The pulsatile organ, or "accessory heart," in the tibia of Triatoma consists of a membrane which divides the femur and tibia into a series of sinuses, a pulsatile muscle which propels the haemolymph through the sinuses, and a valvular membrane, which imposes unidirectional flow on the system. A possible innervation of the muscle is described, and simple experiments involving nerve stimulation demonstrate that the pulsatile muscle is under nervous control. Using partially isolated preparations of the pulsatile organ, it has been shown that the organ responds to dopamine and serotonin, but fails to respond to acetylcholine. The pulsatile muscle therefore resembles visceral muscle rather than skeletal muscle.

The roles of adult activity patterns and sex pheromones were investigated in the sexual isolation of Choristoneura fumiferana and C. pinus, species which hybridize in cages but not in the field. Female C. fumiferana started calling (extruding the sex pheromone gland) earlier (50% of the females started calling by sunset) than female C. pinus (50% by 11/2 hours after sunset). Male C. fumiferana were also attracted to traps by the females earlier, although the times of the peak catches were approximately the same in both species. Males, both in the laboratory and the field, responded only to the sex pheromone of their own species. It is therefore concluded that while C. pinus adults normally appear about 2 weeks later than those of C. fumiferana, which reduces the possibility of hybridization, when the adults do overlap, the ultimate barrier is the specificity of the sex pheromones.

The following new pyraustine taxa are described: Parbattia serrata n. sp., Sikkim and northern India; P. arisana n. sp., Taiwan; Epiparbattia gloriosalis whalleyi n. subsp., Assam.

Opius melleus Gah. and O. lectus Gah. were the only parasites of Rhagoletis pomonella (Walsh) found in southern Ontario during a 4-year survey. The parasites were found only in the Niagara Region on the slope of the Niagara Escarpment and between it and Lake Ontario. The population of parasites was low though they appeared to be well adapted to attack R. pomonella. They were found in, or adjoining, unsprayed sites where there was shrubby growth under the trees infested by R. pomonella.

The currently recognized Ephemerella species are included in 13 subgenera. New subgenera are Cincticostella and Acerella. Ephemerella levanidovi Tshernova is transferred to Cincticostella n. subg., thus it contains six species, E. nigra Ueno n. comb., E. castanea n. sp., E. delicata n. sp., E. imanishii n. sp., E. insolta n. sp., and E. levanidovae Tshernova n. comb. The subgenus Acerella n. subg. includes four species, E. longicaudata Ueno n. comb., E. commodema n. sp., E. perculta n. sp., and E. undatella n. sp., Ephemerella yoshinoensis Gose is transferred to the subgenus Drunella and four undescribed and unnamed species, E. kohnoi n. sp., E. aculea n. sp., E. hifurcata n. sp., and E. borakensis n. sp., are placed in Drunella. Three undescribed species, E. denticula n. sp., E. keijoensis n. sp., and E. maxima n. sp., are included in the subgenus Ephemerella s. s.

Between 1961 and 1965, 15 species of predators from India and Pakistan were introduced into North Carolina for use in biological control experiments on the balsam woolly aphid. Recovery studies of these species have been made, but to date there is no evidence that any has become established. Lack of establishment is attributed largely to important differences in climate between the old and new environment and also to poor prey acceptance on the part of predator larvae and ovipositing adults.

Intensive studies on the damage and losses of flue-cured tobacco caused by the dark-sided cutworm, Euxoa messoria (Harris), were carried out in the field at Delhi, Ont., during 1967 and 1968. A new method for estimating the accurate tobacco crop losses is illustrated. Assessment of damage of the tobacco plant and the population density in relation to the yield are described. The yield was significantly related, negatively, to the dark-sided cutworm density, and was reduced in the cutworm-damaged blocks in comparison with the yield in the undamaged check blocks. Assessment of average losses caused by the species was 17% of marketable tobacco, which, based on the average current prices, would amount to 200 dollars per acre or approximately 25 million dollars over the country as a whole every year.

The genus Euderus Haliday in America north of Mexico consists of five subgenera, Secodelloidea Girault, Euderus Haliday, Euderoides n. subgen., Neoeuderus n. subgen., and Leipocrossus n. subgen. and 25 species; 13 species are described as new and are as follows: Euderus (Secodelloidea) canadensis, E. (Euderoides) purpureus, E. (Neoeuderus) viridilineatus, E. (Neoeuderus) magnificus, E. (Leipocrossus) californicus, E. (Euderus) solidaginis, E. (Euderus) vockerothi, E. (Euderus) chillcotti, E. (Euderus) masoni, E. (Euderus) fuscedinellae, E. (Euderus) pecki, E. (Euderus) glaucus, and E. (Euderus) alaskensis. Species groups of albitarsis and solidaginis form two natural groupings within the genus Euderus s. str. Keys to subgenera and species, distribution, and host records are included.

