Among the three species of potential hosts for Phoracantha semipunctata (F.) (Eucalyptus propinqua Deane and Maiden, Eucalyptus maculata Hook., and Angophora costata (Gaertner) Britten (all Myrtaceae)) tested in southeast Queensland, there were no differences in number of beetle galleries initiated by neonate larvae, larval mortality, larval survivorship, or parasitism rates. The larvae that survived to pupation in E. maculata produced significantly larger galleries, indicating larger larval size, than did larvae in either of the other two host species tested. There were no differences in the size of parasitized larvae among the three species of potential hosts. The results suggest that there were differences among species in host suitability for larval development but that females were either not able to distinguish those differences during oviposition or the selection for discrimination was not strong relative to the associated potential ecological costs.

Field studies were carried out on effect of attack by unmated spruce beetles, Dendroctonus obesus (Mann.) on log attractiveness. Test logs were screen-covered or sprayed with insecticide. Trays beneath logs, with glass-barrier traps beside them, were used to measure response of beetles from natural populations.

About 89% of the beetles attracted at six replicate sites were taken at logs containing introduced females. Males always predominated in responses to these logs. After the initial flight, about equal numbers of each sex responded to logs without introduced females. Response to the latter dropped to a low level after the initial flight, but beetles continued to respond well to logs attacked by females throughout the flight period. Use of increased attractiveness to logs following introduction of female beetles shows promise as a means of studying, directing, or controlling infestations of the spruce beetle.

The odor produced by male Ips grandicollis attacking caged loblolly pine bolts was not very effective in attracting marked beetles. Only 2.4% of the 9,417 beetles released around the attracting attacks were recaptured.Unscreened infested bolts lost their attractiveness to responding beetles when about 27 attacks per square foot of bark surface had been reached. More beetles attacked bolts placed outside of a beetle producing area than those within. The latter indicates that a dispersal flight may be needed before response takes place.

Seed produced by Fraser fir, Abies fraseri (Pursh) Poir., infested by the balsam woolly aphid, Adelges piceae (Ratzeburg), was compared with that originating from uninfested trees during a cyclic year of heavy seedfall (1969) in western North Carolina. Cones were significantly shorter and seed uniformly lighter and smaller from trees infested by the aphid. X-ray examination indicated the number of full seed from uninfested trees averaged nearly 70% and 42% higher than in comparable seed samples from infested trees. Germination tests indicated viability of seed from infested trees exceeded 32% and that from uninfested trees exceeded 75%. An important factor affecting survival of seed from the two sources appeared to be the relative susceptibility of seed to attack by Megastigmus specularis Walley. Almost 28% more seed were destroyed by these seed chalcids for aphid-infested trees than for uninfested trees.

For some time I have suspected that spruce needles were eaten out by Oribatoid mites. h recent lot of spruce litter from the Great Smoky Mountains (North Carolina-Tennessee) made possible this investigation with the following results.

Firm, undecomposed needles hold no mites. They are first acted upon by fungi which reduce the cell contents and a good deal of the mesophyll. In this condition the needles are soft and punky. It is only then that the mites are able to lay their eggs in the needles. Most punky needles examined sheltered an immature Phthiracarid mite (October 28th), sometimes two. These mites were found at one end of their excavation, having left behind them a completely dismanted needle and a litter of faeces. They leave the walls intact so that each of these soft, white mites is completely sheltered within its needle. The last molt is effected intra muros. Adults may thus be found within an undamaged needle. When hard and brown the adult cuts its way out and seeks a mate in the wide, moist world of the lower litter layer. The entire life of such a species is thereiore spent in the one horizon of the forest floor (the F2 layer). The leaf is left, a thin walled tube, its central stele and sclerenchymatous tissues completely eaten out and reduced to a thin litter of minute faeces (less than 0.1 mm. long).

Differences in the behavior of scale insects induced by their host plants has been observed, principally, in uniparental, bisexual, univoltine species. Behavior in endoparasites of such species also may be thus modified. The phenomena involved, reproductivity, sexuality, voltinism and, with the parasites, host-regulation, are related to the environmentally induced immunity of the host plant to its indigenous scale insects.This immunity, when not a regional phenomenon, is necessarily sporadic. When operative, it may he as complete as generic-immunity. Periodic host plant non-susceptibility is considered to he a physiological response to meteorological and edaphic conditions, a response usually rendering the plant temporarily unsuitable for coccid development. The interpolation of immune periods in the life of a coccid’s normal host plant necessarily disrupts the continuity of the host-regulative action of the coccid’s parasites. Host plant pheno-immunity was first clearly manifested in regions where Lecanium corni Bouché, L. tiliae (Linnaeus), and Saissetia oleae (Bernard) free of their regulative parasites, reproduced in great abundance. In regions to which these coccids are indigenous the limitation of their outbreaks to artificial monocultures attested to the obscure nature of host plant pheno-immunity. The cessation of host plant immunity to coccids, the subsequent heavy reinfestation, and then the parasitic elimination of the outbreak attested to the host-regulative power of parasitization.

