Haemolymph from Colorado potato beetles at larval, pupal, and adult stages was analyzed for pH, osmolality, and concentrations of magnesium, calcium, potassium, sodium, chloride, phosphate, and citrate. Differences in the concentrations of some ions observed between stages were used to formulate physiological saline solutions for the adult and larval stages.

This revision recognizes 13 species of Stilpon Loew in the Nearctic Region, including nine new species. A key is provided for the identification of adult specimens, all species are described, and their geographical distributions are mapped. Two informal species groups are recognized in the Nearctic Region, with the following included species: (1) S. graminum group — S. campestris Cumming sp.nov. (type-locality Assiniboia, Saskatchewan, Canada); (2) S. varipes group — S. chillcotti Cumming sp.nov. (type-locality 10 km E Evergreen, Alabama, USA), S. ctenistes Cumming sp.nov. (type-locality Salmon Creek, New York, USA), S. curvipes Melander, S. limitaris Cumming sp.nov. (type-locality Sapelo Island,Georgia,USA), S. pauciseta Melander, S. pilomus Cumming sp.nov. (type-locality Franconia, New Hampshire, USA), S. spinipes Melander, S. tribulosus Cumming sp.nov. (type-locality Gatlinburg, Tennessee, USA), S. tyconyx Cumming sp.nov. (type-locality Bedford, Massachusetts, USA), S. varipes Loew, S. vockerothi Cumming sp.nov. (type-locality Ottawa, Ontario, Canada), and S. wirthi Cumming sp.nov. (type-locality Dennisport, Massachusetts, USA). A world list of described species of Stilpon, including synonyms, is provided. Stilpon pectiniger Melander is a new junior synonym of S. varipes Loew and S. demnatensis Vaillant is indicated as a nomen nudum. Stilpon pleuriticus Melander, previously considered to belong within Stilpon, is excluded from the genus, and S. obscuripes Adams is transferred as Crossopalpus obscuripes (Adams) comb.nov. Lectotypes are designated for S. pauciseta Melander and S. pectiniger Melander. Homologies of previously confused structures of the male and female terminalia are summarized with reference to other Empidoidea. The monophyly of Stilpon is justified, including discussion of the phylogenetic relationships of the genus to the remainder of the Tachydromiinae. All described species of Stilpon, including extralimital species, are assigned to one of three proposed informal species groups (S. divergens, S. graminum, or S. varipes group), and zoogeographic patterns are discussed.

The larvae of eight Nearctic sawfly species in the genus Dolerus are described here for the first time. Six species, D. aprilis, D. tibialis conjugates, D. gilvipes albifrons, D. apricus, D. acidus, and D. subfasciatus, were reared from adults collected on the field horsetail, Equisetum arvense Linnaeus, and the larvae of two species, D. sericeus and D. nitens, were collected on grasses. The life history of Dolerus spp. is described. An illustrated key to the species dealt with is provided. Taxonomic affinities among. the species are briefly discussed.

Aspects of cold hardiness of Phytoseiulus persimilis Athias-Henriot and Amblyseius cucumeris (Oudemans) were compared. Mean supercooling points (SCPs) ranged from −19.4 to −27.1°C and increased during development from egg to adult. Feeding status, diapause, and low temperature acclimation had little or no effect on supercooling capacity. Temperature/mortality curves confirmed that both species, including A. cucumeris in diapause, are freezing intolerant in the sense that the SCP represents the absolute limit to low temperature survival. However, the mites survived exposure to −12.5°C for less than 90 min. The results suggest that the SCP is directly related to body mass in these mites and that their ability to supercool is primarily a physical characteristic rather than an adaptation for survival of exposure to subzero temperatures.

Fossil aphids found in 13 pieces of Cretaceous Canadian amber from Alberta, age 73 million years, are described, and their morphologies, systematic positions, and biologies discussed: Cretamyzus pikei Heie, gen.nov. and sp.nov., Mesozoicaphis electri Heie, gen.nov. and sp.nov., Mesozoicaphis tuberculata Heie, sp.nov., Mesozoicaphis canadensis Heie, sp.nov., Mesozoicaphisparva Heie, sp.nov., Calgariaphis unguifera Heie, gen.nov. and sp.nov., Albertaphis longirostris Heie, gen.nov. and sp.nov., and Campaniaphis albertae Heie, gen.nov. and sp.nov. Cretamyzus has been placed in a new family, Cretamyzidae, within the superfamily Aphidoidea, and the last four genera are placed in a new family, Mesozoicaphididae, within the superfamily Phylloxeroidea. It is contended that the origin and diversification of angiosperms occurred in the Cretaceous, resulting in extinction of several old specialized aphid groups feeding on gymnosperms while adaptive radiation of some less specialized and species-rich aphid groups occurred. The main part of the previously described Cretaceous aphids belongs to families that became extinct at the end of that period, and the fossils known from the beginning of the Tertiary already show a remarkably large resemblance to recent aphid fauna.

