Sexupara production in the pear root aphid, Eriosoma pyricola Baker & Davidson, was closely associated with the cessation of shoot growth of its host in the field in irrigated and non-irrigated plots in two successive, but phenologically different years. Neither the environment nor the host plant were unfavorable at the time the sexuparae were formed, indicating that the aphid uses the host plant as a source of seasonal information.

The nature of synchronization between active development of univoltine insects and trees is discussed. It is concluded that the initiation of dormancy in trees and diapause in insects is not likely to be synchronized by a common set of environmental factors. Either regulation of insect diapause by host trees is more common than is currently recognized, or environmental and age differences in tree growth have favored selection for obligate diapause.

The genus Euderus Haliday in America north of Mexico consists of five subgenera, Secodelloidea Girault, Euderus Haliday, Euderoides n. subgen., Neoeuderus n. subgen., and Leipocrossus n. subgen. and 25 species; 13 species are described as new and are as follows: Euderus (Secodelloidea) canadensis, E. (Euderoides) purpureus, E. (Neoeuderus) viridilineatus, E. (Neoeuderus) magnificus, E. (Leipocrossus) californicus, E. (Euderus) solidaginis, E. (Euderus) vockerothi, E. (Euderus) chillcotti, E. (Euderus) masoni, E. (Euderus) fuscedinellae, E. (Euderus) pecki, E. (Euderus) glaucus, and E. (Euderus) alaskensis. Species groups of albitarsis and solidaginis form two natural groupings within the genus Euderus s. str. Keys to subgenera and species, distribution, and host records are included.

The phylogenetic relationships between species groups and subgenera in the Forcipomyiinae are presented for the first time, from a consideration primarily of male genitalic structures and comparative morphology of all stages. A dendrogram showing the phylogenetic relationships within the subfamily and a figure showing the evolutionary trends in claspette development in the subfamily are given.The genitalia of Atrichopogon are considered as plesiomorphic and the genus a possible living prototype of all Ceratopogonidae.

It is proposed to consider the taxon Leptochironomus Pagast as a genus which includes: L. tener (Kieffer), L. aegyptius (Kieffer), L. stilifer (Freeman), and L. deribae (Freeman). L. paraderibae La ville and Tourenq is regarded as a synonym of L. deribae.The juvenile stages of L. stilifer are described. The opinion is expressed that the juvenile stages described as Chironominae genuinae No. 4 (Lipina 1927), Microchironomus conjugens Kieffer (Lenz 1926), and Microchironomus No. 1 (Zavrel 1931) belong to Leptochironomus.

Females of Nemeritis canescens (Grav.) were conditioned to associate the odour of geraniol with the presence of hosts. Females conditioned for 10 days retained the conditioned response for 6 days. Associative learning in N. canescens, an oligophagous parasite, is less strong than in Itoplectis conquisitor (Say), a polyphagous parasite. This finding may reveal a general difference between oligophagous and polyphagous parasites.

Studies were conducted in southern Oregon pear orchards to develop sampling methods for assessment of mite abundance. Those species included in the investigation were the two-spotted spider mite, Tetranychus urticae Koch; European red mite, Panonychus ulmi (Koch); yellow spider mite, Eotetranychus carpini borealis (Ewing); and the predaceous phytoseiid Typhlodromus occidentalis Nesbitt.The results show that five leaves on one limb per tree are adequate to include representative numbers of the four mite species. Variation in mite densities between trees, even of the same variety, was quite high. The sample size (numbers of trees) required for assessing mite density can be calculated provided that an estimate of the coefficient of variation (S/X) is available.

Larvae of the dark-sided cutworm were collected from trap plants of tobacco set in a field of rye at Delhi, Ont., in 1969. They were reared individually to pupation to determine the degree of survival and the causes of mortality from the fourth instar to maturity. About 36% pupated and the greatest amount of mortality was caused by insect parasitism, a microsporidial disease, and bacterial infection. Fungus and virus diseases were virtually absent. As adult females are capable of laying a large number of eggs, mortality in eggs and young larvae must reach at least 98% to maintain a stable population. Introduction of virus pathogens to attack larvae might well be expected to result in regulating the population at a lower density.

The amount of sweet-fern was significantly related to the degree of Saratoga spittlebug adult injury to red pine on study plots in Lower Michigan. Other host plants supporting spittlebugs must be extremely abundant before populations increase enough to cause heavy injury. A spittlebug risk-rating device is presented that specifies hazard in a red pine stand by plotting per cent sweet-fern against per cent other suitable hosts.

The palpus of a fossil crab spider, Xysticus archaeopalpus new species, is described. It was found in peat beds of the Lava Camp Mine near Deering, Alaska. This species belongs in the loculpes group, and is closely related to the extant species, Xysticus britcheri Gertsch. The peats are overlaid by basalt dating 5.7 million years old by the K/Ar method. Regional and local paleo-environmental conditions, based on evidence provided by plant and insect fossils, are discussed.

Evidence is presented indicating that Harnischia Kieffer in the sense of Lenz is correct. Harnischia sensu Beck & Beck then becomes a synonym of Cryptocladopelma Lenz (which, however, is formally a nomen nudum). Synonyms of the genus Harnischia are given. Corrections and additions to the descriptions of Harnischia curtilamellata (Mall.) (syn. H. pseudosimplex Goetgh. syn. nov.) are given. The genus Harnischia is characterized. The phylogeny of the Harnischia complex is discussed.