This paper describes a new species of the genus Dasiops Rondani, which is known to be a primary pest of apricot fruits in California (Moffitt and Yaruss, 1961). In common with other Lonchaeidae, the adult of this species is small (about three mm. long) and rather stout; with a shining, metallic blue-black body; the female possesses a long, piercer-wpe ovipositor (Figs. 5-7) similar to that of otitids and trypetids. Other characters that serve to distinguish the family include: black halteres, hairy frons which is narrower in the male than in the female (Figs. 1, 2), a single, reclinate upper frontal bristle, diverging postvertical bristles, a row of bristles near posterior nargin of the mesopleuron, one or more sternopleural bristles and (usually) bare ptero- and hypopleuron. The genus Dasiops can be distinguished from other genera of Lonchaeidae by the presence of tiny, forwardly directed poststigmatal bristles which arise in the depression above the mesothoracic spiracle just cephalad of the anterodorsal corner of the mesopleuron.

In most species of Euxoa a high proportion of the females mate more than once. The mean number of matings per mated female in natural populations of 13 species ranged from 1.65 to 10.86. Mating frequency data for laboratory populations of three of these species indicate that laboratory rearing and confinement does not significantly alter the incidence and level of multiple mating. The propensity for multiple mating is species characteristic although the observed level in samples from the field can vary significantly depending on the age structure of the populations sampled and probably also on other parameters of populations or environmental factors. Since species differences in the tendency for multiple mating are probably manifestations of different reproductive strategies some of the possible advantages of this behavior are discussed.

Adult potato aphids, Macrosiphum euphorbiae (Thomas), caged on potato terminal leaflets treated systemically with imidacloprid solutions ranging between 5.4 × 10−4 and 5.4 × 10−8 mL per mL water showed a significant reduction in the distance they travelled, time taken to travel a given distance, and flight propensity but no significant differences in the frequency or duration of short probing behaviour. The frequency of adult apterous potato aphids colonizing untreated potato leaflets or leaflets treated with an imidacloprid solution (5.4 × 10−4 mL per mL water) was not significantly different, indicating no repellency. Potato aphids moving from systemically treated to untreated leaflets did not recover much and their reduced walking ability was maintained for days. A 3-day exposure to vapour from an imidacloprid solution (5.4 × 10−4 mL per mL water) did not produce significant mortality or changes in nymphal production. The daily cumulative mortality obtained by caging potato aphids on potato leaflets placed in an imidacloprid solution (5.4 × 10−7 mL per mL water) was similar to that obtained in the field, on 20-day-old plants treated at planting with imidacloprid applied at 0.02 g Ai/m. None of the rates of imidacloprid tested stimulated the dispersal of apterous or alate potato aphids.

In the summer of 1969, one year following a spray program to control spruce budworm with Phosphamidon and Sumithion in northwestern Ontario, five species of carabids and two species of lycosids were studied to assess the long term effects of insecticide spray on forest floor arthropods. For 15 weeks in the summer of 1969, beetles and spiders were almost always more numerous in the control area than in the sprayed area. Populations of the spiders and beetles are briefly discussed.

Modified versions of the standard Reed-Rich citrus thrips trap were compared for trapping efficiency and labor required. The number of migrant Scirtothrips citri (Moulton) captured per unit trapping area of a PVC-acetate trap was comparable to the number captured per unit area of the Reed-Rich trap, though the PVC-acetate trapping surface was about 35% that of the 929 cm2 standard trap. The reduced counting surface and the use of disposable acetate sheets reduced to one-quarter the time required for field-laboratory handling, preparing, and processing. The PVC-acetate trap is recommended as a new standard trap for monitoring S. citri population levels in California and Arizona citriculture.

Group VIII of North American Ips contains I. interruptus (Mannerheim), I. engelmanni Swaine, I. amiskwiensis G. Hopping, I. sulcifrons Wood, I. pilifrons Swaine, I. yohoensis Swaine, I. tridens (Mannerheim) and I. semirostris G. Hopping. Females of some species have dense brushes of long setae or pads of short pile covering the frontal protuberance. Species are described and a key is given. All of them breed in spruce, six in the boreal forest and two farther south in the Rocky Mountains.

Wasps of the genus Polistes have a number of characteristics that make them particularly suitable for studies on insect social behaviour. The females construct nests with exposed combs, have a reasonably complex social behaviour, and usually lack obvious morphological caste differences. In addition, the adults of many species establish colonies as groups of siblings (foundress associations), a method which is intermediate between colony founding by swarming, and colony founding by individual queens (Wilson 1971). Because of these characteristics, Polistes have been of interest to biologists who are concerned with the evolution of social behaviour in insects (e.g. Alexander 1974, Gibo 1974, Lin and Michener 1972, West 1967, West Eberhard 1969, 1975). Consequently, there is a need for a simple technique for rearing various species of Polistes under controlled conditions. Gibo (1974) briefly described modifications of Gillaspy's (1971) rearing method for P. apachus which made mass rearing of P. fascatus possible. This note describes the modified method in greater detail, and includes improvements that have resulted in increased yield and greater synchrony of colony growth. The improvements have been developed over 3 years and the method has been used to rear more than 100 colonies of various species of Polistes, including P. fuscatus, P. apachus, and P. dorsalis.

