The wing folding mechanism was investigated after a detailed study of the wing base morphology had been made (Sharplin, Canad. Ent. 95: 1024; 1121). Living moths were observed with a binocular microscope equipped with a micrometer eyepiece.

The first and second axillary sclerites do not move anteroposteriorly; only the distal half of the wing base is involved in wing folding. The folding muscle originates on the pleural ridge and inserts on the third axillary sclerite. The movement of the third axillary is communicated to the bases of the anterior veins through the median plates. The radial plate rotates around the ventral second axillary sclerite which lies underneath the radial bridge at point p, (Fig. 1). Bending cuticle allows the radial bridge to buckle when the wing is folded. The first median plate ( Ml ) rotates about its articulation ( f ) with the dorsal second axillary sclerite. The distal median plate (M2) passes underneath the second cubitus and is fused to the radius. This connection to the radius restricts the backward movement of the second median plate so that point e instead of following the wider arc eg of a circle with its centre at f, must follow the arc cegd drawn about pivot p. The median plates are bent upwards during wing folding and their effective length is shortened so that they can follow the shallow arc epg. When point e is in position g the posterior margin of the median plates is straight, although the anterior margin remains arched causing the median plates to be buckled, (Fig. 2).

Resorption of terminal oocytes was investigated in 3 species of grasshoppers, Melanoplus femurrubrum femurrubrum (DeGeer), M. scudderi (Uhler), and Hippiscus ocelote (Saussure). Significant differences in percentage resorption were found between species. Anterior ovarioles resorbed terminal oocytes more frequently than ovarioles in the middle and posterior regions of the ovaries. Resorption of terminal oocytes due to differences in relative ovariole age does not appear to be a factor in percentage resorption based on the lengths of developing terminal oocytes. There was no difference in percentage resorption of terminal oocytes between ovaries.

Descriptions are provided for larvae of nine species of Ceratophyllus Curtis for which swallows in North America, north of Mexico, are recorded hosts. A detailed description is provided for the larva of Ceratophyllus celsus celsus Jordan and for other species only where there are significant differences from C. c. celsus. Ceratophyllus celsus celsus, Ceratophyllus scopulorum Holland, and Ceratophyllus petrochelidoni Wagner are characterized by a large number of anal comb (25–42) and anal mound (13–23) setae, but among themselves have not proved separable; Ceratophyllus styx riparius Jordan and Rothschild is remarkable in having two ventral plate setae on all thoracic segments as well as on the eighth and occasionally the ninth abdominal segments; Ceratophyllus idius Jordan and Rothschild and Ceratophyllus niger C. Fox characteristically display stout ventral plate setae on the thoracic segments, as seen in C. c. celsus, but have fewer anal comb and mound setae. We are unable to separate larvae of C. idius and C. niger from each other. Ceratophyllus gallinae (Schrank) also has few comb and mound setae, but the ventral plate setae are more slender than evident in other species treated here. Ceratophyllus diffinis Jordan and Ceratophyllus garei Rothschild, the sole Nearctic representatives of the subgenus Emmareus Smit, are characterized by their short, slender, thoracic ventral plate setae, but have not been separated from each other here. Redescriptions are provided for larvae of C. gallinae and C. garei. Descriptions for all other taxa are provided for the first time. A key is provided to the known larvae of species associated with swallows in North America, north of Mexico.

Radiocesium accumulation by Aedes aegypti larvae was greater at 25 °C, than at 20 °C. The activity density (c.p.m./mg dry wt.) of the adults was the same for both sexes, as was the nuclide’s elimination rate. The amount of 137Cs accumulated by the larval instars was inversely proportional to the concentration of potassium in the rearing medium, the suppression of 137Cs uptake being greater at 25 °C than at 20 °C. The possibility that larvae may accumulate 137Cs via the anal papillae and the gut, is briefly discussed.

