbed roughly twice as much DDT as the normal.

The effect of temperatures on the development of a virus disease of Neodiprion swainei Midd. was studied at constant temperatures of 30° and 12 °C., and under fluctuating temperatures (15°–20 °C.) in the laboratory and outdoors. Viral concentrations of 30 × 106 polyhedra per ml. and 1 × 106 polyhedra per ml. were used. Only the higher concentration of virus was effective at 30 °C. At 12 °C. the incubation period of the disease was prolonged and mortality caused by the virus was considerably reduced for both viral concentrations. Mortality due to the virus was similar at both viral concentrations for the fluctuating temperatures which were within the optimum temperature range for larval development.

The genera Leptohyphes Eaton and Tricorythodes Ulmer are confined to the New World, and the Nearctic limits of Leptohyphes has been extended from Texas to Maryland and Utah. Useful nymphal characters are presented for both genera, and descriptions and figures are included for 22 new species of Leptohyphes Eaton, and 7 new species of Tricorythodes Ulmer.

The sawfly Diprion hercyniae (Htg.) prefers the old to the new growth of its preferred food plant, Picea glauca (Moench) Voss. The similarity between the responses by the sawfly and those by one of its parasites, the tachinid Drino bohemica Mesn., and the significance of this similarity are discussed.

The morphology of haemocytes of Blaberus giganteus (L.) was studied in vivo in adult insects, and in stained films of blood from all stages. The study included the measurement of cells and the application of several histochemical tests. It was concluded that four categories of haemocytes exist, prohaemocytes, plasmatocytes, granular haemocytes, and spherule cells, and that the last two categories are closely related, both having the capacity to concentrate neutral mucopolysaccharides in their cytoplasm. Criteria for separating the categories are given.

In New Brunswick at least nine species of Erythroneura leafhoppers feed and oviposit on birch trees. The appearance and ecological requirements of two species in the subgenus Eratoneura are described.

After feeding, gypsy moth larvae construct a silk mat (resting mat) on which they remain. Prior to molting, this mat is reinforced, or a new, dense mat is constructed (molting mat). Late in the last larval instar, a sparse cocoon is constructed. When larvae are starved, a shift in behavior is noted, with increased locomotion, irritability, and the trailing of a strand of silk as larvae wander. First-instar larvae, quiescent and anchored on resting mats, are not readily induced to spin down on silk threads; hence are not readily dispersed by wind. Hungry first-instar larvae, more apt to be spinning down, are presumed to be more readily dispersed by wind. Larvae which undergo an additional instar have a longer prefeeding phase and might be more readily dispersed than "normal' larvae. The effects of hunger may also cause the shift in diel periodicity of mid- and late-instar larvae, resulting in some dispersal of these larvae away from areas where food will be depleted.

The Nearctic species of Diadegma that have the abdomen compressed and the propodeum produced beyond the base of the hind coxa are treated as a complex composed of three species groups. A key to groups and species is provided. Two previously described species, D. stenosomus (Vier.) and D. aestivalis (Vier.), and ten new species are described and discussed from the standpoint of their taxonomy, distribution, and host relationships.

Like all other Tryphoninae, the European species of Exenterus have eggs that are attached to the host by a stalk inserted into the host integument. Their eggs present an interesting series of evolutionary steps from the typical tryphonine condition in which the egg has a small single stalk with a knob-like anchor to an extremely specialized condition in which the stalk is doubled and its two parts migrate to opposite ends of the egg; the anchoring part of the stalk is concurrently enlarged until it half encloses the egg and functions as an extremely efficient organ of attachment to the host cuticle. In dry periods the simple type of stalk becomes brittle and easily broken, resulting in the death of the parasite. The specialized eggs with protected stalks are not subject to such hazards; thus species with specialized eggs can succeed in drier climates and can better survive droughty seasons. Correlated with these specializations is an increase in range of species, and greater abundance of individuals. The success of the European species introduced into North America for biological control has been roughly proportional to the amount of specialization in the egg structure. Little is known of the life histories of the American species of Exenterus but the few facts available do not appear to contradict the type of correlation exhibited by the European species.

The composition and variation of hemolymph amino acids in larvae of nine species of the genus Neodiprion were studied. The amino acid pattern was the same in all samples analyzed. Quantitative differences were as great within as between species; hence, hemolymph amino acid data does not appear to be of taxonomic usefulness for this genus.