The Mexican and Central American species of the Genus Isomira Mulsant (Coleoptera: Alleculidae) are revised. Ten species and four subspecies are treated, of which six species and all the subspecies are described as new. New species are: Isomira championi, I. howdeni, I. rotundata, I. mexicanus, I. acuta, and I. alticola. New subspecies are: Isomira howdeni hidalgoensis, I. subaenea soror, I. s. punctata, and I. s. guatemalensis. A key is presented for the determination of the taxa.

Larvae of the larch sawfly, Pristiphora erichsonii (Htg.), were fed foliage of tamarack, Larix laricina (Du Roi) K. Koch, treated with solutions of the vital dyes, Nile blue sulphate, rhodamine B, and coriphosphine O, to determine their suitability as markers. Coriphosphine O was highly toxic at the concentrations administered but successful tagging was obtained with the other two dyes. Optimal dye retention and survival were obtained when larvae were fed for 3 days early in the last stadium using Nile blue sulphate and throughout the last stadium using rhodamine B.

Both dyes persisted throughout development and were incorporated in the cocoons and the oviposited eggs. They could be readily seen in all stages except for the cocoons and for eggs that contained rhodamine B. The dyes could be detected in cocoons by treating them with cold KOH followed by ethanol. The presence of rhodamine B in the eggs could be ascertained by its yellow fluorescence in ultraviolet.

The dyes incorporated in the cocoons are relatively stable and laboratory tests indicate they probably can withstand weathering under normal field conditions over a 1-year period.

The use of these dyes for internal marking should prove useful in studying adult dispersal and flight range and as a technique for use in population studies of the larch sawfly.

Studies were conducted on the reactions of small mammals to the vital dyes Rhodamine B and Nile Blue. The dyes are currently in use as biological tracers for the larch sawfly. Two species of voles and two of four individual shrews reacted indiscriminately to dyed and undyed material: the reactions of the two remaining shrews varied. It was concluded that the behavior of small mammals would not affect seriously the results of field experiments using insects labeled with these dyes.

The relationship between nutrition of the host tree, Abies amabilis (Dougl.) Forbes, as influenced by nitrogen fertilizers, and the growth of populations of the balsam woolly aphid, Adelges piceae (Ratz.), was investigated. Sixty trees, growing in a greenhouse in two soil types, a nutrient-deficient mineral soil and an enriched humic soil, were infested with woolly aphid larvae. Subsequently, groups of 10 trees received foliar treatments of various concentrations of ammonium nitrate and urea. The following year, 32 young trees in Seymour Valley, B.C., were studied to determine the effect of fertilization of uninfested trees on establishment of aphid larvae.

In the greenhouse, foliar sprays of 1% ammonium nitrate solution resulted in a 23% decrease in population in 10 weeks, as contrasted with a 31% increase in the control population. In the field, larval establishment was 31% to 37% lower on the ammonium nitrate-treated trees than on the control trees. Inasmuch as there was no evidence of increased mortality of aphids in situ, we infer that the fertilizer acts primarily by inhibiting initial settling of larvae on the host trees.

A complete list of the 29 species of fleas known from New Brunswick is presented, including several species not previously recorded and one previously undescribed species. New records are listed, with host data, for most of the species.

The habits of the San José scale, Aspidiotus perniciosus Comstock, and the European fruit scale, A. ostreaeformis Curtis, on harvested apples in British Columbia are discussed under the following topics: stages found on apples; distribution and mortality on apples; influence on size, odor, and skin of apples; discoloration of fruit; and appearance of scales on apples. Outstanding characteristics of the San José scale are: all stages occur on the fruit; crawlers settle primarily in the stem end of Newtown and Winesap apples, equally in the stem and calyx ends of Rome Beauty, and predominantly in the calyx end of Delicious; the scale survives longer in the stem end than in the calyx end of stored Newtown, Winesap, and Delicious apples; all scales eventually die in storage; and infestations decrease the size of apples, adversely affect color and maturity, impart a moldy odor to the fruit, and mark the skin of all varieties by causing red spots around the scales. Comparable habits of the European fruit scale are: males and females do not occur on the fruit; more crawlers settle in the stem end of Newtown, McIntosh, and Hyslop crab apples than in the calyx end but the reverse distribution occurs on Rome Beauty; the scale survives longer in the calyx end of all varieties; all scales do not die on apples placed in storage; infestations apparently do not affect size, color, maturity, and odor of fruit; and feeding of the scale seldom marks the skin of Newtown apples but it does cause purplish-red spots around the scales of all other varieties of apples.