The discovery of the “European spruce sawfly” in Canada in 1930 and the development of its destructive outbreak have been described (3). It was identified in 1931 as Diprion polytomum (Htg.), which became Gilpinia polytoma (Htg.) in 1939 as a result of Benson's revision of the genera of the Diprionidae. The work of parasite introduction (1) commenced immediately on the assumption that the insect was an importation from Europe.

The endemic Galápagos’ genus Neoryctes Arrow has had a confused nomenclatorial and taxonomic history. Evaluation of morphological variation in the 41 specimens now available confirms the distinctiveness of the genus and establishes the existence of four species, each restricted to a single island. The original Darwin specimen, named Oryctes galapagoensis by G.R. Waterhouse in 1845, is shown to be from Isla Santiago. Two other names are valid: N. linelli Mutchler for the population on San Cristobal and N. moreti Dechambre for the one on Santa Cruz. The population on Floreana is named as a new species, N. williamsi. Neoryctes most likely originated from a Pentodontini dynastine ancestor from lowland South or Central America. The ancestor first dispersed to Isla San Cristobal, one of the oldest islands. It is hypothesized that before hindwing reduction occurred, which is now characteristic of all members of the genus, individuals from San Cristobal spread to the other islands. Subsequently, possibly during periods of Pleistocene aridity, each population became restricted to its present range in the moist highland zone of an individual island.

This study provides information on the species of Chrysocharis (Kratochviliana) found in North America with special emphasis on the Canadian species attacking the birch casebearer, Coleophora serratella (L.) (= fuscedinella Zeller), and the birch leafminer, Fenusa pusilla (Lepeletier).

The genus Chrysocharis Förster in North America north of Mexico consists of two subgenera, Kratochviliana Maláč and Chrysocharis s. str. There are 15 Nearctic species of Kratochviliana, of which 10 species are described herein as new. These are: C. (Kratochviliana) robusta n. sp., C. (K.) incerta n. sp., C. (K.) stipitis n. sp., C. (K.) hirsutiventris n. sp., C. (K.) walleyi n. sp., C. (K.) protolithocolletidis n. sp., C. (K.) milleri n. sp., C. (K.) aluta n. sp., C. (K.) coptodiscae n. sp., and C. (K.) cuspidigaster n. sp. Relationships and distribution of species-groups in North America and Europe are discussed. Keys to subgenera and species and host records are included.

A window flight trap was altered by replacing a collecting fluid trough with a horizontal cylinder, covered at both ends with clear plastic or screen. Insects falling into the cylinder move toward the light at the ends and are readily-collected. Sample data illustrate the usefulness of the traps for collecting scolytid beetles.

Euxestonotus error (Fitch) (Hymenoptera: Platygastridae) is considered part of the natural enemy complex of the wheat midge Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae). Although previously reported in the United States of America, there is no record for this species outside the state of New York since 1865. A survey conducted in the summer of 2015 revealed that E. error is present in northwestern Montana and is likely playing a role in the suppression of wheat midge populations.

Male. Very similar in all respects to guttata McD. but noticeably larger in size. Thorax deep blackish, tinged with brown in the pleural sutures. Abdomen with segments 2-6 and anterior portion of 7 whitish, hyaline, with considerable brownish shading on 2. In place of the lateral black dots of guttata there is a short black transverse streak in the postero-lateral corner of segments 2-6 with some slight brown suffusion anterior to it, especially on segment 2. Rear segments deep chocolate-brown.

Parasitism of pupae of G. mellonella (L.) by P. turionellae (L.) was found to prevent adult emergence. The effect was manifest within 24 hours of parasitization. Experiments are described which indicated that the source of the factor preventing eclosion of the imago is the developing parasite egg.

The paper describes an observation chamber and air-conditioning system designed for studying the responses of flying insects at the boundary between two microclimates. Two vertical air streams each fill one half of the rectangular observation chamber. Turbulence is carefully removed so as to maintain a sharp boundary between the streams. Each stream is separately conditioned by passage through heat exchangers and plastic sponges impregnated with substances to be vapourized. Responses of flying insects are studied both photographically and by counting rates of turning at the boundary.

