The infuscatus group comprises 20 species and 2 subspecies. The group is wholly American, the main habitats occurring in the dry parts of the U.SA. and Mexico. Only Philodromus infuscatus Keyserling reaches Canada, while a few species are neotropical. P. droseroides Schick is divided into P. d. droseroides of California and P. d. arizonensis ssp. n. of Arizona. Similarly P. infuscatus is divided into P. i. infuscatus of eastern U.S.A. and P. i. utus Chamberlin of western U.S.A. The following are described as new species: P. pratarioides, P. harrietae, P. mississippianus, P. separatus, P. tortus, P. probolus, P. infectus, P. longiductus, P. breviductus, P. pseudanomalus, P. mexicanus, and P. cavatus. P. dispar Walckenaer, a species introduced from the Old World, is the sole American representative of the dispar group.

Studies in a Douglas-fir stand showed that the crepuscular flight pattern of Gnathotrichus retusus (Lec.) and G. sulcatus (Lec.) depends upon an interaction of light intensity and temperature. After the primary temperature threshold of 58°F is reached, light intensities above 2,000 ft-c retard flight activity, while both higher light intensity and darkness terminate flight.

Bio-assay showed that the pheromone of attractive female Trypodendron lineatum (Oliv.) must be produced in the posterior part of the ileum. Histological studies revealed a layer of secretory cells in the rear part of the ileum and the rectal valve which occur only in feeding adults. The attractive material is produced only when bark and wood particles are present at the site of pheromone production, and the actual production is initiated probably by activity of a female hormone or enzyme.

In Mexico during the spring of 1950, four imported species of parasitic Hymenoptera (Amitus hesperidum Silvestri, Prospaltella smithi Silvestri, P. clypealis Silvestri, and P. opulenta Silvestri) were placed on populations of their natural host, the citrus blackfly, Aleurocanthus woglumi Ashby. Their artificial distribution and establishment throughout areas in which the host species was extremely abundant and the observed adjustment of each to its host, to its competitors, and to distinctive regional environments revealed physiological and ecological factors that determined the dominance of one species over another. These factors and the circumstances of their occurrence during 1948 to 1953, inclusive, as reported by Herbert D. Smith, Entomologist of the United States Department of Agriculture, are reviewed and amplified.

Five particle types of tetradiphon, three of chloropropylate, and two of Pentac (bis(pentachloro-2,4-cyclopentadien-1,yl) were prepared in similar formulations and tested as sprays against different stages of Tetranychus urticae Koch on bean leaves. The residual, combined topical and residual, and the systemic effects of the formulations were recorded. The target sizes presented by T. urticae stages and by the ranges over which they moved and fed were determined and the numbers of particles per unit area deposited on bean leaves by the formulations used, counted. Positive correlations were shown in all instances between smallness of particle size, number of particles per unit area, and effectiveness, but the relationships between these factors were complex. It is concluded that effectiveness is influenced by a number of factors of which particle size and shape are two which are important but that their effects are often greatly modified by some of the other factors.

Sitka spruce produces twice as many needles per linear inch of twig as western hemlock. Defoliation by the black-headed budworm, Acleris variana (Fern.), is more severe on hemlock than spruce because of differences in the phenological development of the hosts and in the feeding behavior of first- and second-instar larvae on each of the hosts.

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.

One new species, Acanthoscelides tridenticulatus, is described from Mimosa strigillosa Torr. and Gray in Texas, and from specimens collected in Louisiana and Texas.Erroneous records of Bruchidae having been reared from native Mimosa in the United States are corrected. These are: Merobruchus julianus (Horn) (Not synonym Bruchus ochreolineatus Fall) from Acacia greggii Gray, Not Mimosa fragrans; Acanthoscelides chiricahuae (Fall), Not Bruchus schrankiae Horn, from M. borealis Gray; and A. distinguendus (Horn) from Rhynchosia americana (Mill.) Metz, NOTM. strigillosa. All of these constitute new host records.The following new host records are reported: Acanthoscelides chiricahuae (Fall) from Mimosa biuncifera Benth. in Texas, New Mexico, Arizona, and Coahuilla, Mexico; and from M. dysocarpa Benth. and M. grahamii Gray in Arizona, A. quadridentatus (Schaeffer) from M. pigra var. berlandieri (Gray) Turner and M. strigillosa in Texas, and from M. pigra var. pigra L. in Nicaragua and Panama. A. speciosus (Schaeffer) from M. malacophylla Gray in Texas, from M. biuncifera in Arizona, and from M. galeottii Benth. in Morelos, Mexico. Stator pruininus (Horn) from M. biuncifera in Texas and Mexico; and from M. dysocarpa in Arizona.

