The generic characters of Eumacronychia are reviewed and as here considered the genus includes 21 nominal forms of which 9 are described as new. All members are quite similar in habitus and difficult to distinguish except by reference to the male terminalia. A key to all known species is included to facilitate identification. The maximum distribution of the genus is centered in the southwestern United States with the present known extreme range extending from Canada to Guatamala.

The family Otopheidomenidae Treat is transferred to the Phytoseiidae Berlese as a subfamily, and the subfamily Macroseiinae Chant et al. is considered as a genus in the subfamily Phytoseiinae. The subfamily Otopheidomeninae contains four genera: Otopheidomenis Treat, Hemipteroseius Evans, Treatia Krantz and Khot, and Entomoseius Nov. The subfamily Phytoseiinae contains 10 genera: Typhlodromus Scheuten, Phytoseius Ribaga, Chantia Pritchard and Baker, Platyseiella Muma, Iphiseius Berlese, Paraamblyseius Muma, Phytoseiulus Evans, Amblyseius Berlese, Macroseius Chant et al., and Gigagnathus Nov. Keys and descriptions of genera are included.

The external anatomy of the larvae and pupae of a number of species of the genus Dendroctonus was studied to determine its value in the classification of the genus. It was found that the larval and pupal characters supported the synonomy proposed in a revision of the genus based on imaginal characters recently published by another worker.

Three different soils – sand, loam and clay – at each of three moisture levels – saturated, intermediate, and dry – were offered to female Melanoplus sanguinipes as oviposition sites. When given a free choice the females preferred moist sand to all other oviposition sites and avoided soil that was completely dry. When no moist soil was available, coarse dry soil was preferred to fine dry soil, but the oviposition rate was reduced. The females would probe and dig at random into any of the soil offered but would withhold their eggs temporarily if the subsurface soil was not moist. Soil water pH appeared to have very little influence on the females' acceptance of an oviposition site as egg pods were deposited in soils with a range of pH from 3.0 to 11.6. It is suggested that although the absence of moisture in the soil may affect the distribution of egg-pods in the microhabitat and may reduce the rate of egg-pod production slightly, the temperature prevailing during the oviposition period is perhaps a more important factor in determining the number of egg-pods deposited.

Since the earliest days of this century the interactions of parasitic Hymenoptera that attack the same host species have been reported from time to time in connection with studies on the natural enemy fauna of pest insects. These studies indicate that the synchronous attack by two or more parasitic species on an individual of a host population, multiple parasitism, is of little, if any, importance in the economy of that population, whereas the attack by two or more parasitic species on a sequence of a host’s developmental stages and instars, sequential parasitism, may be highly important, especially from the standpoint of host regulation. Since the host-regulating capacity of a parasite species may vary both seasonally and geographically, sequential parasitism is highly conducive to continuity in the conservation of the host’s food supply, the practical measure of regulative parasitism. The cooperative as well as the competitive aspects of sequential parasitism are discussed. The parasite fauna of the black scale, Saissetia oleae (Bernard), is used to exemplify these aspects of parasitism.

Group IX of North American Ips contains I. grandicollis (Eichhoff), I. confusus (Leconte), I. montanus (Eichhoff), I. cribricollis (Eichhoff) and I. lecontei Swaine. I. chagnoni Swaine is made a synonym of I. grandicollis (Eichhoff). Ips of Group IX differ from other Ips by having five spines on each side of the elytral declivity. Species are described and a key is given. They breed in various species of Pinus and most of them occur south of the boreal forest.

Predators that have fed on Panonychus ulmi (Koch) and Bryobia arborea Morgan and Anderson can be distinguished by the orange and reddish carotenoid biochromes derived from the prey. Predation on the two species of mites cannot be clearly separated. The predators are squashed on filter paper and the pigments separated by circular chromatography in a mixture of one part of zylene to four parts of white kerosene. The mite pigments are considerably altered during digestion in the predators. The method does not reveal the number of mites consumed by a predator, owing to differences in the pigment content of the various stages of the prey and in the time the pigments are retained in the predators.

Theoretical objections to the hypothesis that polymorphisms are evolved as an adaptation by populations are discussed and upheld. Genetic data do not support the assumption that potency balance systems controlling polymorphisms are widespread in the Lepidoptera and are responsible for the prevalence of polymorphisms sex-limited to the female. It is pointed out that such polymorphisms are commoner in butterflies than in moths and that this requires an ecological, not a purely genetical, explanation. It is suggested that the presence of two potency balance systems in the genus Choristoneura could have resulted from an interchange of genetic material between the X-chromosome and an autosome during the evolution of the group.

Observation of ecdysis in one male and three females of the spider Philodroms rufus Walckenaer (family Thomisidae) has revealed a hitherto unreported source of food for newly molted spiders. After hanging suspended from their exuvia by the spinnerets for a few minutes, the spiders suddenly flexed their legs and ran quickly from base to tip of each exuvial leg, pressing their mouthparts along the limbs. On reaching the tip of each tarsus the spiders bit the old cuticle, allowing a column of colorless liquid that extended through the distitarsus and basitarsus and part way up the tibia to be withdrawn steadily and rapidly. One of the spiders drew the liquid from only four of the exuvial legs, while the others drew from all eight. Having fed, the spiders were immediately capable of normal activity.