Comparisons were made of frequency distributions of Ips avulsus (Eichh.) and Ips grandicollis (Eichh.) caught in window traps while these species were attacking fresh pine slash. Relationships between mean and variance of trap data indicated that the flight of I. avulsus was more highly aggregated than the flight of I. grandicollis. Three different indices of aggregation were calculated which quantitatively expressed the degree of flight aggregation in each species. Degree of aggregation during attack may be an index of aggressiveness since it determines beetle density which influences attack success on a living host. The relatively high degree of flight aggregation of I. avulsus may partly explain why this species is more frequently a killer of live trees than is I. grandicollis.

During the summer of 1930 it was observed that large numbers of eggs of the Oriental fruit moth (Laspeyresia molesta Busck.) were being destroyed by some enemy which pierced the shell and sucked out the contents. The presence of many chrysopid larvae on the trees indicated that these might be responsible for the destruction of the eggs.

Records are presented on twenty nests of Megachile pugnata Say obtained from sumac stick trap-nests. These nests were distinctive as, unlike most Megachile nests, the cells were not constructed from pieces of cut leaf. Instead, the cells were made with basal and apical partitions consisting of leaf discs, chewed leaf materials and soil. Each finished nest contained an empty vestibule and had an orifice plug. The sequences of males and females, and the natural enemies of this species were determined by rearings. Females normally preceded males in the sequence of cells. The species was parasitized by Coelioxys alternata Say and Leucospis affinis Say. The mean number of cells in the nests was 3.5. There is one generation a year in Wisconsin.

We found larvae of Chylizasplendida Iwasa (Diptera: Psilidae) feeding on galls induced by Asphondyliabaca Monzen (Diptera: Cecidomyiidae) on the buds of Weigelafloribunda (Sieb. & Zucc.) K. Koch (Caprifoliaceae) in Japan. This is the first confirmed report of cecidophagy in the Psilidae.

Counting hemlock looper (Lambditm fiscellaria lugnbrosa) eggs attached to moss samples is tedious and inaccurate. Moss samples treated with a 0.5% NaOH solution for 1 minute releases the eggs, which can be washed and filtered out of the moss. Other debris can be separated through differential flotation with 15% NaCl solution. Three such washings provide data for analysis with the maximum likelihood method, producing density estimates with low-standard errors.

The extent and intensity of the present infestation of the spruce budworm, Archips fumiferana Clem., in eastern Canada has become a problem of immense national concern (I). The necessity for further knowledge in formulating adequate control programmes has emphasized the importance of considering the possible utilization of natural insect parasites. As part of the more conprehensive study of control being carried on by the Federal Division of Entomology, the Dominion Parasite Laboratory in cooperation with the Forest Insect Unit instituted a programme of parasite introduction in 1943.

Sampling techniques for estimating egg populations of the clover root curculio, Sitona hispidula (F.), were developed in alfalfa and red clover fields in Kentucky. An appropriate sample unit was a 3 × 3 in. (7.6 × 7.6 cm) area of plants and the soil beneath it to a depth of 4–5 in. (10.2–12.7 cm). This was processed by a flotation technique. The spatial disposition of the eggs conformed to a clumped pattern in both fields. The variation of 88 to 93% in log variances was accounted for by the variation in log means. There were no significant differences in dispersion pattern between the two crops. Variance analysis revealed that block and plot differences were rarely significant but the interquadrat variance predominated. The number of samples required to estimate the population with specified level of significance and margin of error was inversely proportional to population density.

In studies on introduced parasites of the European pine shoot moth, Rhyacionia buoliana (Schiff.), in Waterloo County Reforestation Area, near Elmira, Ontario, casual observations showed that some stages of the shoot moth were attacked and eaten by several arthropods. Preliminary studies were initiated in 1958 on population estimates and feeding activity of five predatory groups and were resumed on a larger scale in 1959 with six groups. Results of these studies are described below.