A new genus, Pseudasiphonaphis, is described, with type species Asiphonaphis anogis Hottes and Frison, 1931. Two new species are described, Macrosiphum olmsteadi from Aster spp., and Macrosiphum (Sitobion) manitobensis from Cornus stolonifera Michx. Descriptions of previously undescribed fundatrix, ovipara and male of Masonaphis wahnaga (Hottes), and ovipara and male of Dactynotus richardsi Robinson are also given.

Existing theories and conclusions on the taxonomic relationships between various aphids are based on a study of those insects alone, and are often a matter of opinion.

True taxonomic relationships frequently are revealed when the host ranges of the insect parasites of aphids are considered.

Conclusions from a study of the host-relationships of aphid parasites of the family Aphidiidae (Hymenoptera: Ichneumonoidea): support the division of the superfamily Aphidoidea into Phylloxerina and Aphidina; support that Chaitophoridae, Callaphididae and Aphididae (including Lachnidae) form a monophyletic group, with the Aphididae the most recent member; support the view that the Rosaceae complex of Aphididae is natural; show that the aphid host plant usually has no decisive influence on the potential host range of an aphidiid species, even in cases of a taxonomically discontinuous change in host plants; and do not support the placement of the genus Drepanosiphum with the family Callaphididae, subfamily Phyllaphidinae.

Diaphnidia richardsi n. sp. is described. Orthotylus chlorionis (Say) and O. ulmi Knight are transferred to Diaphnocoris Kelton n. comb. Orthotylus translucens Tucker is a synonym of Diaphnocoris provancheri (Burque) n. syn. Diaphnidia capitata Van D. (= Diaphnocoris capitata, Kelton 1961) is transferred to Paraproba Distant n. comb. Species are keyed and male genitalia are illustrated.

The density and spatial relationship between the wasp parasite, Nasonia vitripennis, and the housefly host, Musca domestica, were investigated. As parasite dispersion decreased in a defined space, parasitism increased from 30 to 76% and host survival decreased from an average of 65.0 to 18.9%. The number of host pupae producing parasite progeny and the survival of host pupae decreased as the proportion of small host pupae increased. With host numbers increasing and parasite numbers constant, the mean number of eggs deposited per host increased significantly from 31.25 to 87.25 and the number of stings increased from 2.25 to 8.00. As parasite density increased and host number remained constant, the number of hosts which were nor attacked declined from a mean of 2.2 with 1 parasite to none with 32 parasites. Host survival declined from about 50% at the 1:8 ratio of female parasites to hosts to no survival at the 2:1 ratio.

Feeding tests in which various components were omitted individually from a chemically defined diet for adults of the parasitoid Exeristes comstockii (Cress.) (Hymenoptera: Ichneumonidae) showed that amino acids, salts, and vitamins were needed for maximal egg production and maximum numbers of eggs contained in ovaries. Omission of fatty acids, ribonucleic acid and cholesterol had no effect. Only omission of vitamins lowered egg hatch. Tests showed that the ovaries could recover from vitamin starvation.

Laboratory studies were conducted with the carrot rust fly, Psila rosae (Fabricius), to determine the effect of irradiation on reproduction. Irradiation of 15-day-old pupae with 1.4, 2.8 and 4.3 kiloroentgens did not adversely affect emergence. Treated females caged with normal males laid a few sterile eggs when the treatment was 1.4 kr. but none at the higher doses. Normal females caged with treated males laid a normal complement of eggs, and the per cent hatch was 10, 2 and 0 with treatments of 1.4, 2.8 and 4.3 kr., respectively. When flies of both sexes from pupae treated at 3.0 kr. were mixed with normal flies in a ratio of 6:1, the number of larvae were reduced by 93%.

Adults of Melanoplus bilituratus (Walker) were reared in the laboratory as groups of pairs, as groups in association with mature and immature males, as single pairs, and as groups of unmated females. Females of grouped pairs produced a larger number of eggs per pod and laid a greater total number of eggs that were more viable and hatched at least one day earlier than those of other groupings. Hatchlings of grouped pairs were more robust, 29% reaching the adult stage, whereas only 12% of nymphs from eggs of single pairs reached adulthood. Eleven per cent of the eggs of unmated females were viable, although only one hatchling lived to become an adult. Females of grouped pairs, of single pairs, and of those that were unmated reached their peak egg production in four, five and seven weeks respectively, after becoming adult. Young females matured three days earlier when mated with old males than when mated with males of their own age.

Three new species of Anomiopsyllus Baker, A. martini, A. durangoensis, and A. sinuatus, are described from the State of Durango, and a new subspecies, A. hiemalis mexicanus, from the State of Chihuahua, Mexico. Host-relationships and distribution of the Nearctic genera of Anomiopsyllinae are summarized, and a key to males of the twelve known species and subspecies of Anomiopsyllus is provided.