The responses of adult Aedes aegypti L. to real and simulated linear movement at inanimate target areas were investigated. The results suggested that warmth and humidity together were of greatest influence in attracting flying A. aegypti, but a dark object at ambient conditions in the vicinity of a warm humid white target received almost equal attention from the flying mosquitoes. Incident illumination as low as 100 lux markedly reduced the attractiveness of an otherwise attractive surface. Movement had a consistently small but positive attraction, though the effects of this might be obscured by local air turbulence due to the motion.

The world genera (15 in all) of Drosophilidae with bare (i.e., non-plumose) aristae are brought together, and a key is provided for identifying them. Notes are provided in the key on type species, synonymy, numbers and distributions of included species, and pertinent literature. The genus Paracacoxenus Hardy is revised to include not only its one Nearctic species, guttatus Hardy and Wheeler, but also three European species that were originally assigned to Cacoxenus Loew, i.e., argyreator (Frey), exiguus (Duda), and inquilinus (Hendel). Lectotypes are designated for Cacoxenus punctatus Duda (a junior synonym of Gitonides perspicax Knab), for Gitona vlasovi Duda, for Paracacoxenus argyreator (Frey), and for P. exiguus (Duda). The paper includes 30 figures.

Camptomyia pseudotsugae, a new species of midge in Douglas-fir cones from Washington and British Columbia, is described. Notes on its life history and habits in relation to those of its cohabitant Contarinia washingtonensis Johnson are included.

Larvae of the winter moth, Operophtera brumata (L.), and the Bruce spanworm, O. bruceata (Hulst), differ in the number of instars, in habits, and slightly in morphology. Populations may be distinguished readily by these criteria, but individual larvae sometimes give difficulty. The form of the pupal cremaster is distinctly different.

Different stages of the European red mite, Panonychus ulmi (Koch), were immersed in water for periods up to 48 hours. Mortality of eggs was negligible; of active stages it was low but appreciable. Immersion in water inhibited egg hatching, feeding, moulting, and oviposition. It was concluded that if the mite responds similarly under orchard conditions, frequent or prolonged wet periods would delay the buildup of a mite infestation.

Hypothyce mixta, a new genus and species from eastern Texas is described and compared with the related genera Thyce LeConte, Plectrodes Horn, Dinacoma Casey, and Hypotrichia LeConte. A key to the genera of Melolonthini of America north of Mexico is included and the genus Hypotrichia is transferred from the Liparetrini to the Melolonthini.

Oviposition of the predacious mites Phytoseiulus persimilis and Typhlodromus fallacis began 2 days after mating, reached a peak in 1 week, and then declined irregularly. The rates of oviposition were higher, and the oviposition period shorter at 26° than at 20°C. P. persimilis laid 47% more eggs than T. fallacis. The generation time for both species was very dependent on temperature. Minimum values of 112 hours for P. persimilis and 127 hours for T. fallacis were obtained at 28°.

Calculations of potential predator populations from the generation time, age-specific fecundity, and proportion of females were made on a daily basis for successive generations. The potential number of living females derived from one mated pair increased logarithmically after a few cycles representing new generations. The rate of increase of P. persimilis populations was 26% higher than that of T. fallacis, and in both species the rate at 26° was about double the rate at 20°.

A sample of larvae submitted to us for identification on 22 November 1967 by Dr. C. Hutton, Director, Diagnostic Laboratories, Janeway Child Health Centre, St. John's, was determined as Anisopus fenestralis (Scopol.) by Dr. H. J. Teskey, Ottawa.