Laboratory studies showed that eggs of Hylemya brassicae required 34 and 67 day-degrees at 10° and 30 °C. and 49 day-degrees at 15°, 20°, and 25 °C. to hatch when 7.2 °C. was used as the threshold temperature for development. Factors that were lethal to the eggs were temperatures above 41 °C. for one hour and periods of desiccation of 1, 1, 2, 5, and 9 days at 30°, 25°, 20°, 15°, and 10 °C., respectively.

First-instar larvae survived for approximately 2, 3, 5, and 8 days without food at temperatures of 20°, 15°, 10°, and 5 °C. Starvation for 24 hours immediately after hatching reduced initiation of feeding only slightly.

Crosses were made between adults of Neodiprion pratti (Dyar) derived from populations of spotted and striped larvae. Collections obtained over a period of years had indicated that these populations were homozygous for spotted and for striped larvae respectively; this conclusion was tested by spotted × spotted and by striped × striped crosses and was confirmed. The crosses spotted ♀, × striped ♂, striped ♀, × spotted ♂ and spotted F1 ♀, × striped ♂ were then made. The progeny from these crosses showed that the allele for sported is incompletely dominant over the allele for striped pattern. This incomplete dominance showed up in the occurrence of a few larvae of an intermediate type, and presumably accounts for the occurrence in nature of populations of larvae of intermediate types.

During four months of 1961 I had the opportunity of investigating and illustrating numerous species of Lepidoptera on the Island of Tutuila, American Samoa.

This was made possible through the cooperation of Mr. and Mrs. M. T. Hollingsworth of the Educational Division of the Samoan Government, the Director of Agriculture, Mr. Noel Bayless, and the Governor, Mr. H. Rex Lee.

Quarters and laboratory facilities were made available at the newly leased Agricultural Experiment Station of Mulinu'u, an 18-acre tract richly covered by native vegetation and cocoanut palms. The residence, formerly owned by the previous Governor, Peter Tali Coleman, was supplied with electricity, which made possible the use of neon and black light.

The tribe Ipini (sub-tribe Ipina) contains the genera Pityokteines Fuchs, Ips De Geer, Orthotomicus Ferrari (Balachowsky, 1949) and Orthotomides Wood. Some of the characters used in previous keys in this group are not constant within a genus but are useful when combined with other characters and when exceptions are specified. This article presents a key to the genera, with a discussion of some characters that have been used in previous keys. A new species is described and new synonymy and a new combination are established.

The life history and habits of Eucordylea ducharmei, a gelechiid needle-miner on spruce, are described along with short notes on some of its parasites.

External morphological differences between male and female adults of Sitophilus granarius (L.), useful for quick and accurate sexing, have been described and compared with differences described by other authors.

Mortality of immature Nasonia vitripennis (Walk.) was least on young house fly pupae (less than 48 hours old, at 24.5 ± 0.5 °C.) and increased with increasing host age. Increased mortality on old hosts was manifested principally as a decrease in female adult progeny, numbers of adult males and of mature diapause larvae remaining approximately constant. Reduction in the percentage of females in the adult progeny reared on old hosts probably resulted from superparasitism. This kills more female than male larvae and occurred more commonly on old hosts, each of which provides a smaller quantity of suitable food for the immature parasites. Adults reared on old hosts were smaller and relatively fewer of them were able to emerge. The proportion of the total mature parasite progeny that remained in diapause was greater on old hosts, probably because of qualitative differences in the food provided by hosts of different ages.

An ecological classification of dragonfly species into spring and summer types was proposed by Corbet (1954). Much of the basis for the classification rests with the pattern and period of adult emergence. Since little information of this type is known for North American species, the following observations are reported.

