Populations of the western spruce budworm, Choristoneura occidentalis, were sampled in western Montana, central Idaho, and eastern Oregon. In 22 of 24 populations, the proportion of females among pupae did not differ from 0.5. Similarly, in 21 of 24 populations, the proportion of females among adults was not different from 0.5. In all populations, differences between survival rates of male and female pupae were attributed to chance. The proportion of females among pupae (a) did not differ between insects on Douglas-fir and those on grand fir, (b) was slightly but significantly higher among insects in the mid-crown than among those in the lower crown, and (c) was significantly higher among the insects in the one site studied where average defoliation of current-year shoots was greater than 50%. Variation in the proportion of females among adults should have a negligible effect on the dynamics of these populations.

The dosage–mortality relationship of a multi-embedded nuclear polyhedrosis virus was determined for each instar of the bertha armyworm by probit analysis of mortality following the ingestion of polyhedral inclusion bodies (PIBs) placed on the surface of an artificial diet. Susceptibility to infection decreased as larvae aged; the median exposure doses (LE50) increased from 18 PIBs/larva for the first larval instar (L1) to 21 × 106 PIBs/larva for half-grown L6. When given equivalent doses, the time for infected insects to die increased with the age of the larvae. Within any given instar the length of time to death shortened with increasing doses. Larvae that survived to become adults showed no signs of infection. There was no evidence that any infected individual could recover from infection. From the data presented, calculations show that maximum production, 2.90 × 109 PIBs/treated insect, is achieved by feeding 10,000–20,000 PIBs/larva to young L5. Larvae dying as L6 have about 40% of their normal dry weight of essential tissue converted to PIBs. Although this MNPV currently would not be cost effective as a spray for protecting crops from bertha armyworm damage, its potential as a biocontrol agent, applied in small amounts at an early stage in bertha armyworm outbreaks, should be evaluated.

The North American species of the genus Olophrum Erichson are revised. Seven species are recognized, the holarctic species O. latum Mäklin, O. boreale Gyllenhal, O. consimile Gyllenhal, and O. rotundicolle C. R. Sahlberg; the eastern North American species O. obtectum Erichson, and the new species O. cascadeuse known from northern California and eastern Oregon and O. idahoense known from southern Idaho.

Lectotypes are designated for O. marginatum Mäklin (= O. consimile), O. parvulum Mäklin (= O. consimile), O. convexum Mäklin (= O. rotundicolle), and O. convexicolle LeConte (= O. rotundicolle). The following new synonymy was established: O. bernhauerianum Scheerpeltz, O. recticolle Scheerpeltz, O. recticolle curtipenne Scheerpeltz are synonyms of O. consimile; O. quesneli Hatch is a synonym of O. boreale; and O. brevicolle Bernhauer is a synonym of O. latum. All species are described and illustrated with scanning electron photomicrographs and line drawings, five maps showing the North American distribution of each species are provided, and a key is presented to aid in the identification of the species. All available records and biological data for the species are provided.

Eight species of Epidamaeus of arctic western North America and extreme northeast, U.S.S.R. are discussed. Two new species, Epidamaeus hammerae and E. tritylos, are proposed and E. arcticolus, E. kodiakensis, E. mackenziensis, E. bakeri, E. coxalis and E. fortispinosus, previously described by Hammer, are redescribed.

Pupae of winter moth, Operophtera brumata (L.) (Lepidoptera: Geometridae), from southwest England were subjected to nine temperature treatments in the laboratory. The pupal period of about 180 days was unaffected by changes in mean temperatures between 9.5 °C and 16.8 °C. Adult emergence was delayed at a mean temperature of 17.7 °C; no pupae survived at mean temperatures above this. These results are compared with conflicting statements in the literature about the relationship of length of the pupal period with temperature.

No pupae died when exposed to temperature cycles of 20°–25 °C in the early part of the pupal period. The same temperatures near the time of adult emergence caused increased mortality. The duration of the pupal period was unaffected by exposure of pupae to 12 h (rather than diurnal) temperature cycles.

