An illustrated account of the thoracic mechanism of the milkweed bug, Oncopeltus fasciatus (Dallas), is given. The thoracic skeleton including legs and wings is described and this is followed by a discussion of the interaction of these parts with the musculature. The action of the extrinsic and intrinsic leg muscles, being well known, is tabled as are also the origins and insertions of all the thoracic muscles.

The morphology and fine structure of the stylets, labial clamp, and crumena of the balsam woolly aphid, Adelges piceae (Ratz.), are described from sections studied in the electron microscope.

The synthetic ability of type-A neurosecretory cells (NSC) and corpus allatum (CA) was investigated autoradiographically in both normal virgin females and those from which the frontal ganglion had been removed. Incorporation of 3H-cystine and 3H-uridine into the NSC was significantly lower in frontal ganglionectomized insects than in controls. There appeared to be no relationship between the level of isotope uptake and the amount of stainable material in the NSC. Ability of the CA to incorporate 3H-uridine seemed unaffected by the operation.

This species is a member of the Delininae whose species with known life histories all attack plants belonging to the Liliaceae and Orchidaceae. Eggs are laid singly or in groups of up to 15 eggs on the abaxial surface of Veratrum viride leaves. Larvae produce extensive blotch mines as they feed upon the mesophyll layer. Puparia are formed in the soil, and the pupa is the overwintering stage of this univoltine species. A table outlining larval attributes of the Scatophaginae and Delininae is given.

The two primary functional response models extant in recent entomological literature were compared using a common set of data. Use of an iterative least squares parameter estimation routine was shown to be essential to a comparison of these two models. With parameters properly determined, the Watt model fit data on one out of five experiment days best, the Holling model fit data best on four out of five experiment days. The "handling time" submodel was shown to require iterative least squares parameter estimation rather than the usual log transformation and subsequent fitting of this logistic function by standard linear regression techniques. The conclusion was reached that if accuracy in prediction by nonlinear functional response models is desired, proper methods of determining parameter values are of critical importance.

Pleolophus basizonus (Gravenhorst) is a parasitoid from Europe introduced in Canada and liberated between 1939 and 1949 to supplement natural mortality factors of sawfly populations. Three recoveries reported in the literature show that the parasitoid has dispersed 81 km at 4.3 km per year in Ontario, between 109 and 161 km at 4.5 and 5.6 km per year in Quebec, and 172 km at 8.6 km per year in Michigan. Dispersal occurs by walking, possibly by short flights and by water while the parasitoid is within the host cocoon. Female parasitoids do not fly unless disturbed and dispersal by water cannot account for their movement in Quebec. In observation trays, the mean rate of travel on the ground by female parasitoids was 20.9 cm per minute. This speed is sufficient to account for the rates of dispersal recorded in the field. The parasitoid was present in every jack pine stand sampled between 1965 and 1968 in the western part of the St. Maurice River watershed in Quebec. The most abundant host was Neodiprion swainei Middleton. Absolute population estimates indicate that the parasitoid responds positively to host density and that it is an important addition to the native parasitoid complex.

Larvae are reared on a synthetic diet in 1 oz. ribbed plastic cups. To eliminate the task of placing individual larvae on food, small gauze patches containing 25–40 larvae are placed in the cups prior to emergence from hibernacula. Larvae establish feeding sites between the ribs and are relatively undisturbed by others in the cup until the fifth instar. For maintenance of rearing stock the number of larvae is reduced to six to eight per cup, and they are allowed to pupate in the cups. Up to 100 pairs of pupae are placed in screened cages for adult emergence, mating, and oviposition. When the adults emerge balsam fir foliage is introduced and most of the eggs are deposited on the needles. Needles or twigs with egg clusters are transferred to large dishes the inside of which is painted black. The dish is tightly sealed with parafilm to which small gauze patches are attached and then placed under artificial lighting. The newly-hatched larvae are attracted toward the light and spin hibernacula in the gauze. The parafilm and gauze are sealed in plastic bags for cold storage treatment. By this system up to 10,000 larvae per week are easily produced.A discussion on the selection of rearing stock, rearing conditions, rearing containers, and the use of anti-fungal agents is included in the report.

Lipoptena pudui n. sp. was taken from the cervid Pudu pudu (Molina), in central Chile. This is the first ked-fly known from this species of pygmy South American deer. The new species is closely related to L. guimaraesi Beq. and is characterized chiefly by the long narrow palpi and the non-constricted pronotum. A revised key to the New World species of Lipoptena is presented.

