This is one of a series of papers on the development of life tables for the larch sawfly, Pristiphora erichsonii (Htg.), by a research team at Winnipeg. Previous papers have described techniques for obtaining population estimates for eggs, cocoons, and adults (Ives, 1955; Ives and Turnock, 1959; Turnock, 1960), and current work is concerned with the development of methods of segregating and evaluating the mortality factors affecting each stage. This paper describes the methods used to evaluate the amount of mortality caused by individual factors in the cocoon stage and discusses the problems of obtaining accurate and unbiased estimates.

The adult of Phyllocnistis populiella was described by Chambers in 1875. No detailed descriptions of the immature forms of this species have appeared in publication, although descriptions of other species in the genus have been published. Sich (1902), in his paper on P. suffusella Zell., presents a critical discussion of earlier works on the genus and gives a comprehensive account of the general features of the immature forms, although he omits details on setation and some other features of taxonomic interest. Certain aspects of larval and pupal morphology have been treated by Grandi (1932), Kozlovsky (1955) and Trägårdh (1913), while Hering (1951) and Needham (1928) have discussed structure as related to habit.

Prebble and Graham (1957) reported that initial flights of the ambrosia beetle, Trypodendron lineatum (Oliv.), occur from late March to early May depending on the time of rapid rise in maximum daily temperature. Flight and attack activity was investigated near Cowichan Lake, B.C., by Chapman and Kinghorn (1958). They concluded that the first heavy attack flights could be expected when the air temperature rose above 60°F. (15.6°C.) after most of the snow had melted. The amount of snow cover and altitude were found to affect time of flight.

The Douglas-fir cone midge (Contarinia oregonensis Foote) causes serious losses to Douglas-fir seed. In many areas it is considered the most damaging Douglas-fir seed insect (Johnson, 1958). Although its importance only recently has been recognized, its biology has alreadv been studied in both the United States (Johnson and Heilkkenen, 1958; Johnson and Winjum, 1960) and Canada (Hedlin, 1959, 1961). The overwintering habits of the larvae, however, have yet to be described. The purpose of this paper is to report upon their distribution in the forest litter over winter. The information provided may be of immediate practical use in developing cultural or chemical control and in sampling the larval population.

Head white; eye fuscons; labial palpus black, white at base beneath; antenna light wood brown, strongly bipectinate; body above white; abdomen with prominent black segmental bands above; bodv beneath white; legs white, with inner surface af front legs and distal parts of middle and hind tarsal segments infuscated. Fore wing above shining white, with narrow black contrasting markings; antemedial line nearly complete, the anterior element usualIy elongate and joining the remainder of the line, the rest of the line sigmoidal, acutely inflected on anal fold and near 3rd A; discocellular mark large and annular, complete or nearly so; postmedial line complete and of uniform width, excurved behind costa, then oblique to posterior margin; a narrow but distinct fuscous terminal line; fringe white. Hind wing above white; a postmedial row of more or less distinct black dots on veins in anterior part of wing; terminal line and fringe as on fore wing. Wings beneath white, markings of upper surface seen faintly by translucency; postmedial dots of hind wing well marked near costa; terminal line and fringe as above. Expanse 3 1-37 mm.

The apple maggot overwinters as a pupa within a puparium and develops to this stage in the fall five days after the larva enters the ground. It usually undergoes no visible morphological change until late the following spring or early summer (Dean, 1942). The adult emerges from late June to early September. Some pupae, however, remain dormant in the soil and the adults do not emerge until the second or third summer after pupation (Lathrop, 1955). Also, in some areas, a few adults emerge about two months after pupation (Phipps and Dirks, 193 3).

In Nova Scotia, a spray program that integrates chemical and natural control of apple pests has been evolved which is both economical and satisfactory. Among the natural enemies of injurious arthropods that have been favoured by this program are a number of general predators. Further investigation of the ecological principles on which integration is based requires a more intensive knowledge of the factors that influence the densities of these predators. Because of the difficulties of investigating these factors in the orchard, methods of simplifying the predator-prey systems have been sought (Lord, 1956, 1962). These attempts assessed the effects of low dosages of DDT on the interrelationships of phytophagous mites and their natural enemies.

Morgan and Anderson (1957) discussed in detail the synonymy of the Bryobia praetiosa Koch complex. They raised the apple inhabiting form to species status, and gave it the name, brown mite, Bryobia arborea.

The brown mite from apple trees in Nova Scotia was examined by C. V. G. Morgan, Summerland, British Columbia, and found to be morphologically similar to the B. arborea on apple in British Columbia. It is possible, however, that the Nova Scotian form may be a geographical race.

Investigations carried out over the past 50 years have made it abundantly clear that the chromosome, besides being a medium of evolutionary change, has an evolution of its own. In the animal kingdom, this has been elegantly proved by the extensive research on Drosophila (for a general review see Patterson and Stone, 1952), made possible largely by its possession of giant salivary gland chromosomes; by cytological analysis of hybrid rodents in the genus Gerbillus (Wahrman and Zahavi, 1958) and newts of the genus Triturus (White, 1946; Spurway and Callan, 1950; Callan and Spurway, 1951); by investigations carried out on various Orthoptera, facilitated by the clarity of meiosis in interracial (White, 1957a), interspecific (Klingstedt, 1939), and “intergeneric” (Helwig, 1955) hybrids; and by studies on the mantid genus Ameles (Wahrman and O'Brien, 1956), through the credibility derived from cytophotometric measurement of desoxyribose nucleic acid content. Much of the evidence adduced elsewhere, for example, Manna and Smith's (1959) survey of the bark weevil genus Pissodes, was based on comparative chromosome morphology, but, as will become evident later, our reasoning in this particular instance has so far proved correct.