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.

A 5-year study of Laspeyresia pseudotsugae n. sp. (Lepidoptera: Olethreutidae) yielded considerable data on the habits, life history and immature stages of this insect, which gained attention because of its conspicuous bark-mine scars on the trunks of young Douglas-fir trees, Pseudotsuga menziesii (Mirbel) Franco. The mines are not deep enough to cause serious damage. L. pseudotsugae has a 1-year life-cycle. Three species of ichneumonid parasites were recovered, and several predators were identified.

Habrobracon lineatellae Fischer has been imported from Lebanon into California in the course of a project on the biological control of the peach twig borer, Anarsia lineatella (Zeller). The navel orangeworm, Paramyelois transitella (Walker), is used as a host to mass-culture this parasite. Its biology is similar to that of other species in the genus, for the female paralyzes the host before oviposition and the larvae develop ectoparasitically. Females begin to paralyze hosts 2 to 26 days after emergence, and oviposition is initiated 1 day after they begin this host paralyzation. The number of eggs per female varies from 32 to 954. A maximum of 12 larvae of H. lineatellae can develop on 1 larva of P. transitella. When virgin females are held for 4 days and then placed with sexually active males for the rest of their lives, the sex ratio of the progeny is 53% female. The adults do not host feed. Females fed honey–water live an average of 105 days (range 51 to 166 days).

The male of Xysticus rugosus Buckle and Redner, 1964, is described for the first time, the diagnostic parts of the palpus are drawn, and a key is provided for distinguishing the males of the Nearctic species of the Xysticus labradorensis group.

Egg-protein patterns from 23 insect species representing seven orders were obtained by acrylamide gel electrophoresis. The patterns were species specific and highly reproducible. Those for congeneric species were very similar and family resemblances were apparent. The usefulness of egg-protein patterns in phylogenetic studies and in the analysis of closely related species was suggested.

Two species of Olethreutinae (Tortricidae), Olethreutes inquietana and Olethreutes mengelana, are known to occur in the far north. Their respective hosts are Pedicularis and Dryas. Life-history notes on inquietana, and larval descriptions and illustrations of both species are given in this paper.

The behavior of the balsam woolly aphid in relation to its dispersal and establishment is reported. Light orientation trials provided no evidence that crawlers move over their host in a distinct manner. But the number of crawlers that drop from their host increases with light intensity and temperature. Crawler activity may also influence dropping, but activity declines rapidly with increasing age particularly at higher temperatures. Populations along stand edges are probably more subject to long range dispersal.

The morphology and fine structure of the maxillary and mandibular stylets of the green peach aphid, Myzus persicae (Sulzer), are described from sections, whole mounts, and two-stage replicas. The mechanisms of penetration of the host plant are discussed.

High mortality occurred in the blood-sucking bug Rhodnius prolixus Ståhl after feeding through an artificial membrane on defibrinated mammalian blood containing injectable antibiotic mixtures.

Chrysobothris orono Frost, a buprestid which attacks living red pine (Pinus resinosa Ait.) and jack pine (P. banksiana Lamb.), has a 2-year life cycle and two separate broods in Michigan. Adults emerge from May to July. The eggs are laid singly, usually on the southwest side of a tree; the fifth and sixth whorls from the top are the preferred oviposition sites. Larval eclosion usually occurs in early June. Each larva excavates a cell in the bark and causes the flowing pitch to coagulate into a large pitch mass. The first three instars feed in the bark and the last two instars feed in the xylem. Advanced larvae may reach the fourth instar by fall of the first year; overwintering occurs in the third and fourth instars. The fifth instar, which appears in the spring of the second year, bores a short L-shaped gallery in the xylem and plugs it with frass and wood chips to form a pupal cell. It pupates in the spring of the third year. Adults emerge by chewing through the plug and pitch mass. The bark cell and xylem gallery seldom injure the tree directly, but they remain as defects in the bole after the wounds have healed. Because damage is slight and the insect population low, C. orono is not likely to become an important forest pest.

Radionuclides may be used as ecological tracers to study trophic–level relationships. To use cesium-137 to investigate the role of the giant water bug, Lethocerus americanus (Leidy), in the food-web of a small pond, it was necessary to measure the elimination rate of the nuclide. The experimental determination of the elimination rate of cesium-137 in fourth instar and adult water bugs, and the calculation of the fraction of ingested food assimilated is described.