Abatement programs for nuisance species of Trichoptera at Fort Erie, Ont., and Montreal, Que., are compared and attempts are made to determine why the former was successful throughout 16 consecutive years but failed in the 17th, whereas the Montreal project was not successful in its initial test. In both, DDT was used as a residual insecticide in the resting places of the adults. It is suggested that DDD (TDE) be considered as a substitute for DDT if a relatively waterproof, residual insecticide is required for this specific purpose.

This paper is the first of two concerning overwintering of shallow-pond Chironomidae in regions with cold winters, and deals with winter habitat conditions as a background to a later report on chironomid biology.

Some observations on winter temperatures and factors affecting them, especially in terms of whether freezing occurs, are given for shallow ponds near Ottawa, Ont. (45° N.), where mean air temperatures are about −10 °C for the 3 months of midwinter. Ice thickness was inversely proportional to the depth of overlying snow. The high snow cover on a sheltered pond prevented thick ice from forming and the bottom temperature at a depth of 25 cm remained near +2 °C throughout the winter. Up to 40 cm ice occurred on an exposed pond where snow was largely blown away. Maximum ice thickness was not reached until mid-January. The mud surface at a depth of 15 cm froze only on 22 December and at a depth of 25 cm not until 11 January. The minimum temperature near the margin (at a depth of 15 cm) at the mud surface was −2.6 °C, and 5 cm into the mud was −1.7 °C. In 1969 abnormal rainfall in November increased the pond level by over 30 cm just prior to freezing. Of the area subsequently frozen down to the bottom, three-quarters had been dry in the summer. The frozen portion represented 61% of the total pond area.

The winter features of shallow pond environments as winter habitats in north temperate regions and in the arctic are reviewed. In north temperate regions, there is great variability in terms of freezing, produced by a complex of interactions between local topography, precipitation, and air temperatures. The minimum in the least favoured areas, maintained for a relatively short period, is only a few degrees Centigrade below freezing, and often considerable areas remain unfrozen especially in sheltered habitats. Part of most summer-permanent habitats remains unfrozen except in unusually severe years. Winter conditions are ameliorated beneath ice and snow insulation by heat stored in the earth below; solar radiation is probably of little importance. Winter stagnation with exhaustion of oxygen may occur in unfrozen areas beneath ice cover, together with increase of concentration of solutes. In the arctic, ponds up to about 1½ to 2 m deep are frozen to the bottom. Minima in the bottom mud may reach −20 °C or −30 °C for several months depending on latitude and on local topography.

Internal cone temperatures recorded in the mornings and in the afternoons demonstrated marked differences between sunny and shaded sites. Analysis of variance confirmed differences between treatment as highly significant. High and low cone temperatures coincided with high and low ground temperatures. The average correlation coefficient relating cone and ground temperatures was highly significant, while that for cone temperatures and cone size was non-significant.

Heavy insect mortality occurred in cones exposed to direct solar radiation but mortality remained relatively low in the cones left in the shade. The greatest high-temperature mortality occurred during summer between late June and early August.

The life histories of Nemoura besametsa, Epeorus deceptivus, Epeorus longimanus, and Ephemerella coloradensis are described as "fast seasonal" types and Arcynopteryx aurea, Nemoura cinctipes, Nemoura columbiana, Nemoura oregonensis, Cinygmula ramaleyi, Ephemerella doddsi, and Rhithrogena doddsi as "slow seasonal" types according to Hynes’ (1961) classification. All of the species are univoltine with the exception of N. cinctipes which may be bivoltine. There seems to be a correlation between life cycles and food availability. A means of ecological separation in the four Nemoura species is elucidated. Stream temperature was found to influence growth rates.

Annual cone abundance and insect damage to cones are highly variable in red pine seed-production areas. Cone crop size fluctuates almost unpredictably from year to year, but the number of insect-attacked cones tends to increase annually unless limited by cone abundance. Sixty-six per cent of the variation in cone damage can be associated with variations in cone abundance. This information, coupled with the fact that red pine cone insects are almost entirely dependent on red pine cones for food, implies that crop size is highly important in regulating populations of cone insects. Insects will be most devastating in areas where crop size varies little from year to year.

The seasonal occurrence, habits, and immature stages of Phratora hudsonia Brown are described, and a generic key to forest Chrysomelinae of Ontario is given.

Anti-attractants, defined as substances with little or no intrinsic repellency but with the property of diminishing the attractiveness of a lure, are predicted on spectroscopic grounds and their existence demonstrated in experiments with Ceratitis capitata (Wiedemann), and Dacus cucurbitae (Coquillett).