This study identifies and presents a key to five strains of the larch sawfly, Pristiphora erichsonii (Hartig), which are designated Aweme, Fernie, Ambleside, Thirlmire, and Salzburg.

Aweme and Fernie strains occur only in North America and Salzburg strain is confined to Eurasia. Two Eurasian strains, Ambleside and Thirlmire, were accidentally introduced into Canada from England by 1913 among cocoons shipped for the release of the parasite Mesoleius tenthredinis Morley. It is postulated that the ancestors of Aweme-Salzburg strains Fernie–Thirlmire strains dispersed across the Bering Land Bridge into North America some time in the Miocene. These phyletic lines evolved into distinct Eurasian and North American strains. Early infestations in North America apparently consisted of North American strains, while later outbreaks have consisted primarily of the recently introduced Eurasian strains.

Larvae of the family Chrysopidae possess characteristics useful in classification at the species, genus, and subfamily levels. This study, which initiates a comprehensive analysis of chrysopid larval systematics, describes the important external characteristics of the family and discusses those features which vary between taxa within the family.

The carnea- group of the Chrysopa, subgenus Chrysoperla, includes six described North American species, most of which are important in pest management. This paper defines the series of characters unique to the larvae of this taxon, presents a key to all larval instars of the six species, and describes the three larval instars of each species, most of which were previously undescribed.

Five new genera and 27 new species of tachinid flies from North and South America are described as follows: Acemya favilla n. sp., Actinodoria argentata n. sp., Adoryphorophaga luxatura n. sp., A. secutoris n. sp., Aphantorhapha pulla n. sp., Belvosia naccina n. sp., Calolydella summatis n. sp., Catemophrys sororcula n. sp., Chaetona pictilis n. sp., Doliolomyia n. gen. (type-species D. thessa n. sp.), D. alactaga n. sp., Echinopyrrhosia arrogans n. sp., E. pellacis n. sp., Eomeigenielloides n. gen. (type-species E. segestris n. sp.), Euceromasia sobrina n. sp., Euempheremyia melotris n. sp., Eulasiopalpus mirimodis n sp., Eutrapelus n. gen. (type-species E. atlixcoensis n. sp.), Leucostoma fallax n. sp., L. politifrons n. sp., Lindigepalpus bogotensis n. sp, Lindigia oriunda n. sp., Melanepalpus meraculus n. sp., Myioclura n. gen. (type-species M. necopina n. sp.), M. melusina n. sp., Myiophasia harpi n. sp., Technamyia n. gen. (type-species T. cinereola n. sp.), Trichosaundersia callithrix n. sp.

Changes in population density were evaluated over an outbreak cycle of the Douglas-fir tussock moth. Growth rate of populations was independent of larval density in the first year, but thereafter became a reciprocal function of density, terminated by complete population collapse at the end of the third year. Through correlation analyses, it was found that density of small larvae accounted for a large proportion of the change in population density between years. This suggests that the local infestations developed largely from resident populations of at least 2 years and not from spread of early instar larvae during the outbreak.

Parasitized and unparasitized whitefly populations were sampled on a short-term crop (poinsettia) at 4–7 day intervals until crop harvest. Age-specific whitefly survivorship and parasite activity were evaluated in relation to various biotic and abiotic factors. Three critical factors influenced the outcome of the whitefly–Encarsia formosa interaction during short-term crop production. Commercially acceptable levels of control were achieved on poinsettia by (a) introducing parasites during the first 40 days of crop production, as pupae, when small scales were abundant, (b) introducing sufficient parasite pupae to develop a ratio of one adult parasite for every 30 large whitefly scales, and (c) maintaining an average temperature of 23.3 °C (74°F).

The mechanism of sperm precedence in the spruce budworm was studied using a genetic marker. When female moths with red-eyes, a recessive trait, are mated twice within a day, first with a red-eyed male followed by a black-eyed male, three types of offspring were observed in the F1 generation. Some females produced only red-eyed offspring; another group produced only black-eyed progeny; a third group produced a mixture of both types. This indicates that sperms received from either or both matings may be utilized. The time interval between successive sperm transfers appears to be the underlying factor that determines sperm precedence in this insect; a hypothesis to explain this phenomenon is presented.

A sex-linked mutant of the tobacco budworm, Heliothis virescens (F.), has been isolated. The wild-type pupae are brown, and the mutant pupae are yellow-bodied. The mutant (yb) could aid in sexing large numbers of tobacco budworms since > 98% of the female pupae from ± ♀ × yb/yb ♂ are yellow but all male pupae are brown. Data on mating frequency, fertility, and F1 survival of six mating types between ± or yb females and yb/yb, ±/yb, or ±/± males indicate that selection favors the wild-type genotype. When heterozygous males were crossed with either female genotype, the effect on fertility was similar to that produced by homozygous mutant males. Also, when heterozygous males were crossed with mutant females the effect on mating was similar to that produced by homozygous males. However, when heterozygous males were crossed with wild-type females, mating frequency was intermediate between that of the homozygous mutant and that of the homozygous wild-type. Survival of larvae from mutant females was lower than survival of larvae from wild-type females.

Aggressive behavior of the western cherry fruit fly studied both under laboratory and field conditions indicates that males are extremely territorial, especially in the field, where they do not tolerate the presence of another fly on a cherry unless the invader is a mating partner. Under confined laboratory conditions, the sense of territoriality was markedly reduced. Aggressive behavior in this insect included a wing jerking display, head-on collision, and "boxing" (fight involving prothoracic legs).

Metrioptera (Roeseliana) roeselii (Hgb.) was first introduced into the Montreal, Que., area before 1952. By 1965 it had been collected in western and southern New York State. This paper records it from Maine, Massachusetts, and New Hampshire for the first time, and discusses the populations. Eventual establishment of M. roeselii over all of New England is predicted.

The mountain pine beetle, Dendroctonus ponderosae, and 68 associated insect species were reared from infested sugar pine, Pinus lambertiana. Portions of three infested trees were sectioned by height and the insects emerging from each were identified and recorded. In one tree the number of woodpecker strikes also was noted. The tops of two of the three trees were infested by another bark beetle, Pityophthorus confertus, and from these same two trees the most common parasite obtained was Macromesus americanus.

Studies on the damage and losses of wheat crop caused by the migratory grasshopper, Melanoplus sanguinipes (Fabr.), were carried out under field conditions during 1972 and 1973. A significant inverse relationship was evident between grasshopper density and grain yield. Loss in yield may occur due to grasshopper infestation in different ways: (1) early hatching of grasshoppers may completely destroy newly-germinated seedlings; (2) a gradual defoliation of the crop throughout the growing season reduces yield and grade of the seed due to reduction of plants’ photosynthetic efficiency; (3) headclipping occurs towards the end of the season when leaves have been completely destroyed. The role of weather factors in shaping the impact of grasshoppers on the crop is discussed.

In 1966, Ueno described and figured a nymph as Ephemerella sp. from a series of 12 specimens collected by the Kyoto University Pamir–Hindukush Expedition in 1955. Allen (1971) named this mayfly E. borakensis from Ueno's description and figure, and placed the species in the subgenus Drunella Needham.

Pemphigus spirothecae Passerini, a member of the subfamily Eriosomatinae, was collected in large numbers from spiral galls on lombardy poplars in Quebec during 1972 and 1973. This aphid is well known in Europe but has not been reported previously from North America. It has a monoecious life cycle.