Ovarian development and egg production in the larch sawfly, Pristiphora erichsonii (Hartig), were studied in the development of a method for measuring reproductive capacity for population studies. Most of the oöcytes are mature at the time of adult emergence but some mature in the following few days. Quantitative differences in foliage consumption during the larval stages have an appreciable effect on egg production but normal environmental temperature differences and exposure to flooding during the spring development period influence ovarian development only to a limited extent.

Reproductive capacity can be determined by oöcyte counts of dissected adults of uniform age. The sample size necessary for estimates of various degrees of precision was calculated.

Several size measurements have a significant correlation with the numbers of oöcytes produced. The regression of numbers of oöcytes on adult weight is of limited usefulness in the estimation of reproductive capacity. This is largely due to the individual variability in the extent to which fat body tissue is utilized in ovarian development particularly in the case of the larger adults.

The factors influencing oviposition and feeding of Enoclerus lecontei, and the effect of temperature on egg development and survival, were studied in the laboratory.

When food was not a limiting factor, the total number of eggs laid, and the total number of bark beetles consumed by clerid pairs during their lives was strongly influenced by longevity of the female and to a lesser extent by female “vigor”. Female “vigor” and longevity were not necessarily coincident. The rate of oviposition and the rate of food consumption are mainly influenced by the “vigor” of the female clerid.

The effect of suboptimal food on oviposition was determined. Regression equations are given for estimating the number of eggs laid utilizing three measures of food supply, number of bark beetles supplied, their weight, and number eaten. The independent variables may be used separately or combined as a multiple regression.

Time for egg development varied from 5 days at 35 °C. to 28 days at 15 °C. Optimal conditions for development and survival were between 20° and 25 °C. Eggs can withstand cold storage (7° to 9 °C.) for 10 days before survival is impaired. Thereafter, mortality increases logarithmically until the 100 percentile is reached at about 43 days.

A key, bibliographies, and synonymies are given for the three species of Steremnius Schoen. S. scrobiculatus (Mann.) is considered a synonym of S. tuberosus Gyll.

During the past few years Mr. S. F. Condrashoff, Forest Research Laboratory, Canada Department of Forestry, Victoria, B.C., has been studying the insect pests of Sitka spruce on the Queen Charlotte Islands. One of these is a new species and the description of it is presented here to enable Mr. Condrashoff to describe the larva in a companion paper that follows (Can. Ent. 98: 703–706 (1966), in press).

A new genus Keltonia is described, with two new species from Florida, rubrofemorata and fuscipunctata. Psallus sulphureus Reuter (1907), formerly included in Reuteroscopus Kirkaldy (1905), is placed in this genus (n. comb.), and Psallus conspurcatus Blatchley (1928) is considered a synonym of sulphureus (n. syn.). Psallus balli Knight (1926) is transferred to Keltonia (n. comb.).

The black-headed budworm, Acleris variana (Fern.), is a forest pest native to North America. Periodic outbreaks have been recorded since the late 1920's in eastern Canada, where the preferred host is balsam fir. An outbreak generally causes 2 years of severe defoliation but no tree mortality and only a slight loss in radial increment.

Color patterns and measurements of the immature stages are given and limited data on age-interval survival rates are discussed. A key-factor analysis of 17 years’ data shows that population release is associated with years of low parasitism and favorable weather, while population decline is largely determined by late larval parasitism.

Evidence is provided that an obligatory pupal diapause is controlled by photoperiod. Diapause in H. cecropia is induced and maintained by a 12-hour photoperiod, and prevented or terminated by a 17-hour photoperiod; in either case, the incidence of diapause is graded according to the developmental stage at which the light regime is imposed. The validity of the distinction between "facultative" and "obligatory" diapause is discussed in the light of these results.

Pairs of Melanoplus sanguinipes and M. bivittatus were reared in cages and the eggs produced by each female were counted. M. sanguinipes laid an average of 328.7 eggs per female, 9.4 eggs per day, and an average of 21.8 eggs per pod. M. bivittatus laid an average of 354.9 eggs per female, 11.0 eggs per day, and 43.3 eggs per pod. M. sanguinipes produced a pod every 2.3 days and M. bivittatus one every 3.9 days. Feeding M. sanguinipes only every second day approximately doubled the longevity and oviposition period but halved the number of eggs per day.

The known distribution of Thymelicus lineola (Ochs.) now includes large areas in Ontario. Spot infestations are recorded from such widely separated areas as Lanoraie and Montreal, Quebec; Ottawa, Sault Ste. Marie, and Fort William, Ontario; and Terrace, British Columbia.

