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Carabid beetles were collected using pitfall traps and tree bands in forest stands in southwestern Pennsylvania subjected to defoliation by gypsy moth for the first time. Some of the stands were treated aerially with Bacillus thuringiensis Berliner (B.t.). The guts of all carabids collected were tested for the presence of gypsy moth proteins using the ELISA technique. Twenty-seven of the 33 species (82%) collected from pitfall traps, and four of the seven species (57%) collected under tree bands, tested positive. Of the 1142 individuals from pitfall traps and 73 individuals from tree bands, the percentages positive were 45 and 38%, respectively. Calosoma frigidum Kirby had the highest percentage positive (78%) of any species. Statistically significant differences in percentages positive between B.t.-treated and untreated plots were found only for Pterostichus mutus Say and P. coracinus Newm., and when all species were combined. The presence of nucleopolyhedrosis virus in the gypsy moth population was unanticipated and may have influenced these results through increased feeding on carrion.

Western flower thrips, Frankliniella occidentalis (Pergande), originally distributed throughout western North America (Bryan and Smith 1956), have since spread to greenhouses in the eastern United States and Canada, and to many other parts of the world (Brodsgaard 1989). Populations have established outdoors in the southeastern United States (Chamberlin et al. 1992) and in several other warm regions of the world (Brodsgaard 1993). but have failed to establish in Ontario (Broadbent and Hunt 1991) and the northern parts of Europe (Brodsgaard 1993). We have not found reports of western flower thrips overwintering outdoors in the northeastern United States.

Pre-mating behavior of male gypsy moths was investigated in 0.2 ha circular plots containing from 0 to 72 virgin females/plot in untreated areas and in areas treated with an aerial application of 20 g/ha microencapsulated disparlure. Male moths in both treated and untreated plots oriented initially to trees, not directly to females. Mating was disrupted in treated plots but males continued search behavior. No anemotactic behavior was evident in either treated plots or untreated plots with females. In untreated plots, male moths were not caught on sticky panels (panels suspended at 2, 4, and 6 m) higher than pheromone baited traps set at 2 m. In treated plots, equal number of males were caught at all panel heights and in baited traps at 2 m. Previous mating and pheromone exposure histories of males did not affect the response of these males to traps baited with 4–5 mg of disparlure in untreated plots. In a test of the relative attractiveness of a cotton wick and a new laminated bait dispenser in Johnson traps, traps baited with the laminated dispenser had a greater male moth catch/male contact to trap than the traps baited with the cotton wick. Not all males contacting the Johnson trap were caught. A mode of action for disparlure as a disruptive agent in the long range sexual communication system of gypsy moth is proposed.

Four sampling methods for Ooencyrtus kuvanae (Howard) populations were compared for efficiency using coefficients of variation. On this basis, none of the sampling methods was uniformly superior to any other, but a cluster of 0.01 ha subplots was chosen as the best method because of the aggregation of both gypsy moth egg masses and parasitoids. From the estimated population variance per egg mass it was calculated that 150 egg masses should be sampled per plot to provide an error bound of 0.2 parasitoid per egg mass (α = 0.1). An analysis of variance indicated that variation among study areas was the largest source of variation, and that among day, within day, and plot configuration variation were significant. Estimates of parasitoid activity are most reliable during the period between 1300 and 1600 h EST. Activity of parasitoids was reduced on overcast days. In August, the distribution of O. kuvanae approximates that of the negative binomial but with too many individuals in the high frequency classes. In a compromise between cost and accuracy, the sampling scheme selected consists of thirty 0.01 ha subplots per plot sampled between 1300 and 1600 h EST on sunny days. This sampling scheme was found satisfactory using field evaluation.

Distributions of immature stages of the bronze birch borer, Agrilus anxius Gory (Coleoptera: Buprestidae), infesting young European white birch, Betula pendula Roth, were studied on a surface mine reforestation site in Pennsylvania. Eggs of A. anxius were common on boles of trees from mid-June through mid-August, in clusters of up to 14 eggs. Almost 70% of the eggs were in crevices in the dark triangular patch at branch origins. Larvae were present throughout the year. Fourth instars comprised 93.1% of the overwintering population.Vertical distributions of eggs, larvae, and pupae along the bole were random relative to available surface area. Consequently, each stage was more abundant on the lower half than on the upper half of trees. Eggs and first instars were concentrated on the northeast, or shaded, side of trees. Second and third instars were distributed randomly around the bole. Fourth instars overwintered and pupated primarily on the southwest aspect.