The seasonal development of N. swainei was recorded in northwestern Quebec for six consecutive years from 1956 to 1961. Larvae normally spun cocoons during September when temperatures were usually below the optimum for survival. An earlier and more favourable spinning period depended principally upon an early adult emergence which, in turn, was governed by prevailing temperatures, the degree of shading of the humus, the presence of encapsulated tachinid parasites, the prior period spent in prolonged diapause, and the geographic origin of the specimens. It was concluded that early emergence of adults followed by rapid development of the immature stages for successive years are prerequisites for epidemics of N. swainei in northwestern Quebec, and are unlikely in very dense jackpine stands.

The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Scolytidae), is a common bark beetle species found throughout much of North America. In California, D. valens and the California fivespined ips, Ips paraconfusus Lanier (Coleoptera: Scolytidae), are sympatric and often colonize the same tree. In an unrelated study, we observed that I. paraconfusus attack densities in logging debris were inversely related to D. valens attacks on freshly cut stumps. In this study, we test the hypothesis that allomonal inhibition occurs between these two species. Components of the aggregation pheromone of I. paraconfusus (racemic ipsenol, (+)-ipsdienol, and (–)-cis-verbenol) inhibited the response of D. valens to attractant-baited traps. Substitution of racemic ipsdienol for (+)-ipsdienol did not alter this effect. Doubling the release rate did not enhance inhibition. Racemic ipsdienol was not attractive to I. paraconfusus. Temnochila chlorodia (Mannerheim, 1843) (Coleoptera: Trogositidae), a common bark beetle predator, was attracted to the I. paraconfusus aggregation pheromone. These results could have important implications for the development of an effective semiochemical-based management tool for D. valens.

Female wheat midges, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), were provided with wheat spikes, Triticum aestivum L. (Poaceae), for oviposition while being exposed to air that had passed over wheat spikes of contrasting genotype or growth stage. Spikes of postanthesis ‘Roblin’ and preanthesis ‘Key 10’ are known to deter oviposition. Volatiles emitted by these spikes suppressed oviposition on preanthesis ‘Roblin', which is preferred for oviposition. Volatiles emitted by spikes of preanthesis ‘Roblin’ did not increase oviposition on preanthesis ‘Key 10'. Reduced oviposition on a resistant genotype and on a deterrent growth stage of wheat is consistent with production of deterrent volatiles rather than a lack of stimulatory volatiles.

Nymphs of the leafhopper Aphrodes bicincta (Schrank) first appeared in the field at the end of May or early June. Emergence of nymphs was protracted over a long period with second and third instar nymphs still being found when adult males were already present. Early instar nymphs were found on strawberry, Trifolium pratense L., T. hybridum L., Plantago major L., Taraxacum officinale Weber, Capsella bursa-pastoris (L.) Medic., Erigeron canadensis L., and a species of Brassica. There was only one generation per year, the winter being spent in the egg stage. Eggs deposited in plants in the field hatched when brought into the greenhouse during the winter months.In greenhouse studies, eggs were most often found oviposited on the surface of the soil or completely embedded in the petioles of leaves and in clumps of peat moss. Although eggs held at room temperature (70°–75°F) occasionally hatched, cold treatment (45°–50°F) of several weeks resulted in eggs hatching in as short a time as 14 days following their return to room temperature. There were five instars in the nymphal stage. The first four were relatively uniform in length but the fifth was at least 3 days longer than any other instar. Male insects completed the nymphal stage in 38.4 days and female insects in 41.3 days. Descriptions and measurements of the five nymphal instars and male and female adult insects are given. Adult male insects survived well for about 4 weeks and then declined rapidly. Female survival remained relatively high for at least 8 weeks. Some females have lived for up to 20 weeks. Fecundity varied with one female producing 51 offspring and others producing 1.

Preliminary study of the outbreak of the European spruce sawfly (Diprion polytomum Htg.) in the Gaspe Peninsula, undertaken in 1931 by the Division of Forest Insects, showed that the extent of the infestation was such that the sawfly could not be economically controlled by chemical or mechanical means. It was found, also, that the sawfly was not attacked by parasites.

New hosts of an introduced Oriental ambrosia beetle were tupelo (Nyssa aquatica), swamp cypress (Taxodium distichum), and black cherry (Prunus serotina). Known distribution was extended southward into North Carolina. A partial seasonal development with simple through complex gallery systems was observed.

In the irrigated districts of southern Alberta larvae of Culiseta inornota (Williston) were found to be infected with the fungus Coelomomyces psorophorae Couch, identified by J. N. Couch, Department of Botany, University of North Carolina. This is the first record on C. inornata in Canada.

The resting sporangia (Fig. 1) were found in the thoracic and abdominal cavities of the larvae. The infected larvae were darker brown in color, larger in size, and slower in movement than the non-infected ones.