Ovaries are one of the target organs hit by the nucleic acid antimetabolite 6-azauridine. All the malformations observed are caused by the suppression of mitotic activity, which appears to be the most sensitive to the applied drug. The inhibition of mitosis in the apical trophocytes results in depletion of the nutritive tissue in older females, followed by a disturbance of previtellogenesis and activation of oocytes. The blocked mitotic multiplication of prefollicular tissue results in exhaustion of this layer followed by a disturbance of regular egg chamber formation. The inadequate separation of oocytes by follicular cells causes the arrangement of the oocytes in paired chambers, often blocking the ovariole, or the formation of compound chambers. The oocytes sharing the compound chamber either remain separated by the ooplasmalemma or merge. Eggs with adherent dwarf oocytes or giant fused double eggs are oviposited. Endomitotic DNA replication and amitotic karyokinesis of the follicular cells are not interfered with by 6-azauridine, probably owing to the nucleic acid pools contained in the haemolymph. The lecytholitic cells resorb the ooplasm utilizing the nucleic acid-rich material.

Paracleruchus pieloui n. gen., n. sp. (Hymenoptera, Chalcidoidea: Mymaridae) reared from birch fungus, Polyporus betulinus (Bull.) Fr., is described and illustrated.

Seven aphid species, Longistigma chantali from Fagus grandifolia, Diphyllaphis microtrema from Quercus rubra, Hoplochaitophorus heterotrichus from Quercus prinus, Calaphis leonardi from Betula populifolia, Calaphis neobetulella from Betula nigra, Monellia hispida from Carya glabra, and Iziphya mackaueri from Carex sp., are described as new. Neosymydobius quercihabitus Miller and Calaphis betulaecolens (Fitch) are redescribed.

Four new species of the genus Lygocoris Reuter, subgenus Neolygus Knight, are described: knighti and walleyi from Ontario; piceicola, from New Brunswick and Quebec; and atricallus from Ontario and Quebec. Male genitalia are illustrated, host plants are listed, and relationships to other species are discussed.

Rows of hives were arranged in squares with their entrances facing outwards (N, S, E, W) within the temperate zone (at 49°38′ N., 97°09′ W.) and within the tropical zone (at 18°00′, 76°45′ W.). Bees tended to move southward along east and west facing rows in the temperate zone during July and August but not in the tropical zone during the time when the path of the sun passed through the zenith at midday (2 August 1969). Bees, in rows facing north or south, showed a greater tendency to move westward in the tropical than in the temperate zone. It is suggested that sun position may influence this movement of bees.

The adult densities of Hippodamia tredecimpunctata tibialis (Say), Coccinella novemnotata Hbst., and Coccinella transversoguttata richardsoni Brown, on corn fluctuated in July and August and reached their maxima at pollination, whereas the density of Coleomegilla maculata lengi Timberlake fluctuated much less. C. maculata, H. tredecimpunctata, and C. transversoguttata were more numerous on plants with a liver diet applied to their foliage than on untreated plants. H. tredecimpunctata, C. novemnotata, and C. transversoguttata were less numerous on plants that had their tassels removed and produced no pollen than on intact plants. C. maculata, H. tredecimpunctata, and C. transversoguttata were more numerous on plants exposed to the maximum amount of sunshine than on plants that were shaded for part of each day. H. tredecimpunctata was more numerous on plants situated at low elevation than at high elevation, whereas C. transversoguttata was more numerous at high than at low elevation. C. maculata and H. tredecimpunctata were more numerous on plants near the middle of a corn field than on plants at the perimeter of a field adjacent to buckwheat, whereas C. novemnotata and C. transversoguttata were most numerous on plants near the perimeter. Two-species associations of C. maculata and H. tredecimpunctata, C. novemnotata and H. tredecimpunctata, C. novemnotata and C. transversoguttata, and C. novemnotata and H. tredecimpunctata occurred on individual plants. Plant density and time of planting affected coccinellid density. Adult density was greatest at a plant density of 3.2 plants per square metre and adults were more numerous on early than on late planted corn.

