Intra- and inter-crown distribution of eastern spruce gall adelgid, Adelges abietis (L.) (Homoptera: Adelgidae), on young white spruce, Picea glauca (Moench) Voss., was studied at three sites in New Brunswick, Canada. Within a branch, the majority of galls were found on lateral shoots. Similar distributions of galls within trees were observed regardless of whether 20 or 30 lateral shoots or all shoots on a branch were sampled. Gall densities were highest on mid-crown branches of open-grown trees 1–4 m tall and were not influenced by cardinal direction. After crown closure, most galls were found in the upper crown, above the point of branch overlap. In all circumstances, gall distributions were strongly clumped within trees. Inter-tree distribution of A. abietis galls differed significantly from a Poisson but not a negative binomial distribution, indicating a high degree of aggregation among trees. Therefore, a stratified random sampling plan using 20 lateral shoots of a mid-crown branch as a sampling unit would be adequate for monitoring A. abietis populations. If the mid-crown branches are undergoing crown closure, we suggest sampling in the lowest open-grown branch above the point of crown overlap.

The geographic range of the Douglas-fir twig beetle, Pityophthorus orarius Bright, was extended beyond the original provenance of southern British Columbia to northern California. A survey of 457 Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees in 1985 revealed that those with heavy cone crops were more likely to be infested by twig beetles than were those with a light crop. Furthermore, attack rates differed among clones. A second survey done in 1987 confirmed the importance of clone and cone crop in attack rate. In this survey, stressed trees were attacked at a higher rate than unstressed trees. Beetle distributions appeared clumped in both surveys, possibly because of semio-chemicals or oviposition behavior.

The leaf trichome densities of upper and lower surfaces of wild, Mediterranean Brassica spp. were determined using light and electron microscopic techniques. Two groups of plant species, one with a density of 2171–5312 trichomes per cm2 and the other with 0–30 trichomes per cm2, were tested in the laboratory for resistance against flea beetle feeding. The extent of feeding was determined in choice tests using leaf discs or detached whole leaves and in no-choice tests using clip-on cages on intact plants. Of the seven species tested, only two, B. villosa Biv. and B. villosa Biv. subsp. drepanensis which had a trichome density of > 2172 per cm2, were found to be highly resistant to flea beetle feeding. All other species had a trichome density of < 30 per cm2 and all suffered significant damage from flea beetle feeding. Behavioural observations indicated that a high density of trichomes on undamaged B. villosa leaves acted as a physical barrier to flea beetle feeding by preventing the flea beetles from firmly settling on the leaf surface to initiate feeding. Flea beetles readily initiated feeding on areas of B. villosa leaves where trichomes were inadvertently damaged suggesting that this plant did not contain significant concentrations of feeding deterrents. Electroantennogram (EAG) studies also indicated that B. villosa leaves are as stimulating to flea beetles as other Brassica species tested. Behavioural observations, feeding tests, and EAG studies indicated that trichomes, not other factors such as chemical repellents or feeding deterrents, are responsible for the resistance in B. villosa plants to flea beetle feeding.

Morphological, distributional, and habitat data are presented for North American species of the three genera of the subfamily Neomamersinae, Neomamersa Lundblad, 1953, Arizonacarus gen.nov., and Meramecia Cook, 1963. Neomamersa lundbladi lundbladi Cook, N. lundbladi paucipora Cook, and N. hexapora Cook are redescribed based on examination of types and newly collected specimens, and six new species of Neomamersa from the United States are described, namely N. boultoni sp.nov., N. psammicola sp.nov., N. californica sp.nov., N. chihuahua sp.nov., N. neomexicana sp.nov., and N. cramerae sp.nov. Arizonacarus chiricahuensis gen.nov., sp.nov. is described from the southwestern United States. Meramecia (Meramecia) anisitsipalpis (Cook), M. (Meramecia) perplexa (Cook), and M. (Meramecia) ocularis (Cook) are redescribed based on study of types and newly collected specimens, and M. (Meramecia) occidentalis sp.nov. is described from the western United States. Meramecia (Parameramecia) multipora subgen.nov., sp.nov. is also described from the southwestern United States. Revised diagnoses, keys, and distribution maps are presented for all North American taxa. Phylogenetic relationships of Neomamersinae are discussed, leading to the conclusion that comprehensive reassessment of the families Limnesiidae and Anisitsiellidae is warranted. Consideration of available phylogenetic and distributional data suggests that Neomamersinae originated in Gondwanaland before the separation of India from the rest of the southern supercontinent. Subsequently, the clade evolved and diversified extensively in South America. Neomamersinae apparently first entered North America either by crossing a "filter bridge" during late Cretaceous, Paleocene, or Miocene times or by traversing the corridor established with the formation of the Panamanian Isthmus during the late Pliocene. The group exhibits considerable taxonomic diversity in hyporheic and groundwater habitats in the United States, and the various species represent potentially useful indicators of water quality and the impact of environmental changes on freshwater communities.

