The types of the species of North American Scolytidae (Coleoptera) described by J. M. Swaine are catalogued. Holotypes of 62 species are listed and 48 lectotypes are selected. All types, with a few noted exceptions, are in the Canadian National Collection, Ottawa.

Choristoneura fumiferana (Clemens) and C. pinus pinus Freeman are redescribed, and the following five forms are described as new: C. biennis, British Columbia; C. occidentalis, Washington; C. orae, British Columbia; C. viridis, California, Oregon; C. pinus maritima, Pennsylvania, Massachusetts, New Jersey, Kentucky.

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.

Parasites of Acrobasis spp. found in the Ottawa, Ont., area are separated by using characters of the parasite remains left in the host cases from which the parasites emerged. Characteristics of the cephalic structures, spiracles and skins of final-instar larvae of 28 species of parasites are described and illustrated in this paper; one species was described and illustrated in an earlier paper (Finlayson 1962); and one species is described from the literature. A record of all known species of Acrobasis parasitized by the species treated in this paper is tabulated.

A revised classification of the subfamily Pimplinae (Hymenoptera: Ichneumonidae) based on characteristics of final-instar larvae is suggested and discussed. On a basis of larval characters the subfamily falls into two tribes: the Pimplini; and the Ephialtini, which consists of the subtribes Ephialtina, Polysphinctina, Poemeniina, Rhyssina and Theroniina.

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Laboratory and field experiments were designed to determine the effect of insect predators on the immature broods of Dendroctonus brevicomis LeConte. The results indicate that predation is dependent on the predator density and the time predator and prey are exposed together. Prey density was generally very high and had little effect on the rate of predation. The corroboration of laboratory and field experiments give confidence to the conclusion that the constant predation rate (0.261 prey per predator per day) can be used to estimate western pine beetle mortality from predation, provided temperatures remain within the 60° to 70°F range.

Laboratory experiments were conducted to determine the effects of bark moisture content on the survival and development of Polygraphus rufipennis (Kirby). Adults and immature stages were reared in white spruce bark of five different moisture contents for 20, 40, and 60 days. Adult activity and brood success were related to the moisture content of the bark with the adverse effects of the drier bark becoming more pronounced with time. After 40 days factors associated with high bark moisture levels, such as fungus and rate of decomposition, may have been responsible for a decrease in survival and rate of development in the moister bark.

Fifth-instar larvae of the larch sawfly, Pristiphora erichsonii (Hartig), of different weights, were deprived of food and placed in containers with moist moss. A low percentage of the early fifth-instar larvae were able to spin cocoons, but the percentage rapidly increased to a plateau as the larval weight increased. All but the heaviest larvae suffered appreciable mortality before first-year adult emergence was complete. A curvilinear relationship between larval weight and survival to the adult stage or to larvae in prolonged diapause is evident. The percentage of mature ova in adult females was reduced at the lower larval weights, with corresponding increases in the percentages of near-mature and large immature ova. There were linear relationships between larval weights, adult weights, and numbers of oöcytes. A method for assessing premature larval drop and other causes of mortality under field conditions is described and data for a number of years and plots are presented. Variations in the percentages of unparasitized normal late fifth-instar larvae were large. Data indicate that parasitism by Olesicampe (Holocremnus) sp. nr. nematorum (Tschek) and Bessa harveyi (Townsend) is the most important factor, probably a key factor, contributing to this variation.

Field, glasshouse, and laboratory tests showed that deposits of polyhedra of the nuclear polyhedrosis virus of the cabbage looper, Trichoplusia ni (Hübner), on foliage are practically non-infective after a 1-month exposure to weathering. Inactivation by sunlight appeared to be more important than removal by washing by rain in causing this loss of activity. The virus was readily inactivated by exposure to ultraviolet light. Virus exposed in aqueous suspensions of polyhedra or in wetted deposits was inactivated by shorter exposures than was virus in dry deposits of polyhedra.

A series of 15 embryonic stages of Periplaneta americana Linnaeus is defined on the basis of external morphological characters. These stages permit the study of internal development of embryos whose chronological age is unknown or from embryos incubated at different or varying temperatures. The stages, while extremely useful, are entirely arbitrary divisions of a continuous developmental process and a larger or smaller number of them could have been designated.

The cervical and thoracic musculature of the first-stage nymph is described for the first time, and its genesis is followed in the embryo. The embryonic and nymphal muscles are compared with those that have been reported for the adult.