Fourteen new records of introduced leafhoppers are added to the 157 leafhoppers previously recorded as occurring in both the Old and New worlds. Of these, 62 were erroneously recorded previously although 12 of the European species subsequently have been found in North America. Two North American species have been introduced into Europe, and one European species has been found in South America; North America has received 61 species from Europe, 3 from Asia, and 1 from Africa. One pan-tropical species is probably a recent introduction into the Caribbean from the Old World. There are 30 transboreal leafhoppers, 5 transarctic species inhabiting the tundra and alpine meadows, and 9 inhabiting temperate regions of both Eurasia and North America.

The Aster leafhopper (Macrosteles quadrilineatus Forbes) is removed from synonymy with the transboreal sedge-feeding M. fascifrons (Stål) and 25 other confused species are distinguished in the genera Aphrodes, Euscelis, Evacanthus, Limotettix, Macrosteles, and Typhlocyba. These include 11 new species: Evacanthus bellaustralis, E. chlamidatus, E. grandipes, E. lacunar, E. nigramericanus, E. ustanucha, Macrosteles lagus, M. severini, M. tesselatus, M. vilbastei, and Typhlocyba frigida, all from North America, Balclutha punctata confluens Rey and Limotettix striola ferganensis Dubovsky are elevated to species status. One new generic synonymy, 23 new specific synonymies, and 3 new combinations are created.

A comparison of the seasonal biology of Thymelicus lineola at Normandin and Joliette, Quebec from 1974 to 1976 showed marked differences between regions for the same year, and within regions for consecutive years. These data together with constant temperature development information were used to develop a predictive phenological model for this insect, which was then validated using independent data sets collected between 1976 and 1981. Good agreement between observed and predicted values were obtained. The usefulness of the model in predicting optimal spraying dates was tested at Amqui and Normandin, Quebec in 1982. Accurate predictions were obtained at least 2 weeks in advance, sufficient for use in a management programme.

The role of Leucopis sp. nr. albipuncta larvae in controlling outbreaks of the apple aphid, Aphis pomi De Geer, was studied in five New Hampshire orchards. There was significant correlation of larval density with changes in the density of apple aphid populations, and larvae were widely distributed throughout the apple growing region of the state. The egg, three larval instars, and puparium are described and illustrated.

The genus Oethecoctonus of North America is revised. Three species are recognized, of which two are new to science: O. ophrynopus and O. pleuralis. O. oecanthi (Riley), the type-species of the genus, is redescribed and figured. A generic diagnosis of Oethecoctonus and key to North American species are given. The higher classification and world distribution of Oethecoctonus species are discussed.

In laboratory trials, the susceptibility of Aedes euedes Howard, Dyar and Knab and Aedes stimulans (Walker) larvae to temephos (Abate®), was positively correlated with increasing temperature. Early instar larvae were more susceptible than late instars. Susceptibility differed 36 times from the fourth instars at 4 °C (24 h LC50 = 16.92 ppb) to the first instars at 19 °C (24 h LC50 = 0.47 ppb) the extremes of instar and temperature tested. The minimum recommended dosage of temephos (6 ppb) was ca. 9 times the LC90 of first instar A. stimulans and A. euedes at 19 °C. By contrast, the 24 h LC90 of 67.4 ppb for the fourth instar of A. stimulans at 4 °C was ca. 4 times the maximum concentration of temephos (18 ppb) currently recommended for Aedes spp. control. However, in simulated pool studies, satisfactory control of A. stimulans was achieved by 72 h posttreatment at the highest recommended dosage.