Infestations of T. lineola can be reduced by cutting infested areas during June, before adults emerge, or by spraying with Thuricide 90T at the rate of 2 pints per acre. The biology of the European parasite Stenichneumon scutellator Grav. is being studied prior to possible release.

Based on evidence from the structure of the male genitalia, the caddisfly genus Mystacides Berthold has evolved into four distinctive monophyletic clusters of species, the primitive longicornis group and the more specialized indica, azurea, and sepulchralis groups. When geographic range is plotted against phylogeny, the genus appears to have originated and proliferated chiefly in Eurasia, but with two fairly recent dispersals into North America. M. sandersoni (Malaya) and elongata (China) are described as new, and M. interjecta Banks is resurrected for previous records of American longicornis auct. nec. Linnaeus. M. longicornis (L.) is entirely palearctic. M. sibiricus Martynov is a new synonym of interjecta (Banks).

The pH changes occurring in different rearing media, both with and without housefly larvae (Musca domestica L.), were evaluated. In standard medium which consisted of non-fat milk, brewer's yeast, liver, agar, and water, the pH surrounding the eggs and first-stage larvae was about 5.6. As the larvae grew and agitated the medium, at 5 mm. depth the pH increased and by 72 hours read about 7.5. This 7.5 was significantly higher than the pH 5.0 recorded at the same depth and time in the standard medium without larvae.

Dermanyssus gallinoides is described as a new species of mite. It is parasitic on a sapsucker in British Columbia and has been collected from the nests of a red-shafted flicker and Lewis’ woodpecker in Colorado.

The weight and size of coccinellid adults varied with species, sex, and feeding. Intraspecies variation in weight was generally similar in the eight species studied. Females were more variable than males in body size. Females of some species were heavier and larger than males, and species can be classified on a basis of difference in the weight and size of the sexes.

An increase in the food supply after a period of food scarcity affected the sex ratio, as the minimum food requirement of females was greater than males. Females increased in weight more rapidly than males after feeding. The availability of food in the field affected the weight and size of some species. Adult water content was influenced by feeding but not by sex or the quantity of food given to the larva.

Males were more abundant in species with small sexual differences in weight and size. The degree of difference in weight and size between males and females may be used as a criterion to select species that are best adapted to survive when food is scarce.

Female Nasonia vitripennis (Walk.) parasitizing housefly (Musca domestica L.) pupae produce a smaller percentage of female progeny at high parasite:host ratios than at lower ones because they fertilize a smaller percentage of their eggs (in this species unfertilized eggs produce male progeny), and because more female than male larvae die on superparasitized hosts. The adult females fertilize relatively fewer eggs at high than at low parasite:host ratios for two reasons. First, they encounter relatively more previously attacked hosts, on which they lay a smaller percentage of fertilized eggs than on previously unattacked ones; second, they more often encounter other female parasites while ovipositing, and this interference reduces the percentage of fertilized eggs they lay.

Detailed studies on the population dynamics of the imported cabbageworm, Pieris rapae (L.), have been carried out at Merivale, Ontario, since 1959. A method for preparing life tables is described and a mean life table is presented for 18 generations of the species on cabbage. Population data for the preadult period show that there are three age intervals during which extensive mortality may occur: (1) between hatching and the second moult, (2) instars three to five, and (3) during the pupal stage. The analysis of successive age-interval survivals in relation to generation survival showed that the latter is largely determined by the survival rate for (2). Examination of the life tables revealed that a granulosis of the larvae caused by a capsule virus is the key factor in generation survival. Major mortality factors include rainfall and parasites.

The eggs, larvae, and pupae of Steremnius carinatus (Boh.) are described and characters given to distinguish them from those of Steremnius tuberosus Boh. A key separates the larvae and pupae of S. carinatus from those of S. tuberosus, species of Pissodes, and Scolytidae. The relationship of Steremnius to Pissodes and Hylobius is discussed briefly.

Two new species of Keltonia Knight are described. These are clinopodii from Florida and knighti from Mexico. There are now a total of six known species in the genus. A key is provided and male genitalia of five species are illustrated.

Larvae of the larch sawfly, Pristiphora erichsonii (Htg.), were collected in Alaska in 1965. This is the first record of this insect in Alaska. On 26 and 27 July 1965, stands of tamarack, Larix laricina (Du Roi) K. Koch, were examined at 16 locations along the Richardson Highway southeast of Fairbanks. Larch sawfly larvae were collected from 12 of the stands examined. Collection locations are shown in Fig. 1.