Male gypsy moths (Lymantria dispar (L.)) have a superposition compound eye. Electroretinogram (ERG) responses indicate low sensitivity in the ultraviolet region, higher sensitivity from 480 to 590 nm, and essentially no sensitivity in the red region. The microspectrophotometric absorption spectrum of the visual screening pigments shows low absorption in the ultraviolet and red regions and high absorption from 400 to 600 nm. Screening pigments migrate in response to illumination during diurnal activity periods, so the eye acts in the photopic mode. Because these pigments are essentially transparent to ultraviolet wavelengths, the eye may be in effect acting simultaneously in the scotopic mode for these wavelengths.

The spatial distribution of adultOoencyrtus kuvanae(Howard) (Hymenoptera: Encyrtidae) was examined in central Pennsylvania during 1978–1980. Data were gathered over a wide range of gypsy moth (Lymantria dispar(L.) (Lepidoptera: Lymantriidae)) densities and from all phases of population growth. There was a linear relationship between the log variance and log mean, fitting Taylor's Power Law with a power of 1.27. The degree of aggregation inO. kuvanaepopulations, as measured by the variance-to-mean ratio, was correlated positively with the abundance of the parasite, and was independent of host density. Aggregation was believed to result from the habit of the female parasite ovipositing repeatedly on the same egg mass, and the resultant progeny emerging synchronously. Behavior and density ofO. kuvanaepopulations were found to depend upon the gypsy moth population condition, i.e., low, rising, high stable, outbreak, or collapsed. The frequency distribution ofO. kuvanaepopulations fit the Poisson at densities less than 0.2 parasite adult per egg mass, a condition which occurred early and late (July, November) in the season, and the negative binomial above this density; a few distributions fit the log normal. The data were also analyzed using analyses of variance (multivariate and univariate), correlation, and regression techniques. All main effects, i.e., study area, host egg mass volume, egg mass height from the ground (within the 0–2 m sampling universe), aspect of the egg mass on the tree, and tree species, were important in explaining the variance in parasite abundance; study area differences were the most important. The effects of aspect and tree species were explained on the basis of small sample sizes, and not studied further. There was a positive correlation between host egg mass volume (= size) and parasite abundance. There was also a positive correlation between the height of the egg mass and parasite abundance during the summer; however, this relationship became negative by late fall. This seasonal change in vertical distribution was attributed to the tendency ofO. kuvanaeto be closer to the ground where they overwinter. Variation in adult abundance was generally greater among gypsy moth egg masses on different trees than among egg masses on the same tree, except at low parasite densities. This was attributed to the parasites searching for egg masses on one tree before dispersing to another.

The sexes of all but three of the North American species of Ips DeGeer can be separated reliably using characters on the frons, vertex of the head, protibiae, or declivital armature. In general, these secondary sexual characters are consistent within Hopping’s species groups.

Douglas-fir tussock moth cocoons were collected and their distribution recorded by crown level on white fir, Abies concolor, in northeastern California. Nine trees were sampled in two defoliation classes, light (20–30% defoliated) and moderate to heavy (50–80% defoliated). Cocoons were more abundant in the lower crown levels as defoliation became greater. The proportion of female cocoons increased toward the lower levels of the crown. An overall sex ratio of 1.2♂:1.0♀ was recorded. Significantly more male cocoons were parasitized than female. A list of the natural enemies of the tussock moth from the study area is given.

A total of 6995 summer generation Ips confusus (LeConte) adults was reared from logs of Pinus ponderosa Laws. under laboratory conditions. Emerging adults were collected every two hours throughout the day and their sex determined. Females predominated for the first eight days but the sex ratio at the end of 40 days was 1.18 ♀, ♀: 1 ♂. High differential loss of males before reproduction is discussed. From logs attacked in the spring 62.0% of the parent adults re-emerged. Large numbers of such parents capable of reproduction could greatly increase the severity of an infestation. Spring brood emergence totaled 67.64 beetles per sq. ft. of bark surface, while summer brood emergences from two different areas were 54.50 and 33.37 beetles per sq. ft. Above 72° F., peak male emergence occurs at the 10:00 a.m. or noon collection. Females exhibit a lesser peak in mid to late morning and a major peak in mid to late afternoon, but at temperatures below 72° F. a unimodal female emergence curve becomes apparent.

For the first time the male of Sirex juvencus californicus (Ashmead) (= Sirex obesus Bradley, new synonymy) is described; the female is redescribed. Biological notes on this subspecies are included, together with a key to the California species of the genus.

A lightweight, economical container used for long-distance shipment of adult Hymenopterous parasites of the Siricidae, and their hosts, is described. Survival of 94.8 per cent of insects in transit is reported.