Emerging Trichoptera were collected from the littoral zone of a newly-created reservoir, Southern Indian Lake, Manitoba, from 1977 to 1981. The relationship between caddisfly emergence and lake shoreline type, depth of sampling, and shoreline erosion rate was studied. Twenty-five species of Trichoptera were collected; six species of Polycentropodidae comprised almost 75% of the total number of individuals. Abundance and richness of Trichoptera were correlated with shoreline stability, with higher abundance and richness being found at more stable (i.e. lower erosion) shorelines. Highest numbers of Trichoptera emerged in 1981, 5 years after impoundment. Maximum abundance and richness of Trichoptera was found at 3.5 m depth, which is also the depth at which maximum deposition of organic matter occurred. Agrypnia straminea Hagen, a case-maker, dominated the trichopteran fauna at the marsh shoreline; species of net-spinning Polycentropodidae dominated at the clay shorelines. Patterns of species composition and abundance in 1982 artificial substrate collections were similar to those found in 1977–1981 emergence trap collections. Interspecific differences in Neureclipsis capture nets may explain the greater abundance of N. validus (Walker) than N. bimaculatus (L.) at a high erosion shoreline.

A method was developed for the transfer of intact medium-sized Dolichovespula arenaria colonies from their original locations, without damage to the nest and with minimal narcosis of the adult wasp population. The method necessitates a substantial manipulation early in the course of colony development, after which the nest is left to develop normally in situ until it is sufficiently populous to permit tranfer to a new location without intolerable loss of adult insects. We describe also a system for housing vespid colonies following relocation, together with a one-way tunnel system which has proved efficient for the purpose of collecting data on foraging activity.

Megagrapha Melander and the four other New World genera named below are defined as a natural group which belong to the tribe Drapetini of the subfamily Tachydrominae. Both the genus group and the component genera are described and keys to genera and species are presented. One new genus, Chaetodromia Chillcott from Mexico is described, with two new species. One new species is described in Megagrapha, five in Austrodromia Collin, four in Allodromia Smith, and 17 in Micrempis Melander. Micrempis testacea Melander is transferred to Allodromia, and Allodromia curviradius Smith is transferred to Micrempis. Megagrapha exquisita (Malloch) is resurrected from synonymy as a valid species. Lectotypes are designated for Micrempis minuta (Melander), M. nana Melander, and M. varipes Melander.

The genus Gryon Haliday in North America is revised. Twenty-seven species are recognized, 12 of them new to science: G. aculeator, G. acutiventre, G. atrum, G. chelinideae, G. elatior, G. longipenne, G. obesum, G. radiculare, G. stewarti, G. triangulum, G. vitripenne, and G. xanthosoma. The tribe Gryonini is discussed, and a key to North American genera of the tribe is included. A generic diagnosis of Gryon is given, and seven species-groups are discussed and(or) proposed. A key, diagnoses, relationships, and bionomics of species in North America are given. New terms for additional characters found on the posterior surfaces of the head are defined and figured.

Intrapopulation size variation was studied by means of length measurements quoted in taxonomic literature and from material of various groups of Coleoptera collected in the field. The degree of variation was significantly different among groups, and generally the free-living groups had lower intrapopulation size variation than most of the tree-boring and the parasitoid groups. Several tree-boring groups (e.g. Scolytidae, Curculionidae), however, had a comparatively low variation. A high intrapopulation size variation is common in species whose larvae are unable to choose and determine their own nutritional situation. Such larvae have a restricted mobility and the quality of their food is unpredictable. This is characteristic for most of the tree-boring groups. A high size variation increases the niche width of the species and probably has a buffering effect in unpredictable environments. Those tree-borers that are able to reduce the degree of unpredictability (i. e. by parental care, specialization in choice of microhabitat and in larval morphology, as in Scolytidae) have a rather low intrapopulation size variation. There are two possibilities regarding the genetic nature of the high size variation: (1) The population contains a variety of phenotypes with genetically fixed size, and (2) each individual is flexible with the possibility of becoming large or small depending upon the nutritional conditions. Possibility (1) is in agreement with the theories of a correlation between environmental heterogeneity and a high intrapopulation genetic variation. Free-living species and those tree-borers with less intrapopulation size variation are usually subject to more uniform conditions, and if adverse conditions do arise, these species usually fail to complete their development rather than produce smaller adults.

