The developmental stages of Sulphuretylenchus elongatus, an abundant nematode parasite of Scolytus ventralis, are described. The life cycle was generally synchronized with its host, nematode reproduction usually occurring in the adult beetle after it had attacked a new tree. Reproduction occasionally occurred in the host larva. In these cases encapsulation of some nematode eggs and larvae was observed and the host usually died. Free-living infective stage nematodes emerged from the host, mated in the bark beetle galleries, and the female nematode reinfected bark beetle larvae by penetrating the cuticle.Parasitism by S. elongatus caused delayed emergence, limited flight, and aberrant attack behavior by infected S. ventralis. Female bark beetles were sterilized by heavy infection and partially sterilized by light or moderate infection. The effects of parasitism on males was not as severe. Some egg and larval mortality was attributed to nematode attack, and adult survival was reduced by infection.Parasitism was slightly higher in female bark beetles. The incidence of parasitism decreased somewhat in the upper levels of the tree. Host density appeared to have little effect on per cent parasitism although the degree of super-parasitism increased with host density.

Nepticula macrocarpae Freeman, a recently described leaf miner on oak in southern Ontario, is bivoltine, and overwinters as a cocooned larva on the ground. The immature stages are described and nine species of chalcid parasites are listed.

Methanol, acetaldehyde, and ethanol have been identified in extracts of attractive wood and bark. The attractancy induced by anaerobic treatment in both sapwood and phloem of conifers and broadleaf trees was characterized by ethanol as the most concentrated component. In laboratory bioassays, ethanol was attractive at low concentration to both sexes of Trypodendron lineatum (Olivier). Methanol and acetaldehyde, at the concentrations found, apparently play no role in attraction. Monoterpenes had a repellent effect on T. lineatum.

Egg production in Neodiprion swainei may be severely reduced by food quality and quantity, tachinid parasitism, and prolonged diapause. Since these and other agents may affect the sawfly both lethally and sublethally and may operate differentially against males and females, population losses are not adequately expressed in terms of numbers of individuals. However, reduction of the potential number of eggs the population could produce provides an integrated measure of these effects. One example, from an experiment in which larvae were fed various quantities and types of foliage, demonstrates that loss of reproductive potential is several times as great as the loss of individuals and indicates that the latter seriously underestimates the importance of food in population events.Cocoon diameter and fecundity are closely related. In a Saguenay Valley population, fecundity, cocoon diameter, and deviations from the regression line were bimodally distributed, indicating a mixture of two types of individuals differing in egg production characteristics. Families within a single population differed from each other by as much as 14 eggs in the elevation of the regression line; this was more than the observed difference in elevation between populations. A single regression equation satisfactorily predicted fecundity in one Quebec and a Wisconsin population, but was unsuitable for two other Quebec populations, each of which required its own equation. Among insects of common size, mean egg length varied inversely with fecundity, but it is uncertain whether differences in egg size were responsible for variation in the fecundity-cocoon diameter relationship.

The proportion of females of the European red mite, Panonychus ulmi (Koch), reared from periodic samples of larvae and nymphs from a peach orchard averaged about 75% with little seasonal variation. A male can copulate at least 11 times in 2 hr, and inseminate at least 26 females during its life span, but many later copulations inseminate the females incompletely or not at all. Some females copulate at least three times but one copulation with a young male enables a female to lay the usual proportion of fertilized (female) eggs, which exceeds that of unfertilized (male) eggs. No evidence of males with only one nymphal instar, as reported in Europe, was found in mites reared at 15°, 22°, or 30 °C. Males disperse much more rapidly than females.

The cephalic structures of the final instar larva of 278 species of 140 genera of Braconidae were examined. On the basis of these and biological data, modifications are proposed in the classification of the higher categories. Zele (Helconinae) and Eubadizon (Blacinae) are placed in the Macrocentrinae (endoparasites of larval Lepidoptera) and Meteoridea is moved from the Helconinae and ranked as an independent subfamily. The Blacinae is completely dismembered: Aliolus, Triaspis, Urosigalphus, Blacus, and Calyptus form a tribe of the Helconinae (endoparasites of larval Coleoptera); Microtypus, Orgilus, and Stantonia form a tribe of the Agathidinae (endoparasites of larval Lepidoptera); and Pygostolus, Centistes, and Syrrhizus a subfamily near Euphorinae with Cosmophorus (endoparasites of adult Coleoptera). Present genera of Microgasterinae are separated into two tribes with the addition of the Cardiochilini as a third tribe. The Dacnusinae is reduced to a tribe of the Alysiinae. The Rogadinae is reduced to one tribe, Rogadini, containing only Rogas and allied genera (endoparasites of larval Lepidoptera). Rhyssalus is transferred to the Hecabolini, and Exothecini, Pambolini, Hormiini, and ectoparasitic Rogadini to the Braconinae (ectoparasites of larval Coleoptera, Lepidoptera, etc.). The problematic genus Gnaptodon is also placed in the Braconinae.

Fossil puparia from the Edmonton Formation (Upper Cretaceous, about 70,000,000 years) at Drumheller, Alta., are assigned to the family Calliphoridae and described as Cretaphormia fowleri new genus, new species. This is the first pre-Tertiary record of muscoid flies.

The Palaearctic species of Iziphya Nevsky are revised and the following species recognized: austriaca Borner, bufo (Walker), fungifera (Ossiannilsson), ingegardae Hille Ris Lambers, leegei (Börner), maculata Nevsky and oettingenii Quednau. Iziphya memorialis Börner and piluliferae Quednau are considered synonyms of bufo. Nevskyella Ossiannilsson and Juncobia Quednau are considered synonyms of Iziphya. A key to the world fauna is offered.