Two new species of metallic-green Coleophora are described from the Nearctic region: C. alabama Landry from coastal Alabama, U.S.A.; and C. mexicana Landry from the state of Tamaulipas, Mexico. Modifications to the key to adults of the Nearctic species of metallic-green Coleophora from Landry and Wright (1993) are provided to account for these new species. Larval host plants and natural history are unknown. Both species are tentatively placed in the ramitella group. Coleophora mayrella (Hübner), originally from the Old World but long established in North America, is recorded for the first time from South America (Chile and Argentina).

The genus Parabrochymena Larivière is reviewed. Parahrochymna inbio and P. ruckesi are newly described. Parabrochymena barberi dituta (Ruckes) is given specific rank. Two synonymies are established: Brochymena aculeata Distant = P. haedula (Stål), Brochymena cuspidata Distant = P. haedula (Stål). A lectotype is designated for P. haedula (Stål). Species groups are characterized, and a key to all taxa is presented for the first time. As appropriate, for each species of Parabrochymena, the following are provided: citation of original description, synonymies, type material, description, geographical distribution, taxonomic comments, natural history, and illustrations of important structural characters. Choroiogical affinities are presented and systematic relationships are hypothesized. A biogeographic analysis of Parabrochymena and Brochymena Amyot and Audinet-Serville is also presented.

A study of different biometrie data of populations of Uroleucon (U.) picridis (F., 1775) sensu lato using canonical discriminant analysis resulted in the separation of two morphological groups. Exchange of host plants allowed us to conclude that the two groups correspond to two different species: Uroleucon (U.) picridis and Uroleucon (U.) mierae sp.nov. This latter species was described and a key to the identification of both species was given.

Temperature-dependent development of eggs, larvae, and pupae of the speckled green fruitworm, Orthosia hibisci Guenée, at constant temperatures of 5–30.0 °C, 7.5–27.5 °C, and 0.8–20.8 °C, respectively, was described. Development times decreased with increasing temperatures and minimum developmental times in eggs, larvae, and pupae occurred at ca. 27.5, 25, and 20.8 °C, respectively. Variation in development times of all life stages was modelled accurately (R2 values 0.98–0.99) with a Weibull distribution. Relationships between temperature and developmental rates of all life stages were described by linear degree-day (DD) and nonlinear poikilotherm models. There were significant differences (ANOVA, P < 0.05) among the slopes of regression equations describing developmental rates of different life stages and larval instars. Minimum developmental temperatures for eggs (3.4 °C), first- through fifth-instar larvae (4.7, 2.9, 3.6, 3.5, and 3.7 °C), and pupae (2.8 °C) were determined by extrapolation of linear regression equations to the x-intercept. Median development time of eggs, first- through fifth-instar larvae, and pupae required 99.0, 44.2, 51.5, 52.4, 57.1, 69.9, and 61.3 DD above the minimum developmental temperatures, respectively. Developmental rates of eggs and all larval instars averaged were described by six-parameter models exhibiting low- and high-temperature inhibition. Development of pupae was best described by a four-parameter model exhibiting low- but no high-temperature inhibition. This information should be useful for developing a phenology model to improve management actions against O. hibisci.