Local dispersal and survival of male spruce budworm, Choristoneura fumiferana (Clem.), moths under field conditions was determined by mark, release, and recapture in pheromone-baited traps. Recapture rates and distance of recapture were dependent upon height of traps and proximity of traps to the release point, but over 65% of those recaptured were caught within 50 m. With traps 20 m apart, 30% of the recaptures were in traps farthest from the release point (50–70 m), a fact which suggests that male spruce budworm may disperse beyond this distance at low densities. Males were recaptured up to 7 days after release, and had a daily survival rate averaging 67%.

The Nearctic species of the genus Trichacis are revised. Nine out of 15 species recognized are new to science: T. alticola (New Mexico, Colorado), T. bison (Ontario, Florida, Louisiana, Illinois, Texas), T. celticola (Mississippi, Ontario, Louisiana, Texas), T. dracula (Illinois), T. elongata (Missouri), T. huberi (California), T. mandibulata (Illinois), T. pyramidalis (Ontario), and T. striata (Florida). Six previously described Nearctic species are redescribed, viz. T. arizonensis (Ashmead), T. cornicola (Ashmead), T. cornuta Fouts, T. rufipes Ashmead, T. texana Fouts, and T. virginiensis Ashmead. The males of T. arizonensis, T. texana, and T. virginiensis are described for the first time. A generic diagnosis of Trichacis and keys to Nearctic species are given. The higher classification, bionomics, world distribution, and character states of Trichacis species are discussed.

Studies showed that the type of damage, the timing of damage with the phenological stage of the crop, and the amount of available soil moisture influenced the growth response of spring wheat to acute levels of grasshopper damage and acute levels of artificial damage. Ground-level cutting of plants resulted in the greatest reduction in plant biomass and crop yield, while grasshopper damage and artificial stripping of leaf material did not result in as severe a reduction in either biomass or yield.

Damaged plants were not able to recover lost biomass when damage occurred any later than the early stages of tillering despite observed relative growth rates which were higher than control plants. The greatest degree of recovery occurred in study sites with the greatest amount of available soil moisture.

The most detrimental effect of damage on yield was the reduction of heads per plant and kernel weight. In most cases differences in the number of seeds per head between damaged and control plants were not evident.

Intertrap variability in catches of moths of the cutworms Leucania commoides Guenée and Peridroma saucia (Hübner) was tested by placing two traps for each species baited with artificial sex attractants at 1.6 km (1 mi) intervals to form a grid covering 64 km2 (25 mi2) near Domain, Manitoba. During the flight periods of the test species the attractants were 86.5 and 93.6% species-specific for L. commoides and P. saucia respectively. Moth catches varied between traps and flights, but the ranking of the traps by catch for each species was consistent during any given flight of L. commoides and during the first flight of P. saucia. The low intertrap variability in numbers captured of both species indicated the moths were uniformly distributed in the area. For L. commoides 10 traps within an area of 64 km2 would be required to give a population estimate within 20% of the true mean and for P. saucia three traps would be needed. The flights of L. commoides started abruptly each year and appeared to be triggered by rainfall. Flights of P. saucia did not occur below 10 °C but otherwise weather had no apparent influence on the flights. It was concluded that the moths of this species are blown in from the south each spring. Neither species showed a consistent distributional relationship with crops.

Trichadenotecnum alexanderae Sommerman is shown to represent one biparental (= euphrasic) species capable of facultative parthenogenesis (thelytoky) and three uniparental (= obligatorily parthenogenetic) sibling species, as determined by tests for mating, life history observations, and morphological analysis of specimens over the geographic range of the species complex. The name T. alexanderae is restricted to the biparental species because the holotype is a male. The three uniparental species are here named and described as T. castum n. sp., T. merum n. sp., and T. innuptum n. sp. The female of T. alexanderae is redescribed to allow its separation from the three uniparental species. A key to females of the species complex is supplied. All three uniparental species were derived from the biparental ancestor of T. alexanderae. Most collections of populations represented only by females consist of one or more uniparental species. Facultative parthenogenesis is shown to maintain a population of T. alexanderae through one generation only. The biparental species is found not to be restricted geographically to a relictual or peripheral range within the species complex, but to occupy a rather wide, north-temperate distribution across eastern North America.