The Helophorus species recorded by McCorkle as H. brevipalpis Bedel, and by earlier workers as H. granularis (L.) is found, on examination of the types, to be H. orientalis Motschulsky, a species widespread in eastern Siberia.The types of H. orientalis are described, and a lectotype is designated. The type of H. sahlbergi Kuwert, a species synonymous with H. orienta’is, is also described. Further Siberian and North American material is described with reference to the type, and the means of distinguishing H. orientalis from H. granularis and H. brevipalpis are discussed.Fossil prothoraces from Pleistocene deposits at Brandon, Warwickshire and Great Billing, Northamptonshire, England, are referred to H. orientalis.The life histories of the three species are compared, and differences in the egg cocoons and larvae are illustrated. H. orientalis is shown by laboratory breeding to be parthenogenetic. In the other species no maleless populations are known, and although there is no proof that they cannot breed without males, this is considered very unlikely.The ecologies of the three species are discussed.

The anatomy and functions of the male and female reproductive organs of Allothrombium lerouxi Moss are described in detail. In the male, the reproductive organs consist of paired testes, paired vasa diferentia, a median seminal vesicle, a median ejaculatory duct, bursa expulsatoria, a penis, and a median accessory gland; in the female, they consist of paired ovaries, paired oviducts, a median uterus and a vagina. The function of the parts in the male differs from that reported in other species of Trombidiformes, and in females fertilization takes place in the spongy epithelium of the uterus instead of in the oviducts as in oribatids. Females also lack a receptaculum seminis and accessory glands.

The origins and insertions of the muscles of the gnathosoma, idiosoma, and appendages are illustrated and described. Idiosomal muscles are shown to be associated with external plates and in some cases with the endosternum. The articulations of all legs arc shown. The functions of most muscles are given. The principal muscles of the appendages as revealed in this study are flexor muscles but opposing muscles are shown to be much more common than previously thought. Hydrostatic pressure is apparently responsible for extension of the appendages. The position and function of the endosternum is given.

A colony of Leptocera caenosa (R.) was self-sustaining for 60 generations in a variety of organically rich media. With a wet larval medium of green grass meal and expanded mica in equal volumes at 17 °C the life cycle was completed (female to female) in an average of 31 days (egg stage, 2 days; larval and pupal periods, 13 days each). Green grass meal was superior to a standard cereal house-fly medium (CSMA) and legume leaf meals; a low coumarin strain of sweet clover was superior to a high coumarin strain. A non-sterile nutrient solution was also successfully used. In one sample of fresh alfalfa meal the pupal period was about 2.5 times longer than that in grass meal, possibly because of the presence of an estrogenic hormone.The species survived a 3-month exposure to 7 °C but not 1.5 °C, indicating that it could not readily survive out-of-doors during the winter in Saskatchewan.

Fifty-seven species of 27 families of mites associated with apple trees in Annapolis Valley, Nova Scotia, were recorded. Five species were phytophagous, 34 species were presumably predacious, and 18 species were presumably scavengers and fungus feeders.

Douglas-fir tussock moth cocoons were collected and their distribution recorded by crown level on white fir, Abies concolor, in northeastern California. Nine trees were sampled in two defoliation classes, light (20–30% defoliated) and moderate to heavy (50–80% defoliated). Cocoons were more abundant in the lower crown levels as defoliation became greater. The proportion of female cocoons increased toward the lower levels of the crown. An overall sex ratio of 1.2♂:1.0♀ was recorded. Significantly more male cocoons were parasitized than female. A list of the natural enemies of the tussock moth from the study area is given.

Newly emerged adults of several species of parasites of the balsam gall midge were collected in the spring and fall. Biological notes on individual species are given.

Evylaeus nigripes (Lep.) is a large, polylectic social halictine bee, common in the Mediterranean region. Haplometrotic and pleometrotic nests are established late in spring and clusters of from 6 to 15 cells are constructed and surrounded by a cavity. A summer brood of small females and a few males emerges from these cells in July. The summer females behave as workers; they remain in their mother’s nest, assist in the construction of a deeper and larger cell cluster, forage for pollen and nectar, but do not guard the nest. They show some ovarian inhibition in a matrifilial society but become egglayers in queenless nests or when establishing their own burrows. They are much shorter-lived than their mothers, require no diapause, and are unattractive to the summer males. The social level of E. nigripes is comparatively high; summer males are less than 5% of the total brood. Queen and workers are relatively distinct morphs, although caste determination can be influenced by environmental factors. Sphecodes alternatus Smith is its specific parasitoid whereas several bombyliids, mutillids, and conopids attack E. nigripes as part of a much wider range of hosts.

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.

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.

An investigation of the life-history and habits of Ips cembrae (Heer) has been made at the Ord wood, Cawdor Estate in Nairnshire. The species is polygamous and has a 1-year life cycle with two broods a year. The first broods result from eggs laid in May and June, producing teneral adults in August and September, and the second arise from egg-laying in late September and early October; these second broods generally overwinter under bark in the larval and pupal stages, and the adults emerge the following spring. There are three larval instars before pupation. Maturation feeding of the young beetles and regeneration feeding of the old ones take place either under the bark where broods have developed, or by attacking fresh host trees.

Evidence is presented to suggest that the gypsy moth, Porthetria dispar (L.), is numerically self-regulating through a shift in the quality of individuals induced by changes in nutrition. This qualitative change affects dispersal, behavior, developmental rate, and fecundity, and this provides P. dispar with the ability to respond to intrinsic and extrinsic factors faster and more efficiently than if dependent on selection. Adaptability is further facilitated because the change in quality can be induced either in the previous generation by the amount of nutrient reserves provided the eggs, or during the current generation by hunger, crowding, or cool temperature. This change is best characterized by an increase in the number of larvae with additional instars. In these larvae, a prolongation of instar I and a shift in behavior increases their potential for dispersal. The similarities and differences between P. dispar and Malacosoma pluviale (Dyar) are discussed.

An inexpensive, artificial diet made with carrot powder, a commercially available product of Saccharomyces fragilis, ascorbic acid, mold inhibitors, and agar gave as good or better yields of G. molesta (Busck) moths as was reared from apples. One moth per 1.25 ml of medium at a cost of.08c per moth was the best obtained.