A detailed taxonomic definition of the family Ironomyiidae is presented, based on both sexes of Ironomyia nigromaculata White, the only known representative. Attention is drawn to the peculiar blend of primitive and specialized conditions displayed by this species. Most of the characters discussed are illustrated and compared with homologous characters in hybotine Empididae, Platypezidae, and other groups.

Of the 21 Nearctic species of Pyrobombus Dalla Torre 11 are known to occur in southern Alberta. Distribution, macrohabitat, microhabitat, and period of nest establishment of the 11 species are compared. The behavioral patterns of camouflaging entrances to underground and false-underground hives, gathering material for nests, constructing first- and succeeding-brood egg cells, producing second-generation colonies, storing honey and pollen and producing wax, superseding intra- and inter-specifically, and mating and hibernating are compared both intra- and inter-subgenerically. Most of the behavioral patterns were common to all southern Alberta species of Pyrobombus; some were common only to certain species indicating a close relationship between these species, and one pattern was common to species in two subgenera but to only 4 of the 11 species of Pyrobombus. Thus, evolutionary trends were indicated. The enemies Psithyrus spp., Volucella bombylans (L.), and inclement weather are discussed.

Transport and dispersal of odours by air currents is considered an important factor in scolytid response to attractant sources. This viewpoint provides explanations for some puzzling field observations and data, and helps identify significant questions about scolytid flight behaviour. There is a need for "odour meteorology", which would be concerned with the rates and types of odour distribution near the ground, and would provide a basis for the most effective use of chemical attractants in natural environments.

A total of 6995 summer generation Ips confusus (LeConte) adults was reared from logs of Pinus ponderosa Laws. under laboratory conditions. Emerging adults were collected every two hours throughout the day and their sex determined. Females predominated for the first eight days but the sex ratio at the end of 40 days was 1.18 ♀, ♀: 1 ♂. High differential loss of males before reproduction is discussed. From logs attacked in the spring 62.0% of the parent adults re-emerged. Large numbers of such parents capable of reproduction could greatly increase the severity of an infestation. Spring brood emergence totaled 67.64 beetles per sq. ft. of bark surface, while summer brood emergences from two different areas were 54.50 and 33.37 beetles per sq. ft. Above 72° F., peak male emergence occurs at the 10:00 a.m. or noon collection. Females exhibit a lesser peak in mid to late morning and a major peak in mid to late afternoon, but at temperatures below 72° F. a unimodal female emergence curve becomes apparent.

Hylastes nigrinus (Mann.) is attracted to, and breeds in, the roots of both cut and beetle-killed Douglas-fir trees; the latter are preferred. The beetles reach the roots by digging through the soil. Bark samples taken from trees of various physiological condition and placed in field olfactometers showed that the beetle prefers the bark of insect-killed trees, although bark taken from healthy Douglas-firs became attractive after some time. Among the various terpenes tested, α-pinene and β-pinene were most attractive, in addition to Douglas-fir resin itself.

The Canadian and Greenlandic species of Pterocomma Buckton are described and illustrated and a key provided. This includes all but one of the known North American species as follows: bicolor (Oestlund); populifoliae (Fitch); populeum (Kaltenbach); salicis (Linnaeus); sanguiceps new species; smithiae (Monell). The phyletic position of the Pterocommatini is discussed. It is apparent that the Pterocommatini is not a primitive group of aphids.

A key and measurements are presented for the eggs of 23 species of Aedes. Twenty species from California and Nevada are illustrated, and eleven previously undescribed eggs are described.

The specific status of Neodiprion nigroscutum Middleton is firmly established by new data. The adult female is mostly black and brown. The second annulus of the lancet is generally weakly developed ventrally. The larvae have black head capsules in the first instar, but this coloration usually changes to reddish brown in the later instars. The third, fourth, and fifth feeding-instar larvae have unbroken subdorsal and supraspiracular lines, and broken postepipleural lines, but lack an epiproctal spot. The nonfeeding-instar larvae often have a pink body color. The egg mass of most females is green. Jack pine is the preferred host. The fecundity is approximately 100 eggs, but they are typically distributed over many branches, usually in one needle on each branch. Larval colonies composed of first- through fourth-instar larvae usually contain 3–10 larvae, while colonies of fifth-instar larvae usually contain 1–6 larvae. There are two generations per year in southern Wisconsin. Feeding-instar larvae are present in late May and June, and again (second generation) in August and September. The species is distributed throughout the jack pine stands of Wisconsin. Phenological data and notes on parasites are presented.

Lectotypes are designated for Cryphalus amabilis Chamberlin and C. grandis Chamberlin. The lectotypes are in the Canadian National Collection, Ottawa.