The opisthosomal musculature of adult female Araneus diadematus Clerck was investigated by means of dissections. Forty-nine different muscles, each paired, were found in the opisthosoma proper. Of these muscles, 7 pairs move the opisthosoma about the pedicel, 13 pairs compress the opisthosoma, 19 pairs move the spinnerets and colulus with respect to the opisthosoma, 4 pairs dilate the anus, 3 pairs dilate the genital aperture, and 3 pairs open the book-lung spiracles.

Of the methods designed to detect and measure the intensity of direct and delayed density-dependent types of mortality acting on populations, that of Morris has gained considerable acceptance. While this method of analysis has predictive value and provides a means of estimating direct density-dependence, it seems inappropriate to the detection and measurement of a delayed density-dependent mortality such as that normally associated with entomophagous parasites. The biological significance of the slopes of the linear regressions calculated in the Morris method is discussed, and population models based on the theory of Nicholson and Bailey are presented in support of the argument.

Regression coefficients derived from the Nicholson–Bailey parasite mode) by Hassell and Huffaker (1969) are interpreted, and their conclusions about the biological significance of changes in slope are shown to be invalid. It is demonstrated that the term "delayed density-dependence" has no functional significance because it includes density responses that range from inverse to direct, depending upon the particular theoretical model that is selected for simulation exercises. In natural populations of a number of forest insects, the net response of parasitism to host density is direct, not inverse.

Upon transfer to a photoperiod of LD 12:12 all young, reproductively active Chrysopa carnea Stephens, reared and maintained under LD 16:8, showed a rapid decline in fecundity. One group entered diapause, as shown by the cessation of oviposition within 22 to 34 days, fat body accumulation, and an associated colour change. The females in this group resumed oviposition within 3 to 7 days after being returned to LD 16:8. Females in the other group under short-day conditions continued to oviposit, but at a lower rate than those kept under constant LD 16:8. Our data indicate that the imago is sensitive to both long-day and short-day photoperiods and that some males and females enter a facultative reproductive diapause which is induced and terminated in this stage solely by manipulating the adult lighting regimen.

The diet of the common shrew contained significant proportions of lepidopterous remains, and these were mostly of winter moth. The least shrew also at times preys heavily upon winter moth. Calculations indicate that predation by mammals, especially common shrews, could have important consequences on the population dynamics of the winter moth. It was concluded that there is only slight interaction between winter moth predation by shrews and predacious beetles.

In a 3-year study, one annual application of a 10% granular formulation of disulfoton in the soil at a rate of 2 lb actual toxicant per acre controlled M. persicae throughout the entire period that aphids were most prevalent in pepper fields. Some control was observed within a few days of treatment, but effective control did not occur until 2 to 3 weeks after placement of the insecticide. Irrigation increased the initial uptake of disulfoton, but after 2 weeks the degree of control was essentially the same in irrigated and nonirrigated plots.Analyses of fruit samples from treated plots showed that there were no detectable amounts of disulfoton or its oxidation products 42, 50, and 60 days after treatment. These observations suggest that the required interval of 90 days between treatment and harvest could be reduced. Appreciable amounts of the insecticide or its oxidation products were present in the leaves on all sampling dates.

Enoclerus barri Knull occurs in western North America from British Columbia south to Mexico and throughout the Rocky Mountain region. Adults were collected at Grass Valley, Calif., from May to September at traps baited with beetle attractants. Collections occurred at temperatures ranging from 22.5° to 31 °C; the sex ratio of trapped beetles was 4.5 females to 1 male. Duration of life cycle stages at 24 ± 2 °C were: egg, 9 days; larva, first iastar, 14 days; second instar, 12 days; third instar feeding stage, 14 days. All larvae reared to third instar failed to pupate in the laboratory. Adult females of unknown age when collected lived from 10 to 131 days and produced an average of 389 eggs per female. Enoclerus barri utilized six species of Scolytidae as hosts in the laboratory.