Normal matings of Choristoneura fumiferana (Clem.) resulted in the transfer of single, persistent spermatophores. The mean duration of copulation was 4 hours with a range from 21/2 to 81/2 hours. All the first matings of males were fertile and the spermatophores were large, while an increasing proportion of the subsequent matings were infertile and the spermatophores became progressively smaller. Only fertilized females laid normal numbers of eggs. There was no evidence to show that insemination can be accomplished without the transfer of a spermatophore. However, the presence of a spermatophore in the bursa of the female was not always indicative of successful insemination.Males mated only once within a 24-hour period; they were least responsive to females just after emergence (< 0.5 day old) and most responsive when 2 to 4 days old. Females mated most readily when < 0.5 day old and became progressively less attractive or less receptive with age. Mated females were not as attractive as unmated females.

A new genus, Archepiolus, and a new species, schmidi, belonging to the family Neopseustidae and suborder Dacnonypha are described in this paper. This genus and species occupy a very primitive position in the Neopseustidae. The venation shows the most primitive features in all the Dacnonypha; also the male genitalia show a more primitive condition than that of Neopseustis meyricki Hering. Some aspects of the male genitalia are close to Mnesarchaea paracorma Meyrick of the Mnesarchaeidae.The discovery of this moth provides new morphological evidence on the problem of the ancestors of the Dacnonypha and of all Lepidoptera.

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.

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.

Thirteen species of black flies in two genera were found in the Crowsnest and Oldman rivers of southern Alberta. Of these, 11 were in the genus Simulium and 2 were in the genus Prosimulium. The two species of Prosimulium were found only in the Crowsnest River. Three species of Simulium were found only in the Oldman River, three only in the Crowsnest River, and 5 were found in both rivers.

The effects of temperature on survival during postdiapause development of the pre-imaginal stages of the larch sawfly, Pristiphora erichsonii (Hartig), were investigated in the laboratory using Manitoba material. Pronymph mortality increased progressively between 10° and 30 °C. Developmental arrest occurred in pronymphs exposed to 35 °C for periods up to 10 days prior to their transfer to 15 °C for completion of development. Pupae were more tolerant of high temperatures than were pronymphs.The results are discussed in relation to the possible physiological mechanism involved and the ecological implications for survival in the field.

Flights of green peach aphid alatae were recorded in suction traps and on trap plants from 16 May to 4 December. Four peaks of flight occurred in each of the years 1967–70, in early June, early July, late August and late September, the third being the largest. The aphid flew in very large numbers during August. There was a very significant correlation between the weekly catches from a suction trap and a group of Brussels sprouts trap plants at the same location and between two suction traps 3.2 km apart. By both methods the average weekly catch for 1967 > 1970 > 1969 > 1968.

It was observed that the parasite Dahlbominus fuscipennis Zett. was infected when developing in microsporidian-infected pupae of Neodiprion swainei Midd., Neodiprion lecontei Fitch, Neodiprion pratti banksianae Roh., and Pristiphora erichsonii Htg. The microsporidian was observed in the whole gut epithelium, fat body, and cerebral ganglial cells of the parasite. The parasitoid was infected only after the hosts had completed their winter diapause or at any time in non-diapausing species.

Dioryctria assamensis boring in shoots of Pinus khasya (labeled P. insularis) in Shillong, Assam, and Dioryctria raoi boring in shoots of Pinus roxburghii and Pinus sp. in north India are described as new species.

Psylla pyricola Foerster (pear psylla) transmitted Erwinia amylovora Winslow (fireblight) in 7 of 596 tests made from 1964 to 1969 at the University of Guelph, Guelph, Ont., Canada. Confirmation of transmission was by symptom expression and phage increase in Pyrus test tissue.

The history of Agria Robineau-Desvoidy (1830) and its relationship to Pseudosarcophaga Kramer (1908) are briefly reviewed. The original descriptions of Musca affinis Fallen 1817 (type of Pseudosarcophaga) and of the closely related Musca latifrons Fallén and Musca ruralis Fallén, are analyzed by comparison with each other and with authentic material, and the results of this analysis are applied to the original descriptions of Desvoidy’s species of Agria in an attempt to identify the type, Agria punctata R.-D., in the absence of a type specimen. It is concluded that Agria punctata has been identified correctly with Musca affinis and incorrectly with Musca latifrons.Agria affinis (Fall.) is replaced in the Nearctic Region by a sibling species, Agria housei n. sp., described herein. The relationship of Agria and related genera with the rest of the Sarcophaga complex is summarized with reference to the main literature sources.

Neoconocephalus crepitans (Scudder) and Microcentrum rhombifolium (Saussure) are recorded from Canada for the first time.