A study of the anatomy and histology of the alimentary canal of Scolytus multistriatus Marsham suggests that the midgut diverticula are centres for the regeneration of the midgut cells and that the structure of the midgut epithelium and the proventriculus facilitate the rapid uptake of nutrients from food.

As part of a detailed study of the life system of the alfalfa weevil, Hypera postica (Gyll.), in southern Ontario, two methods were developed for estimating numbers of eggs in the spring growth of alfalfa. The first is based on direct counts of the eggs, which are laid in clusters and hence, aggregated in distribution; for moderate levels of infestation (ca. 8 eggs per bouquet), estimates with acceptable precision may be obtained by taking a single 3-stem bouquet of alfalfa from 80 randomly selected ft2 (.09 m2) quadrats within a field. The second is based on counts of the oviposition punctures which are randomly dispersed and consistent with the Poisson distribution. Although slightly less accurate, this method will provide a valid index of the number of eggs with less labour; acceptable precision may be obtained by taking a single bouquet from just 32 quadrats.

Numerical analyses have been carried out on some lepidopteran genera to find the effect of minimizing the number of characters used; the validity of drawing conclusions about the internal structure of a group which formed only a small portion of the analysis as a whole; the effect on numerical classifications when some characters are unknown for some taxa; and the diagnostic value of characters. The add-a-point program has been used to identify and to indicate the phenetic affinities of additional taxa.

The antifeeding compound AC 24055 (4′-(3,3-dimethyl-1-triazeno) acetanilide) was added to the diet of Drosophila melanogaster at several concentrations. Larval mortality and the duration of larval development increased significantly with increasing concentration from 125 to 625 parts per million (p.p.m.), and these effects were the same in males and females. Within this range of concentrations the weight of recently emerged adults declined with increasing concentration, the loss being greater for females than males. Egg production declined with increased concentration from 200 to 1000 p.p.m., particularly during the second week of egg production. Egg hatchability was not affected at 200 p.p.m., but from 400 to 1000 p.p.m. it declined rapidly from the second to the sixth day; with continued exposure, fertility was partly restored. The life span of adults decreased as the concentration increased from 500 to 1500 p.p.m. Concretions were observed in the Malpighian tubules of females reared in food containing 400 p.p.m. or more of the compound, but not in males.

Females of species in Cicindela have a groove or pit in the mesepisternum which is concluded to be a mating structure, "coupling sulcus," that is held by the mandibles of the male. Six character states of the coupling sulcus are described, and may be useful for identification at the species and species group levels. Primitive (groove) and advanced (cavity) states of the coupling sulcus are derived by comparison with a classification of North and South American Cicindela based on the male genitalia. I suggest the following hypothesis: the female mating structure evolved in response to the highly agile behaviour of diurnal tiger beetles; the advanced cavity-like coupling sulcus is a result of population adjustments to long periods of hot conditions; and the non-agile, crepuscular, and nocturnal habits of primitive tiger beetles such as Amblycheila, Omus, and Megacephala have resulted in no selection for a female mesepisternum coupling sulcus.

A variety of field sampling procedures were used to estimate population levels of the gypsy moth, Porthetria dispar (L.) (Lepidoptera: Lymantriidae), and the following natural enemies: Apanteles melanoscelus (Ratzeburg) (Hymenoptera: Braconidae), Blepharipa scutellata (Robineau-Desvoidy) (Diptera: Tachinidae), and Calosoma sycophanta (L.) (Coleoptera: Carabidae). Regression analyses indicated, among other things, that gypsy moth egg mass counts were not good indicators of tree defoliation, but that defoliation and number of gypsy moth larvae on branch terminals were correlated. Estimates of adult abundance of A. melanoscelus and B. scutellata were negatively correlated with estimates of numbers of immature parasitoids. Numbers of gypsy moth larvae parasitized by A. melanoscelus were positively correlated with numbers of A. melanoscelus cocoons sampled. Numbers of adult C. sycophanta were not correlated with larval numbers of this insect. It was concluded from these results that the procedures used to estimate numbers of natural enemy adults were not entirely adequate, but may be useful for supplementing other sampling methods.

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.

Each posterior spiracle is generally divided into three main parts—posterior spiracular plate, fell and spiracular chambers. The characteristic features of these parts and the moulting processes during the development of the larvae are described in the text. The main features in the development of the third instar larva are the replacement of the epidermal cells by chitin, shortening of the felt chamber and sear cord, increase in the depth of the spiracular chamber, gradual melanization of the posterior spiracle, and then its separation from the dorsal longitudinal trunk prior to pupation.

The synonymy, distribution, host range, and life history of the gregarious larval–pupal parasitoid Tachinaephagus zealandicus Ashmead, is discussed. Laboratory studies of its biology were conducted at 25° ± 2 °C using Musca domestica L. as host. Its developmental stages are described. Under laboratory conditions its life cycle lasted 23–27 days. Parasitoid development accelerated with higher average densities per host. Single standardized hosts produced 3–18 adult parasitoids. Mated females provided with hosts lived 50.4–67.2 h. The average length of the reproductive period and number of hosts parasitized were independent of host density; however, the average number of eggs deposited per host increased at lower host densities. Adult emergence displayed circadian rhythmicity independent of photoperiod over 3+ days.

In Neodiprion sertifer (Geoff.), mortality is greater in males than in females in the egg stage and probably also among early larvae, but in the late larval period females are more susceptible. The evidence consists of the difference in mortality between all-male and mixed (male + female) colonies, as well as the relationship of secondary sex ratio to preceding mortality and the number of survivors per colony. The effect of differential mortality on estimation of the primary sex ratio is discussed.