Recently Dr. R. N. Sinha, of the Canadian Department of Agriculture, sent in for determination some spider mites causing serious damage to barley in Manitoba. Previously this same mite had been collected in North Dakota and Oregon. The mites proved to be an undescribed species of Tetranychus, a genus not usually associated with grasses.

The sampling of bark beetles and their natural enemies requires that bark be removed for examination of broods contained in the phloem. Counts of populations on bark samples are used to evaluate infestations for purposes of control and for studying population dynamics in the field. Bark samples have been cut from western conifers by chopping, sawing, or a combination of these operations. However, both these methods have disadvantages. Chopping produces ragged samples of varying size, and a saw tends to catch in the bark when cutting boundaries parallel to the trunk. Also, with either chopping or sawins, sample boundaries must be measured and marked as a guide during the cutting.

During the Tears 1959 and 1960 galls on rose bushes were collected in Westminster Township south of London, Ontario. Thc bushes grew along fencerows at the sides of roads surrounding the comniunity of Pond Mills. This community, is centred around tw ponds, North Pond (Fig. 1-A) and South Pond (B) which are joined by a narrow, shallow stretch of water. Nearby roads are Pond Mills Road leading south from London, Commissioners Road leading east from London and the road separating Concessions 1 and 1 of the Township of Westminster. The dates of collection of the galls and the location of the bushes from which they were taken are shown in Figure 1.

The spruce budworm, Choristoneura fumiferana (Clemens), is susceptible to a nuclear polyhedrosis virus and to a granulosis virus which may occur as single infections (Bergold 1950, 1951) or as double infections (Bird, 1959). Laboratory studies have shown that relatively heavy concentrations of either virus musr be injected or fed to hudworm larvae to cause infection and death. In one quantitative study Bergold (1951) estimated that the intralymphal LD50 of the polyhedrosis virus for the budworm is about 5000 times that for the silkworm, Bombyx mori L., when each is administered to its natural host. Field tests of the viruses were made in 1959 and 1960 to determine whether infection and mortality would result from spraying suspensions in infested forests.

The species described herein brings the number of described North American species of Rhopalosiphum Koch to thirteen. Only the apterous alienicolae of this species are known and these can be distinguished from the apterous alienicolae of other North American species by means of the key offered below.

While continuing work on a systematic revision of North American mites of the family Blattisocidae (= Aceosejidae), I have received from Mr. R. S. Soper, Jr., females of an undescribed species of mite with singular morphological attributes and an unusual association with an insect host. This species is given separate preliminary treatment in order to permit reference to it in ecological studies by Soper and Olson (in preparation).

Within the Lygaeid subfamily Rhyparochrominae, a number of species are placed in genera to which they do not belong. Changes in systematic position of a number of these have been published in the first number of this series. However, others cannot be placed in known genera and so new genera are necessary to contain these. Twelve new genera are here described to contain already described species.

Preliminary tests showed that, though Nasonia vitripennis (Walk.) can be propagated on housefly (Musca domestica (L.)) pupae at any stage of development, females parasitizing pupae less than 48 hours old, at 21.5°C., lived longer than those parasitizing older pupae. In view of the fact that the females always feed on the pupae after ovipositing on them, it seemed possible that the greater longevity of females parasitizing and feeding on young pupae had resulted from more suitable food provided by these pupae. As plans had heen made to investigate experimentally the host-finding capacity of this parasite species, it was essential that any effect of host age on this capacity, or on biological attributes of the parasite that influenced it, be standardized. Tests were therefore made to determine the effects, if any, of a host's age on the longevity and fecundity of female N. vitripennis laying and feeding on it.

In Neodiprion sawflies the cocoon stage, which extends from the completion of larval feeding until the appearance of the adult, is of considerable ecological interest. On the basis of voltinism and the seasonal occurrence of the cocoon stage, the genus as a whole may be divided into two distinct groups, which, however, do not correspond to the two major taxonomic categories of Ross (1955). On the one hand are species that overwinter only within the cocoon (e.g. swainei, lecontei, virginianus, excitans, and others); these may or may not have more than one generation per year. On the other hand are species that overwinter primarily in the egg stage (e.g. sertifer, pratti, abietis, taedae, and others); all of these are univoltine and may remain within the cocoon for an extended period in the summer, when conditions are still favourable for further generations. The European pine sawfly, Neodiprion sertifer (Geoff.), is typical in this respect. Despite its wide distribution in Eurasia and North America, and the variety of climates that it encounters, the length of the cocoon stage is so adjusted that adults do not emerge until late summer or early autumn, regardless of when larval feeding and cocoon spinning occurred.

Most laboratory studies of insect development have been conducted under constant temperature conditions. Since constant temperatures are rarely encountered under natural conditions, results of such studies are limited in their application. It is desirable to compare the effects of fluctuating temperatures and constant temperatures on insect development. For this purpose, control devices which produce regular alternations of periodic constant temperatures or continuously varying temperatures of a predictable nature are needed.

The larvae of Dioryctria abietella (D. & S.) are among the most destructive pests of the cones of slash pine, Pinus elliottii Engelm., and longleaf pine, Pinus palustris Mill., in the Southern United States. Larval instar data have been particularly useful in laboratory insecticide screening tests where it is essential to use larvae of the same age. The following is a brief account of a test to determine the number of larval instars of D. abietella in Florida.