On May 20, 1962, I spent several hours collecting Baisaeschna janata and Didymops transversa along the New River, two miles north of McCoy, Virginia. A search was made at that time for odonate exuviae. None were found. I returned to the site at 9:30 a.m. the following day. The vegetation, tree trunks, rocks and detritus along the river were clustered with exuviae, all apparently of Gomphus vastus. Several thousand individuals must have emerged from that general area of the river. As an example of the density, 230 cast skins were counted along one 20-foot stretch of the river bank. Some individuals had transformed directly on the sand banks and others at a height of seven feet.

When onions were grown in cages under field conditions, the number of plants killed per egg deposited by hand showed no significant differences between any of the varieties studied, indicating that onion maggot (Hylemya antiqua (Meig.)) fed, developed, and survived as well on varieties Nebuka and Hishiko (Allium fistulosum L.) as on White Globe Southport (Allium cepa L.) and Beltsville Bunching (A. cepa × A. fistulosum), even though the last two varieties were more attractive for natural oviposition in the field. When larvae were fed in petri dishes with crushed tissues of onion plants, no significant differences were obtained between any of the varieties in the duration of larval stages, number of pupae, weight of pupae, or number of adults, whereas in glass vials, a better larval development, a higher number of heavier pupae, and a higher number of adults were obtained from the unattractive varieties. Therefore, it appears that the preference of the females to lay eggs in the field on varieties White Globe South-port and Beltsville Bunching is not associated with the nutritive value of the host-plants.

The searching behaviour of fifth-instar larch sawfly larvae on artificially defoliated tamarack branches and trees is discussed. Local defoliation is shown to be capable of causing appreciable mortality among early-instar larvae if feeding damage by earlier colonies forces them to wander in search of food. Air temperature affects the distance and rate of such larval movement. A considerable proportion of dislodged fifth-instar larvae are able to reach foliage and resume feeding on nearby host trees.

Hopping’s P. terminalis, which attacks the elongating terminal shoots of lodgepole pine in California, similarly attacks lodgepole pine in the Yukon and northern British Columbia. Cytologically it is unique, and on this basis, although phenotypically variable, it is demonstrated to occur on jack pine in Saskatchewan. Cytogenetic analysis proves it to be a hybrid species, thus accounting for both its internal cytological and external morphological polymorphism. Its fundamental taxonomic characteristics, determinable only in living specimens, comprise an unparalleled sexual dimorphism of chromosome complements and a restriction in breeding to current growth of lodgepole and jack pines.

After this article had been sent to press, we learned that G. R. Hopping (in "Lodgepole Pine in Alberta", Department of Forestry Bulletin 127, p. 84, 1962) had already discovered P. terminalis infesting lodgepole pine near Mercoal, Alta., in 1949.

Nymphs of Camnula pellucida hatching from an egg-bed originally about 800 square yards in extent had occupied, by the time they had reached the immature adult stage, approximately 160 acres. For the first three weeks the main factors affecting direction of advancing fronts appeared to be topographical features. The average rate of most rapid advance during this stage was only about 6 yards daily. Subsequently, dispersal appeared to become more random and general, proceeding at a maximum rate of about 20 yards daily, and rather rapidly over-running or outflanking most topographical features that had at first seemed to channelize movement. Dispersal in the nymphal stage was followed by characteristic reassembly of adults for breeding.

Rhodobium porosum (Sanderson), an aphid found on strawberry and rose, is discussed in this paper. The sexuales are redescribed and measurements given for the apterous and alate viviparous female.

In October, 1960, growers in the Robinsons-St. Davids area of Newfoundland reported that aldrin and heptachlor no longer protected rutabagas and cabbage adequately from attack by the cabbage maggot, Hylemya brassicae (Bouché).

In 1961, an experiment was conducted in the area, at Jeffreys, to determine if strains resistant to chlorinated hydrocarbons had developed. Six plots, each containing 58 cabbage plants, were set up on June 13 in an area heavily infested with the maggot in the previous years. The insecticides, rates of application, and results obtained are shown in Table I. All treatments were applied two days after transplanting and concentrated in the soil around the stems of the plants.