Nuclear-polyhedrosis virus, introduced into virus-free populations of the forest tent caterpillar, Malacosoma disstria (Hübner), in 1963, was carried over into the 1964 host generation and was spread into the surrounding areas from the points of introduction. The extent of spread in 1964 appeared to be influenced by the size of the area treated in 1963. In 1964 the epizootics developed slowly during the early instars and reached the highest levels late in the last instar. Many infected larvae crawled to the tops of the trees and died while eggs were being laid, thus, some egg masses were contaminated. This is one means by which virus may be spread from one generation to the next, but egg-transmission by adults appears to be the main method of spread over wide areas. Adults of the dipterous parasite, Sarcophaga aldrichi Park, may be important dispersal agents of disease in localized areas because they feed on virus-diseased larvae and are present from the time larvae enter the third instar until after adults have oviposited.

Survival of Agrilus liragus B. & B. is highly dependent on host condition. Any weakening factor such as defoliation, mechanical injury, or previous damage by A. liragus increases tree susceptibility to attack and enhances borer survival. The insect itself, through its local weakening effect on the phloem and cambial tissues, controls to some extent its own feeding environment. Although parasitism and predation do take place, the condition of the host tree is considered the prime factor determining the density of the borer population.

A new Nearctic species of Euderus Haliday is described and illustrated. Description is based on eight specimens reared from poplar twigs containing galls formed by Saperda moesta Leconte (Coleoptera) at Gore Bay, Ontario, seven specimens collected at Indian Head, Saskatchewan, and three specimens reared from poplar trunks at Kerrick, Minnesota.

On 12–13 July 1964, forest tent caterpillar, Malacosoma disstria Hübner, adults were carried southward from an outbreak in the forested area of central Alberta for at least 300 miles by the turbulent air associated with a cold front. Details of the area of dispersal and the weather system responsible are given.

In a test at St. John's from 20 August to 9 September 1964, grooved-board traps captured more specimens of the Eluropean earwig, Forficula auricularia L., than pitfall traps containing attractants. On 19 August two replicates of one grooved-board and eight Legner traps (Fig. 1) containing bran flakes plus an attractant were set up on a city lot. The Legner traps were set in the soil so that their tops were level with the surface. They were protected from rain by a 12 in. × 12 in. board held in position over the opening by short legs at the four corners. The attractants used were: peanut butter, cod oil, sugar, molasses, honey and macerated earwigs. The traps were attended from 21 August to 9 September and all earwigs removed daily and counted in the laboratory.

Adults of the European pine shoot moth emerge for the most part between dawn and 0900 hr. E.S.T. within a temperature range of approximately 11 to 25 °C. Adult emergence follows a field rhythm, emergence behaviour being initiated in pupae that have completed their development by the daily dark:light transition. Pupae held at constant temperature and under continuous light or darkness in the laboratory produced adults at any time of the day or night, whereas adults emerging from pupae held in an altered light cycle showed peak emergence following the dark:light transition. Observations of adult emergence in the field indicate that an average of 71 minutes was taken from the first appearance of the pupa in the exit hole until the wings of the newly emerged moth were expanded, dried, and returned to the normal resting position. Duration of the various phases of emergence behaviour are given, and discussed in relation to physical factors and predators. Following emergence, adults moved about the trees to more secluded and cooler sites once temperatures in exposed sites exceeded about 30 °C. During the hotter parts of the day, these movements commonly took the insects deep within the multiple tops of infested trees. As conditions moderated in the evening, and light intensities became conducive to flight, mating, and oviposition, the moths appeared in more exposed sites on the host trees.

Larval characterizations for the genera of North American Brachycentridae are revised and two new genera created, bringing to five the total number now recognized on this continent. Previous concepts of larval morphology in Micrasema are emended. Discovery of the larval stage of Brachycentrus (Amiocentrus) aspilus Ross necessitates elevation of this subgenus to generic status. Association of larvae with the two North American species placed in Oligoplectrum necessitates removal of one, O. dimicki (Milne), to Micrasema. Discovery of all stages of a new species on Mount Hood, Oregon, necessitates creation of a new genus. A provisional larval key to the genera of the North American Brachycentridae is proposed and the phylogenetic relationships of the genera are discussed. Validity of the Asian genus Oligoplectrodes is questioned.

Populations of the apple aphid, Aphis pomi De Geer, on apple were followed from 1959 to 1961, in Northern California. Population trends were generally upwards during early June and downwards through the remainder of the year. In 1959 a second population rise occurred during August. Populations were correlated with growth pattern of the host.

Also of importance in the characteristic decline of the apple aphid during July and August are the emigration of alate forms and predator activity. High temperatures were not thought to be an important mortality factor during the early summer months.

The genus Parapandemis is recorded from Canada, and P. borealis n. sp. is described from New Brunswick, Ontario, and Alberta.

The aqueous exudation from the sagittiform sensilla of Dermacentor andersoni Stiles larvae and nymphs, when placed in xylene and kerosene, indicates that the sensilla are more permeable than the rest of the cuticle to water. Potassium hydroxide also penetrates preferentially at these sites, reacting with haem pigments to form a pink colour in Dermacentor and Boophilus larvae. These observations, together with the complex structure of the sensilla, suggest that the sensilla are hygroreceptors.