Nymphs and adults of Podisus maculiventris (Say), reared on four sizes (diet levels) of live larvae of Galleria mellonella (L.), captured prey, consumed food, and grew at rates varying with the size of larvae supplied. For nymphs, a direct linear relationship was obtained between rate of food consumption and daily growth and rate of food consumption and daily development. For adults, male and female, age did not affect food intake significantly, but for females alone, food intake differed significantly at different diet levels. A significant difference was also obtained for both sexes between body weight and diet level. Males and females lived longest on diet 1, apparently because of reduced metabolic activity.The number of eggs laid by each female corresponded to its food consumption for the first 35 days but decreased thereafter with age. The mean dry weights for fertile and infertile eggs at different diet levels did not differ significantly irrespective of the amount of food consumed by egg-laying females.For each nymph in each of instars 2 to 5 and for adults, the consumption quotient, an index of metabolic activity, increased as the rate of food consumption increased. For nymphs, the quotient decreased during ontogeny at each diet level, and for adults, decreased with age at diet levels 2, 3, and 4. The quotient remained constant for adults of both sexes at diet level 1.Results show that nymphs and adults of P. maculiventris can survive and mature satisfactorily for extended periods on small prey but needs larger prey to accelerate development, increase growth, and maintain a high reproductive potential.

Most Empididae are predators on living insects, but a few instances of other feeding habits have been discovered. It is shown that Anthalia bulbosa (Ocydromiinae) eats the pollen of several flowers, and other possible cases of pollen-eating in Ocydromiinae and Empidinae are discussed. Micropborus obscurus (Empidinae) feeds on dead insects trapped in spiders’ webs, in agreement with Laurence’s finding for M. crassipes; and several reports of Clinoceratinae feeding on dead insects at the water’s edge are assembled. This diversity of feeding habit finds a parallel in Ceratopogonidae.In Empididae the protein-rich meal, whether of insect prey, dead insects, or dead pollen, is taken in typical cases by both males and females, as would be expected on systematic grounds. The sexual differentiation of hunting and feeding habits (males hunting, perhaps not feeding; females non-hunting, receiving prey by transfer at mating) is a specialized feature restricted to the Empis–Hilara–Rhamphomyia group (Empidinae).

Feeding activity is a crucial measure used in experiments with larvae of Pseudosarcophaga affinis auct. nec Fallén on chemically defined diets to determine whether food selection and preference occurs because of nutritional factors. To avoid temporal bias in recording it was necessary to know: (1) when during larval development feeding activity is greatest; and (2) whether a diel periodicity of feeding activity demands that observations be standardized according to time of day. Experiments done at 23 °C and 16-hour photoperiod with new-born larvae showed that: (1) during larval life feeding activity increases rapidly up to 96 hours of age and thereafter slowly decreases; and (2) on the two diets tested more feeding occurred during darkness but only on one diet was the difference (about 7.3%) statistically significant. Thus in P. affinis it is seldom necessary to control for time of day in experiments of the kind used in the work on food selection and preference.

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.

Megachile rotundata (F.) is a domesticated bee used to pollinate alfalfa in southern Alberta. There it may have four species of parasites, all chalcidoids. These parasites are removable by water traps before the hives are set in the field. Three of these parasites, Monodontomerus obscurus Westw., Dibrachys maculipennis Sz., and Pteromalus venustus Wlkr,, are European in origin. The first seems not to be established in Canada; the latter two have been reared from Canadian species of Megachile and thereby may prove a source of parasitism. The fourth species, Melittobia chalybii Ashm., is a widespread, nearctic, multivoltine species and is known as a laboratory pest of hymenopterous nests; it is likely to be the major parasite in rotundata nests. A key is given for the parasitic species.

Drawing retrospectively and collectively on results of a single individual and his associates covering some 22 years of field and laboratory studies, the authors present three documented case histories of technically complete biological control. They use these examples to illustrate the potential for greater use of this method of pest control, and they discuss the theory of biological control as related to whether or not introductions of a complex of enemy species will inherently lead to competitive interference and a lesser degree of control than if only the "best" species were introduced. They conclude that the three case histories are a refutation of this thesis, as are certain theoretical considerations, and the net results from all biological control programs on a worldwide basis.The authors also point to weaknesses in the use of currently available methods for quantitatively rating or appraising the control and regulating power of density-dependent factors that act with a lag (entomophagous parasites and predators), and emphasize chat regression and modelling methods should be used in conjunction with "check-methods" or other experimental means.