In peach orchards undisturbed by pesticides and where phytophagous mites were at endemic densities, spring populations of Typhlodromus caudiglans were small and remained so during early summer until phytophagous mites, especially Aculus cornutus, began to increase. T. caudiglans reached maximal densities in September. In such orchards T. caudiglans appears to be an important factor in maintaining Panonychus ulmi at low density levels. On trees where DDT applied the previous year had caused P. ulmi to build up and which could be repopulated by T. caudiglans from neighbouring trees, the predator increased very rapidly but appeared to reach an upper limit of density fixed by intrinsic factors, possibly cannibalism. Under these conditions T. caudiglans could not bring P. ulmi to endemic densities in one season, though it appeared to slow the mite’s rate of increase and to reduce its maximal seasonal density.

Wing base characters of taxonomic interest are listed. The morphology of these structures was described in Parts I and II of this series of papers (Sharplin 1963b, c). It is suggested that the presence of a tergopleural apodeme in the mesothorax is a definitive character for the Lepidoptera.

The midge, Phytophaga thujae Hedlin, is a common pest in cones of western red cedar, Thuja plicata Donn. In some years nearly 100% of cones in localities on Vancouver Island, British Columbia, are infested.

Adults emerge in March and April to oviposit on young cones. Eggs hatch during April and May. Larvae feed on seeds and scales, and in late summer spin cocoons in the cones, in which to overwinter. Prepupal and pupal development occur during winter.

Mortality factors include parasites and competition. Species of Torymus and Tetrastichus parasitize larvae of the midge. In years of severe infestation, competition in early stages can cause considerable mortality.

A portion of the population may remain in diapause in the larval stage each year.

Mining bees of the genus Evylaeus are remarkable in that their behaviour ranges from a strictly solitary to a complex social level. Knowledge of the many sexually dimorphic species is fragmentary, and the present paper describes one new species from northern Ontario and associates the sexes in two others. Biological notes and the illustration of male terminalia of closely related species are presented to facilitate their separation.

An abbreviated method for making balsam mounts is described. It uses the known rapid-clearing properties of phenolic solutions and eliminates the necessity of dehydration in various strengths of alcohol.

Euxoa piniae new species is described from material collected at Johnsville, Plumas County, California and compared with E. brunneigera latebra Benjamin, its closest relative.

Group IV of North American Ips (Hopping 1963a) contains I. avulsus (Eichhoff), I. bonanseai (Hopkins) and I. pini (Say), which breed mainly in pines. They have four spines on each side of the elytral declivity and the elytral interspaces are impunctate except I. bonanseai which occasionally has interspace punctures. A key to the species is given and Ips oregoni (Eichhoff) is made a synonym of Ips pini (Say). Group V has only one species, I. perroti Swaine, the only North American Ips with straight sutures on the antennal club. Data on hosts and distributions are given.

The seasonal history of the grape phylloxera, Phylloxera vitifoliae (Fitch), infesting vine roots in commercial vineyards in the Niagara Peninsula, Ontario, was investigated from 1960 to 1963, mostly on the variety Delaware. Galls caused by the phylloxera feeding on actively-growing feeder rootlets first appeared about mid-June, and increased to a maximum in late August or early September. Numbers of phylloxerae on the infested roots increased during the season until hibernation. Nymphs of the winged form of phylloxera were first found on the roots on dates ranging from 16 July to 22 August, and continued to occur for 11/2 to 21/2 months. Hibernation usually began in the latter part of September, and reached 90% between 2 and 23 October. Usually fewer than 10% of the hibernants survived the winter.

There were more infested vines, more galled roots, and relatively more phylloxerae in vineyards on clay loam soil than in sandy loam.

Hibernants resumed activity in the laboratory in a few days at room temperatures, and became adults in as little as 10 days.

Galls produced in 1961 yielded in that year G. gallaesolidaginis and the parasitic wasps Calliephialtes notandus, Eurytoma obtusiventris and Copidosoma gelechiae. Galls produced in 1961 and remaining empty but intact in 1962 were used in 1962 as shelters and egg-laying sites by spiders, lacewing flies, thrips, a beetle, a bee and an ant.

The information to be obtained from thorough life-history studies is an extremely useful tool, perhaps especially so when ecology is being emphasized, as it is to-day, by the life-table and other mathematical approaches to the study of population processes. This information is desired by workers in many fields of entomology – by the biological and chemical control experts, the biomathematicians, the theorists and even the taxonomists. However, much of the knowledge that these workers require, for instance the fine distinctions of behaviour and environment, has been overlooked in most life-history studies, and I strongly suspect that one of the weaknesses of studies of this nature has been the failure to analyse the mode of living of an insect (or, in the case of Lepidoptera, of the immature forms) in relation to the anatomy on one hand and environmental circumstances on the other. To look for these relationships, I believe that one requires (a) the ability and perseverance to perceive detail as minute as that required for a taxonomic study, and (b) a considerable knowledge of the taxonomic detail that is to be obtained from basic morphological studies. Therefore, in this paper, attention is drawn to pertinent structural characters of lepidopterous larvae and their probable connection with the behaviour and microhabitats of the larvae, in the hope that some guidance may be offered to future students of life-histories, at least in Lepidoptera.

Chrysopophthorus has a very wide distribution, occurring in four continents. C. chrysopimaginis Goidanich is placed as a new synonym of C. hungaricus (Z.-Kiss), which is transferred here from Helorimorpha (new combination). The other European species, C. elegans Tobias, is distinguished. Five new species are described; C. americanus from the United States, C. tropicalis, C. caribbeanus and C. brasileanus from South and Central America, and C. orientalis from Malaya.

A nuclear polyhedrosis virus was disseminated into field populations of an incipient outbreak of the forest tent caterpillar, Malacosoma disstria (Hübner). Mortality varied with the concentration of virus used and the age of larvae at the time of spraying. Larvae showed symptoms of infection more rapidly when sprayed with the higher concentrations and secondary infection and mortality occurred in areas where initial mortality developed during the early larval stages.

A new species of chalcid belonging to the genus Grotiusomyia Girault is described and illustrated.

Development time for the parasite Nasonia vitripennis (Walk.) was shorter on young pupae (less than 48 hours old at 24.5 ± 0.5 °C) than on older pupae of the house fly, Musca domestica L. This was primarily because of intrinsic differences between young and old house-fly pupae as hosts. Though less important, two other conditions in young hosts favoured a shorter mean development period for N. vitripennis: first, the smaller proportion of very small parasites, which mature more slowly than the larger ones; and, second, the greater number of parasite larvae per host, which is associated with more rapid development in this species.

A new species of Metapolophium is described, this being the first record of the genus from the Canadian arctic.

Observations by other authors showing that T. interruptor attacks more host larvae that had been previously parasitized by O. obscurator than unparasitized hosts were confirmed in the present study. Preference for buds previously visited by females of O. obscurator, as compared to unvisited buds, was demonstrated. Preliminary experiments to determine the factors involved in this preference and their implication are reported. These studies indicate that the policy of importing and releasing T. interruptor in North America to assist in the control of R. buoliana was unwise.

Light traps were operated in northern Minneapolis-St. Paul to determine effects of precipitation and control activities upon abundance of Aedes vexans. Data show that the number of female A. vexans taken at the traps is correlated fairly closely with total rainfall, in spite of intensive mosquito abatement operations within the area.