The egg laying regime of Forficula auricularia L., defined by different parameters (number of broods, proportion of females that produce two broods, number of eggs produced at each batch, and the proportion of the total number of eggs represented by the first batch), was studied in the laboratory and under seminatural conditions for a population from Montréal. Approximately half of the females produced two batches of eggs in the laboratory; however the number of eggs produced in the first batch was substantially higher than that of the second batch. In the field a single batch of eggs was produced. Comparison of our data with the literature showed that the Montréal population appears to have a greater resemblance to one of a cold temperate climate (Font-Romeu, Eastern Pyrénées) than one of a warmer climate (Rennes, Bretagne) for all parameters studied.

Three new species are described in the caddisfly family Uenoidae: Neothremma prolata, from Hood River County, Oregon; Neothremma mucronata from Lassen County, California; and Farula constricta from Multnomah County, Oregon. Following examination of the holotypes of several species, misinterpretation of the male genitalia morphology of Farula wigginsi Denning is corrected, leading to the recognition of that name as a junior synonym of F. petersoni Denning. Interpretation of male genitalic morphology in the original description of F. geyseri Denning is revised. Phylogenetic relationships are inferred from male genitalic morphology for the species of Neothremma and Farula. Biogeographic patterns of the species in both genera are highly congruent with the phylogenies.

Tuberculatus (Pacificallis) passalus sp.nov. and T. (P.) chrysolepidis sp.nov. are described and their relationship with other species of the subgenus Pacificallis is discussed. The status of T. (P.) quercifolii (Davidson) is elucidated. A key for the identification of the species of the subgenus is presented.

Field trials in northern Ontario in 1990 and 1991 confirmed that survival of spruce budworm larvae [Choristoneurafumiferana (Clemens)] (Lepidoptera: Tortricidae) parasitized by Apanteles fumiferanae Viereck (Hymenoptera: Braconidae) was greater than survival of nonparasitized budworm larvae following application of Bacillus thuringiensis var. kurstaki Berliner (Bt). Apparent parasitism by A. fumiferanae increased slightly when application of Bt was early (instar III or IV) but increased significantly when applications were later in the season (instars IV–VI). Delaying the timing of the spray conserved parasitoids while providing significant reductions in budworm densities and not compromising the primary objective of Bt application, i.e. the protection of current year foliage. The potential for long-term management of spruce budworm through the strategic integration of natural and imposed mortalities is discussed.

In the boreal forest of northwestern Ontario, where carpenter ants (Camponotus spp.) construct extensive underground tunnels, few worker ants were seen on the aerial portions of trees containing colonies of the ants or on neighboring trees, even though the trees were infested by large numbers of spruce budworm [Choristoneura fumiferana (Clem.)] larvae. Immunochemical techniques detected less spruce budworm soluble protein in worker ants from this area than in a laboratory colony that had been fed budworm larvae, or in a colony located in a spruce tree that was surrounded by gravel where the ants were unable to build underground tunnels and instead foraged extensively in the tree crown. This suggests that, in contrast to evidence from western North America, carpenter ants in the boreal forests of northwestern Ontario, and perhaps elsewhere throughout the range of the spruce budworm, are of limited importance as predators of the spruce budworm.

Single aerial applications of Bacillus thuringiensis Berliner (Bt) to control infestations of the eastern spruce budworm (Choristoneura fumiferana Clemens) have had varied operational success. Double applications are too expensive for general use, but might prove useful if directed to areas where the initial application was unsuccessful. This requires forecasts of the efficacy of the initial application in operational spray blocks within 4–5 days.

Data were collected in 30 spray blocks in 1989 in a feasibility study to determine if such forecasts of spray efficacy could be made from the prespray budworm population density, N0, and from the proportion of the population that had ingested a lethal dose Bt within 2 days of application, M. A mathematical model forecasting the postspray budworm population density, NF, was derived from population-dynamic considerations and fitted (r2 = 0.48, p < 0.0001):

The proportion of current foliage defoliated, D, depended (r = 0.81) on N0 and on whether the block was sprayed (I = 0) or not (I = 1):

Only one measure of defoliation involved M in any statistically significant way. The predicted (from values of N0) proportion of defoliation prevented by Bt application, dD, was weakly (r2 = 0.25, p = 0.002) related to M:

The large proportion of the variation in efficacy that remains unexplained by the models involving M limits the operational utility of this approach as it now stands for specific sites. The potential for further development of these models as decision support tools for fairly large spray blocks is discussed in terms of improving the sampling plan and including additional predictor variables.

Methods are also presented that reduce bias in calculations of population reduction (Abbott 1925) and foliage protection when data are available from few control and many treatment blocks.