Abatement programs for nuisance species of Trichoptera at Fort Erie, Ont., and Montreal, Que., are compared and attempts are made to determine why the former was successful throughout 16 consecutive years but failed in the 17th, whereas the Montreal project was not successful in its initial test. In both, DDT was used as a residual insecticide in the resting places of the adults. It is suggested that DDD (TDE) be considered as a substitute for DDT if a relatively waterproof, residual insecticide is required for this specific purpose.

An anatomical description of the larval and pupal stages of the genus Conophthorus Hopkins is given and illustrated. The description is based on larvae of nine species and pupae of eight, but the strong similarity in all anatomical details suggests that the description will probably cover the remaining species. The most recent addition to the genus, C. banksianae McPherson, is referred to particularly, and the need for a complete revision of the genus is suggested.

Annual changes in genetic quality were measured in natural populations of Hyphantria cunea Drury for 12 years in New Brunswick and Nova Scotia. Models for heritability and natural selection pressure, derived independently from experimental data, are used to simulate the changes in quality over the same period. In seven of eight areas, observed and simulated trends are significantly correlated. Regressions between observed and calculated values, examined with respect to both means and slopes, suggest how these preliminary models may be refined. The influence of genetic changes on the natural regulation of population density is discussed briefly, but analysis is deferred to a later paper in this series on H. cunea.

Larvae of Neodiprion swainei Midd. were reared to the adult stage under controlled conditions of temperature and photoperiod. The effects of temperature are particularly evident during the larval stage, cocoon spinning, and adult emergence and are also observed through variation in cocoon weight and fecundity. Feeding, fecundity, and diapause are directly related to photoperiod. Larvae eat more when the photophase is long, an effect that is detrimental to the organism because there is a parallel loss of energy expressed in the number of day-degrees required to complete development.

The flour mill insect, Cyrptolestes turcicus (Grouvelle), was reared on seven diets at 28 ± 1 °C and at relative humidities of 90% and 60% as follows: flour from a mill previously infested with C. turcicus, commercial flour sterilized with propylene oxide, unenriched commercial flour, and four laboratory-prepared diets each containing a different concentration of fungi isolated from the previously-infested flour.

At 90% relative humidity, larvae developed fastest on the infested flour and on the prepared flour–fungi diets, and slowest in sterilized flour. Fungal concentration and rate of larval development were inversely correlated. The highest survival of larvae occurred on the flour–fungi diets and the highest mortality on the flour from the infested mill. There was no clear relationship between rate of pupal development and concentration of fungus. Of the prepared diets, that with the largest concentration of fungus promoted the fastest rate of pupal development. Survival of pupae was about 20% higher on the flour–fungi diets than on the sterilized flour. At 60% relative humidity about 50% of larvae and pupae survived and completed development on the flour–fungi diet containing 1% by weight of fungi, and on the flour from the infested mill but none survived on any of the other diets. Sixty per cent of larvae and 83% of pupae survived and developed on the flour from the infested mill. None of the larvae survived on any of the other diets.

A simple method for separating and surface sterilizing spruce budworm eggs is described. The egg masses are incubated with constant agitation in a 1% solution of NaOH for 10 minutes at 35 °C. The separated eggs are rinsed serially in distilled water, 1% bovine albumen solution, and 70% ethanol, and placed on a moist, sterile filter paper in a petri dish. When surface sterilized eggs are not required the 70% ethanol wash can be omitted.

Two new species of Platygaster accounting for high rates of parasitism in balsam gall midge are described. These appear to be widely distributed within the range of balsam fir in North America.

The trombidiid subfamily Neotrombidiinae Feider is re-established and redefined, based primarily on larval characters but also on adult characters. It is closely related to the trombidiid Trombellinae on the one hand and to the Leeuwenhoekidae on the other. It consists of two genera, namely Monunguis Wharton, which is monobasic and known only from the larva, and Neotrombidium Leonardi, with 13 described species of which 7 are known from the larva and 8 from the adult (the larva and adult of 2 species are correlated by rearings).The history of the family-level placement of this group, and the controversy over whether or not to recognize two genera, are reviewed. The characters that justify the separate recognition of Monunguis and Neotrombidium are enumerated.The larva of each of the following species of Neotrombidiinae is described, illustrated and keyed: Monunguis streblida Wharton from the Caribbean area, Neotrombidium barringunense Hirst from Australia, N. tricuspidum Borland from North America, N. tenuipes (Womersley) from Malaya, N. samsinaki (Daniel) new combination from central Europe, N. anuroporum new species from Central America, N. bengalense new species from India, and N. tenebrione new species from eastern North America. Six other species of this group, known only from the adult, are listed separately but are not treated taxonomically here.The larvae of Neotrombidiinae parasitize adult insects: those of Monunguis are hyperparasites on streblid flies whereas those of Neotrombidium are ectoparasites of cerambycid, clerid, elaterid, and tenebrionid beetles that pass part of their life history under the bark of trees.In the Microtrombidiinae, Camerotrombidium Thor is noted as the valid replacement name for the preoccupied Ottonia Kramer.