Residue analysis of forest soils sprayed once at 1 lb/acre showed little breakdown of DDT through 9 years after application. In the absence of appreciable downward trend, residue persistence could not be estimated beyond stating that it appears to persist much longer than the 10 years suggested by others. Persistent residues are largely restricted to the upper soil litter. Residues pass from soils to earthworms to robins throughout the 9-year period studied. It is suggested that this relationship may persist for as long as 30 years after a single application to the forest. Biological magnification of residues in robins is demonstrated. Significance of these residue levels is discussed.

The larva and pupa of Glutops rossi Pechuman are described. Because of their remarkable similarity to the same stages of Pelecorhynchus Macquart, as well as many similarities in their adults, the genus Glutops Burgess is transferred from the Xylophagidae to the Pelecorhynchidae.

Penetration of topically applied DDT-C14, at dosages varying between 35 and 2900 nanograms, into individual house flies was studied at 2, 6, and 24 hour intervals. The rate of penetration was found to be dose dependent and not exponential even when nanogram quantities of the chemical were used.

Controlled mating experiments demonstrating total reproductive isolation, together with consistent differences in morphological and cytological detail, confirmed the validity of the closely related group IX Ips: grandicollis, cribricollis, lecontei, montanus, confusus, paraconfusus, and hoppingi. The latter two species, new to science, were formerly considered to be confusus.Matings between grandicollis from eastern Canada and North Carolina were subnormally fertile; other intraspecific matings between individuals of the same population or distant populations produced fully fertile progeny. Interspecific pairings usually resulted in insemination and normal-appearing egg galleries, but, with one exception, none of the eggs hatched.One montanus and two confusus, each mated by males of the same species, produced all-daughter broods. This "sex-ratio" condition appeared to be the result of a matrilineally transferred cytoplasmic factor lethal to male embryos only.At first meiotic metaphase all species had the karyotypic formula 15 AA + Xyp, and only grandicollis was easily differentiated by bivalent configuration or size sequence. Most other species showed diagnostic differences at meiotic prophase or second meiotic metaphase. Pairing disruptions and anaphase bridges occurred in grandicollis interpopulational hybrids; meiosis was normal in progeny from interpopulational pairings of confusus, paraconfusus, and montanus.In grandicollis the median struts of the male genitalia were 1.5 times longer than the median lobe. The struts/lobe ratios for other species approximated 1.00 but differences for most comparisons between species were statistically significant. The shape of the pars stridens on females was different for most species and mean widths of striations thereon ranged from 0.517 μ for paraconfusus to 0.876 μ for lecontei. This character provided absolute discrimination of females of confusus from those of paraconfusus and hoppingi but the latter two species were most easily separated by differences in the density of punctures in the elytral declivity.It is hypothesized that contiguous allopatry and differences in host and ecological specialization, evidenced in species of group IX, is maintained by their high propensity for interspecific mating which fails completely to produce progeny.

Schistocerca gregaria possess four neurones of giant fibre proportions within the abdominal ventral nerve cord. These fibres arise from single cell bodies in the terminal ganglionic mass and pass without interruption to the metathoracic ganglion. Fibres become reduced in diameter when passing through a ganglion. Branching of the giant fibres occurs in abdominal ganglia 6 and 7.

The genus Glutops Burgess is here considered to comprise eight species, three previously described from North America, a Japanese species transferred through synonymy, and four western North American species herein described as new. A key to the eight species is given.

Larvae of Pseudaletia unipuncta (Haw.), reared on corn foliage, were found to vary in the rate they were able to feed, grow, and attain maturity. Mortality varied inversely with the rate of food intake. In the fifth and sixth instars, there was a direct linear relationship between rate of food intake and daily growth, and rate of food intake and daily development. A variance of 78 to 96% in final weights of the two stages was explained by the combined effect of initial weights of larvae, food supply, duration of feeding, and food ingested. Fecundity increased with the rate of food intake of the larvae.When P. unipuncta feeds at a high rate, it is able to accelerate development, increase growth, and maintain a high reproductive potential. When the rate of food intake is low, development, growth, and fecundity are reduced for the sake of survival.

Measurement of radioactivity immediately after application on house fly puparia was found to be the most accurate measure of the weight of radioactive insecticide applied topically and resulted in precise evaluation of the data. Use of radioactive chemicals and microcoulometric determinations indicates that considerable quantities of DDT-14C, heptachlor epoxide - 14C, and lindane-14C, volatilize from applied surfaces, a factor which should not be neglected during penetration studies. Metabolites of DDT were studied by GLC. Only DDE was obtained from flies which emerged from treated puparia of a DDT-resistant strain. Puparial washing 24 hours after treatment yielded some DDE indicating partial metabolism of DDT to DDE on the surface of the cuticle.

A new species, Ibalia gigantea, is described from material received from the Forestry Station in Calgary, Alberta, and from the Canadian National Collection in Ottawa.