The punctigera group of the genus Euxoa is defined on the basis of genitalic characters. Species included in this group are Euxoa punctigera (Wlk.), E. spumata McD., E. stigmatalis (Sm.), E. aurantiaca n. sp., and E. cana n. sp. Adults and genitalia of the species are illustrated and a key to species is included.

A survey of the phytophagous arthropod fauna of the introduced legume crownvetch, Coronilla varia L., was conducted in Pennsylvania during 1971–73. Samples were taken from large forage fields, highway plantings used for erosion control, and greenhouses. Emphasis was placed on determining what known pests of other forage legumes are associated with crownvetch and on clarifying the relationship of the species to the host plant. Species were categorized as primary, secondary, and incidental according to their intimacy with the host. Biological notes, known host plant range, and association with other legumes are presented for 19 of the 33 primary species. The grasshoppersMelanoplus differentialis (Thomas) and M. femurrubrum (DeGeer) and the gelechiid moth Stomopteryx palpilineella Chambers caused defoliation in several highway plantings. Other abundant species were the alfalfa plant bug, Adelphocoris lineolatus (Goeze); potato leafhopper, Empoasca fabae (Harris); clover stem borer, Languria mozardi (Latreille); and nitidulid beetle Meligethes nigrescens Stephens. The similarity of the phytophagous fauna of crownvetch to that of alfalfa is discussed. Alfalfa pests found not to breed on crownvetch were the meadow spittlebug, pea aphid, alfalfa weevil, clover leaf weevil, clover root curculio, and alfalfa seed chalcid. As yet pest problems on crownvetch are few when compared with those of alfalfa and other forage legumes.

The larva of Chrysopa, in addition to feeding on aphids, takes a sugar meal from floral nectar, honeydew or, in captivity, solutions of sucrose. Sugar sources are located by a questing activity during which it scans the substrate with the antennae and palps. Feeding on honeydew may lead the larva towards aphids, on which it then proceeds to feed, and this is perhaps a normal sequence in nature.

It is pointed out that this duality of the feeding process — sugar meal and protein-rich meal — seems to be unique among endopterygote larvae, although well known in many adult insects. The larval sugar meal of Chrysopa may be a secondary characteristic which originated from the use of honeydew as an indicator when searching for prey.

Populations of leaf rollers on apple can be influenced by the proximity of alternative host plants, notably rose, privet, and antelope bush, in part because larval dispersal is common. Indications are that leaf roller population increases caused by parasite decreases are ultimate consequences of pesticide treatments, so that reductions in spray programs will not necessarily cause potential leaf roller pests to become actual pests. The composition of the leaf roller fauna on apple m the Okanagan Valley becomes increasingly complex as the environmental water balance is changed by cultivation and irrigation. There are indications that heavy vehicular traffic can be harmful to leaf rollers and their parasites nearby.

A procedure is described for evaluating commercial residual pesticides commonly used for house fly control. Blotting paper panels were treated with candidate products and aged up to 5 weeks. During aging, these panels were tested thrice at 1, 3, and 5 weeks after their treatment for efficacy based on mortality of female house flies exposed to them for 24 h in a cage. A product is reported satisfactory if the average percentage kill obtained is not less than 80, 60, and 50 at 1, 3, and 5 weeks aging respectively or within 5 percentage points less than these limits. A product meeting first and third week mortality limits is also considered acceptable.

Overwintering adults of the social wasp Polistes fuscatus (Fabricius) were collected in the early spring and placed in nest boxes under controlled conditions. Colonies were initiated, and one-, two-, and three-foundress associations were formed. Successful single-foundress colonies were similar to successful multiple-foundress colonies in developmental time for immatures, nest size, and total production of offspring. Multiple-foundress colonies were more likely to produce offspring than were single-foundress colonies. Half of the foundress wasps failed to reproduce, either because the colony failed or because they were non-reproductive subordinates. Apparently, wasps that were likely to fail at reproduction tended to join colonies rather than to initiate colonies. The relevance of this data to hypotheses on the selective advantage of foundress associations is discussed.

The signaria group of the genus Semiothisa is a complex of 10 extremely similar species, most of which are host-specific on certain genera of coniferous trees An eleventh species, S. sexmaculata, is also treated in this revision because of its close resemblance to members of the signaria complex, although its true affinity appears to be with the liturata–bisignata group. The species are described and illustrated, and their synonymy, distribution, variation and biology are discussed in detail, including an account of industrial melanism in a population of S. pinistrobata. Two new species names are proposed, and eight lectotypes designated. The main center of distribution is northeastern North America, and all of the known species except S. fuscaria occur on this continent. The one Holarctic species, S. signaria, which is generally the commonest in collections, also has the widest range of host plants, feeding on at least six genera of coniferous trees.

Application of a juvenile hormone analogue (ZR-777), prepared from an emulsifiable concentrate, to adults or to host foliage retarded the developmental and growth rates of the progeny. Possible means of transmission of the effect to the progeny are discussed.

A new species, Micropeplus minor, is described from Oregon. The species is placed in the Staphylinoides group and an existing key is modified to include the species.

A key to the subfamilies of Miridae based on fourth and fifth instar nymphs is provided and the value of some nymphal characters in arriving at relationships between the subfamilies is discussed. It is suggested that the reduction of parempodia to bristles most likely occurred twice in the family rather than that membranous parempodia were twice evolved. The Hyaliodes group is reviewed and the subfamily status accorded it by some authors is confirmed.