A laboratory study of the fecundity, longevity, and intrinsic natural rate of increase of Epidinocarsis lopezi (De Santis) (Hymenoptera: Encyrtidae) was performed at 26 °C, the average temperature observed in the Congo during pullulation of its host Phenacoccus manihoti Mat.-Ferr. (Homoptera: Pseudococcidae). With 30 mealybugs per female per day, the parasitoid lives for an average of 41.4 days and lays 558.5 eggs. The net reproduction rate (R0) was calculated to be 269.9 females per female per generation, the average duration of a generation (T) was 33.9 days, and the intrinsic natural rate of increase of the parasitoid (rm) was 0.213. The fecundity observed in E. lopezi in this study was much higher than the figures previously reported. The rm of the parasitoid appeared to be higher than that determined by other authors for the mealybug. The limits of such a comparison are discussed.

The competition between Orius tristicoior (White) and Amblyseius cucumeris (Oude-mans), both preying on western flower thrips, Frankliniella occidentaiis (Pergande), was assessed. On single leaves in smail cages, mortality of A. cucumeris due to O. tristicoior was inversely proportional to thrips density; thrips mortality due to O. tristicoior was unaffected by A. cucumeris density. The proportion of A. cucumeris in the prey eaten was consistently less than its proportion in the prey initially available, both when thrips density varied and when A. cucumeris density varied. These relationships held for both immature and adult thrips. These results suggest that O. tristicoior and A. cucumeris could be used simultaneously for biological control of western flower thrips in greenhouse vegetable crops.

Widespread defoliation of sugar maple stands due to pear thrips, Taeniothrips inconsequens (Uzel), feeding occurred in Massachusetts in 1987 and 1988. To assess the role of tree health as a possible cause of these outbreaks, an experiment was conducted in sugar maple stands in Massachusetts in 1990. Sleeve cages were placed on mature sugar maples and stocked with adult female pear thrips to determine the relation between root starch reserves (an index of tree health) and thrips fecundity. The experiment was run at four sites, assessing both root starch levels and thrips fecundity on individual trees. Each stand showed a range from high to low starch values and trees at each end of the root starch index spectrum were selected for use in the experiment at each site. Analysis of data showed no differences between sites, apart from those linked to starch levels, and found thrips fecundity to be positively correlated with higher starch reserves. The results of this experiment do not support the original hypothesis that declining tree health was a causal factor in pear thrips outbreaks on sugar maple in Massachusetts.

Gross morphological changes in Ceratitis capitata (Wied.) during metamorphosis within the puparium are described and temporally correlated with the appearance of main differentiation markers. A table that allows determination of physiological age of pupal and pharate adult stages is presented.

During 1984 and 1985 macrolepidopterous larvae were collected by pole pruning of foliage of black birch, mixed oaks, black cherry, and red maple at Cooper’s Rock State Forest in northern West Virginia. A total of 3027 larvae representing 100 species in 14 families was collected. The most abundant species were the noctuids Polia latex (Gn.) and Morrisonia confusa (Hbn.), and the geometrids Probole amicaria (H.-S.), Itame pustularia (Gn.), and Melanolophia canadaria (Gn.). Of the 100 total species of larvae, 43 were recorded from birch, 61 from mixed oaks, 63 from black cherry, and 57 from red maple.

Survival and development of Ips paraconfusus Lanier larvae reared individually in intact Pinus ponderosa Laws. phloem without associated fungi and dietary supplements was demonstrated. Survival was reduced.in intact ponderosa pine phloem previously occupied by other larvae or by bluestaining fungi [i.e. Ophiostoma ips (Rumb.) vectored by I. paraconfusus, O. minus (Hedge.) H. & P. Syd. vectored by Dendroctonus brevicomis LeConte, O. clavigerum (Robins.-Jeff. & Davids.) vectored by D. ponderosae Hopkins, and Leptographium terebrantis Barras & Perry vectored by D. valens LeConte] compared with those reared without fungi or symbiotic yeasts. The highest proportion of larvae initiating tunnels and surviving to adult was observed for untreated eggs, and the lowest proportion occurred in the L. terebrantis treatment. Size was reduced and developmental rate was slower for larvae reared without fungi compared with larvae reared with associated fungi.

Tunnels excavated by first- and second-instar larvae reared without associated fungi were longer than those excavated by larvae reared with associated fungi. The most frequent larval turnabouts occurred with larvae reared axenically and reared with Ips yeast and O. ips. The fewest occurred with larvae reared with Ips egg niche plugs and from untreated eggs. Females reared free of any fungi or with Penicillium or Aspergillus did not oviposit in surface-sterilized ponderosa pine logs. Naturally eclosed females from ponderosa pine logs in which they developed, laid eggs in these sterilized logs. Potential for a new association among bark beetles and fungi is discussed.