A series of 15 embryonic stages of Periplaneta americana Linnaeus is defined on the basis of external morphological characters. These stages permit the study of internal development of embryos whose chronological age is unknown or from embryos incubated at different or varying temperatures. The stages, while extremely useful, are entirely arbitrary divisions of a continuous developmental process and a larger or smaller number of them could have been designated.

The cervical and thoracic musculature of the first-stage nymph is described for the first time, and its genesis is followed in the embryo. The embryonic and nymphal muscles are compared with those that have been reported for the adult.

The specific status of Neodiprion nigroscutum Middleton is firmly established by new data. The adult female is mostly black and brown. The second annulus of the lancet is generally weakly developed ventrally. The larvae have black head capsules in the first instar, but this coloration usually changes to reddish brown in the later instars. The third, fourth, and fifth feeding-instar larvae have unbroken subdorsal and supraspiracular lines, and broken postepipleural lines, but lack an epiproctal spot. The nonfeeding-instar larvae often have a pink body color. The egg mass of most females is green. Jack pine is the preferred host. The fecundity is approximately 100 eggs, but they are typically distributed over many branches, usually in one needle on each branch. Larval colonies composed of first- through fourth-instar larvae usually contain 3–10 larvae, while colonies of fifth-instar larvae usually contain 1–6 larvae. There are two generations per year in southern Wisconsin. Feeding-instar larvae are present in late May and June, and again (second generation) in August and September. The species is distributed throughout the jack pine stands of Wisconsin. Phenological data and notes on parasites are presented.

Philodromus spp., especially praelustris Keyserlmg, and sometimes Theridion murarium were the only abundant spiders in peach orchards, though small numbers of many other species were present. No satisfactory method of sampling the population density of all species was discovered. The spider population as a whole reached a minor peak in June and a much higher peak in early August. A single tree may contain more than 200 spiders. When fed only on Panonychus ulmi (Koch), young P. praelustris eventually died without moulting; young of T. murarium moulted once or twice but their development was slower than that of those in the orchards. Chironomids were the commonest prey of P. praelustris and apparently of other spiders in the orchards.

Spiders collected from peach plots with different densities of P. ulmi and Bryobia arborea Morgan and Anderson were examined for pigments of these mites by paper chromatography. Some spiders in all collections had fed on the mites, and the percentage that had done so usually varied directly with mite density in the plots. Spiders form part of the complex of minor predators that aid the major predators in regulating the density of P. ulmi at endemic levels.

Many of the small leafhoppers that feed and reproduce upon the foliage of birch trees belong to the subfamily Typhlocybinae. The main species are Typhlocyba hockingensis Knull, T. pomaria McAtee, Ribautiana foliosa (Knull), Edwardsiana bergmani (Tullgren), Empoa latifasciata Christian, Dikrella cruentata (Gillette), Alebra albostriella (Fallen) and several Erythroneura species. Their ecological requirements and life histories are described. Notes on morphology and illustrations of each species except the Erythroneura are included.

Douglas-fir beetle, Dendroctonus pseudotsugae Hopk., broods developed more rapidly at a constant 21 °C. than at 13 °C. or at the temperature outdoors during the summer. The dry weight and fat content of young larvae developed at 13 °C. were lowest, whereas the dry weight and fat content of adults reared at 13 °C. were highest. Adults reared outdoors had the lowest dry weight and fat content. The differences in weight and accumulated fat are attributed to the effect of temperature on the length of time available for feeding, and on the rate of metabolism in the various developmental stages. Variations in temperature during the prediapause–diapause period also produce changes in the relation between the size and fat content of the adults.

Alternation of generations, or heterogony, wherein progeny resemble their grandparents but not their parents, is a little-known aspect of some cynipid life histories. This study represents the first record of its occurrence within the genus Besbicus, until now recognized solely from agamic females. The bisexual generation described herein has not been described previously. The literature on B. mirabilis (Kinsey) is reviewed briefly and some of the difficulties of cynipid study are assessed. The life history and ecology of both generations is presented and the immediate insect associates are discussed.

The effects from treating populations of predacious mites with a number of spray chemicals are tabulated. The species include Phytoseiidae: Typhlodromus pyri Scheuten, T. rhenanus (Oudms.), Amblyseius fallacis (Garman), Phytoseiulus macropilis (Banks), Amblyseius finlandicus (Oudms.); and Raphignathidae: Mediolatta novae-scotiae Nes. The chemicals include fungicides, acaricides and insecticides.

The Engelmann spruce weevil, Pissodes engelmanni Hopkins, is an indigenous pest of spruce regeneration in western Canada and the adjacent United States. It is univoltine, overwintering as an adult in the duff beneath the host trees. Eggs are deposited in feeding punctures in the terminal leader. Larvae feed downward in the phloem causing two or more years loss of height growth. Deformities incurred by three or more consecutive years of weevil attacks produce a tree of no commercial value. The incidence of weevilling is most numerous in open grown, even-aged, young stands. Of 14 insect parasites and one predator, Dolichomitus terebrans nubilipennis (Viereck), Eurytoma pissodis Girault and Lonchaea corticis Taylor are considered principal natural control agents.

Microscopic examinations revealed that free-floating hard black bodies in larvae, pupae and adults of the Swaine jack-pine sawfly, Neodiprion swainei Midd., often contained polyhedra. A simple and rapid method for detecting the presence of the virus infection before gross symptoms appear is described.

Eggs of Rhagoletis pomonella (Walsh) laid in Siberian crab, Malus baccata Borkh., hatched, but the larvae did not develop beyond the first instar. The small amount of feeding indicated that death occurred within a few days after hatching. Similar incidents of complete mortality occurred in the crab apples of Malus toringoides Hughes, Dupont Flowering, Henrietta Crosby, and Almey that were infested in the laboratory. Larvae were able to complete their development in the crab apples of Bedford, Pink, Beauty, Dolgo, Virginia, and Chestnut. The causes of this mortality are unknown.

The use of Dry Ice (solid CO2) for immobilising adult houseflies and the use of all-glass handling and holding systems contribute to simplification of the general bioassay procedure with small control mortalities.

Crinophleba rostrata, a new genus and species of a phorid fly from New Brunswick, Canada, is described.

Volume 98, 1966

Page 1277, second line from bottom of page for duct read diverticulum.