Intensive studies on the population dynamics of the birch leaf miner, Fenusa pusilla (Lepeletier), were carried out in two stands of blue birch at the Morgan Arboretum, Macdonald College, Que., from 1964 to 1966. Life tables for nine and two generations, respectively, showed that mortality of the immature stages was lower on 3- to 5-year-old trees than on 9-year-old trees. The analysis of successive age-interval survivals in relation to generation survival revealed that predation during the late larval stages was the key factor in generation survival of the insect on the younger trees. Desiccation of the leaf during the early larval stages along with predation were key factors on the older trees.

Varying degrees of ovarian development were induced in overwintered Dendroctonus pseudotsugae Hopk., put on (1) host logs, (2) bark chips, or (3) moist glass paper. In 96 hours the ovaries of beetles on logs reached maturation, those on bark chips showed only slight growth, and the third group failed to show any development.Farnesyl methyl ether induced significant ovarian development in beetles kept on bark chips or glass paper. It appears that production or release of gonadotrophic hormone is withheld in insects kept outside their natural gallery environment. Sensory input associated with gallery excavation may initiate ovary development by stimulating endocrine activity.

Effects of temperature and resin on hatch of mountain pine beetle eggs were investigated. Per cent hatch was related to total degree-hours above 40°F, the average being 5113 for 50% hatch under field conditions. Average supercooling point was 1.3°F. Higher temperatures in the freezing range were lethal with long exposure. Atmosphere saturated with volatiles from liquid resin had very little effect on egg hatch, but direct contact with liquid resin greatly reduced egg hatch.

The larva and pupa of Glutops rossi Pechuman are described. Because of their remarkable similarity to the same stages of Pelecorhynchus Macquart, as well as many similarities in their adults, the genus Glutops Burgess is transferred from the Xylophagidae to the Pelecorhynchidae.

The possible origin and site of introduction of Berytinus minor (H.-S.) (Hemiptera: Berytidae) into North America are discussed and new North American records given. B. minor exists in both a long winged (macropterous) and short winged (brachypterous) form. Differences in morphology of the pronota and wings of both forms are given and compared with a description of the differences found in the literature. Inapplicability of the terms macropterous and brachypterous as applied to B. minor is discussed. Notes on biology and ecology at Ithaca, N.Y., are given. The species appears to overwinter as an adult and to disperse in April to its food plant, white clover, Trifolium repens. Mating and oviposition begin in late April and May with the adults of the season maturing in late July or August.

The larvae of the following species of Dytiscidae are described and figured: Laccophilus maculosus (Germ.), L. biguttatus Kirby, Liodessus affinis (Say), Hydroporus notabilis Lec, Hygrotus punctilineatus (Fall), Hyg. tumidiventris (Fall), Hyg. punctatus (Say), Hyg. patruelis (Lec.), Hyg. impressopunctatus (Schall), Hyg. canadensis (Fall), Hyg. sellatus (Lec.), Laccornis conoideus (Lec.), Rhantus notatus Fab., Colymbetes sculptilis Harr., Agabus clavatus Lec., A. discolor Harris, A. bifarius (Kirby), A. ontarionis Fall, Graphoderus zonatus (Hoppe), Acilus semisulcatus Aubé, Hydaticus stagnalis (Fab.), Dytiscus sublimbatus Lec., D. dauricus Gebler, and D. fasciventris Say. All were collected at Delta, Man.

Dendroctonus rhizophagus sp. n. collected from small pine trees in Mexico is described. Notes on seasonal development and habits are given.

A female Priacma serrata (LeConte) was collected near Procter, B.C., and kept alive for 63 days. It mated and produced 1,463 eggs. Egg and first-instar larva are described briefly.

Agrypon is distinguished from other genera and is discussed in relation to Trichonotus. A new species is described, and A. alaskensis Ashmead is synonymized with A. provancheri (Dalla Torre).

Biology of the red-backed cutworm, Euxoa ochrogaster (Guenée), was studied in the laboratory to provide new knowledge and for comparison with other cutworm species. The eggs possessed a moderately severe diapause that was terminated more quickly at 5 °C than at higher and lower temperatures. Intensity was related to temperatures of incubation. The eggs were fairly resistant to desiccation. The duration of development of embryos, larvae, and pupae varied inversely with temperature. A diurnal rhythm occurred in emergence of moths from pupae and during oviposition; more than 60% emerged and 85% or more eggs were laid during the night period. Moths mated in the dark. Multiple matings were common, ranging from one to seven and averaging two or three. Egg development at emergence was rudimentary but it accelerated with age after emergence. The preoviposition period in the laboratory averaged 8 days. The mean oviposition per female was 411 and ranged from 251 to 705. Maximum longevity of both sexes was approximately 20 days.

The parasites known to attack the black-headed budworm in Alaska and the relative importance of each species are presented. A key for the identification of parasite adults and notes on the bionomics of each species are given. The list of parasites includes 16 species, contrasting sharply with the 48 species reported from coastal British Columbia. Only two species, Triclistus pallipes Holmg. and Meteorus argyrotaeniae Johansen, appear in the Alaskan complex that do not also appear in the list from British Columbia. Trichogramma minutum Riley, the only egg parasite, caused up to 22% mortality. Four species attacking various larval instars caused 2 to 72% mortality within single larval collections. Two pupal parasites, Itoplectis quadricingulatus (Prov.) and Phaeogenes arcticus Cush., were reared from 10 to 31% of pupae collected in the field.