Podisus modestus (Dallas) has one generation per year in the boreal forest of Quebec. Adults hibernate in the litter and soil from mid-autumn to late spring. Overwintered adults were found in the field until the latter part of August. Adults mated shortly after emergence from hibernation. Females mated an average of three times during the summer; the maintenance of a supply of highly fertile eggs apparently required this periodic mating. Young adults, which emerge from August to October, neither mated nor laid eggs before hibernation.The preoviposition period after first mating was 10 to 19 days. Females laid an average of 7.9 egg masses (average of 16.7 eggs per mass) at intervals of 1 to 25 days on jack pine, and on Kalmia and Vaccinium spp.Eighty per cent of the eggs hatched successfully after a mean incubation period of 15.3 days; 12% did not develop while 8% developed and were destroyed, during hatching, by other first-instar nymphs in the brood. Maturing nymphs spent an average of 7.7, 7.7, 7.8, 11.9, and 23.8 days in each of the five respective stadia, and required 59 days from hatching to adult emergence. A logistic curve describes the relationship between developmental time and temperature. First-instar nymphs required no animal food, but during each of the last four instars animal food was required for maturation. The hunting and feeding behavior, food consumption, abundance and mortality of P. modestus are also described.

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.

The effect of temperature on the rate of development of Anax junius Drury was studied. Monthly larval samples were carried out for 2 years and laboratory experiments were conducted at constant temperatures. Field studies, at a eutrophic pond near Toronto, showed that in Canada populations of A. junius are not only maintained by migrants each year but also by residents. Two distinct populations were found, a summer (non-resident) population which developed from oviposition to emergence in approximately 3 months, from June to September, and an overwintering (resident) population which overwintered as half-grown larvae and developed in approximately 11 months from mid-July of one calendar year to the end of June of the next year. The former population was larger and comprised approximately 48% males and the latter was smaller and comprised approximately 41% males. A threshold temperature of development of 8.7° ± 0.1 °C was determined in the laboratory for the development of final-instar larvae of the summer population. The rate of development of final-instar larvae, reared at constant temperature, was similar to that of the entire summer aquatic stages which developed in fluctuating temperature. An average of 1332 degree-days ± 1% was required for development from the onset of oviposition to the onset of emergence of the summer population; whereas 20.5% more degree-days were required for the development of the overwintering population, employing the threshold temperature of 8.7 °C as determined for the summer population.It is recommended that correlation between degree-day totals and duration of larval development be used in further studies as a means for understanding the migration pattern and also the climatic limit of distribution for A. junius.

Zamischus elongatus n. sp. and male Z. braziliensis Ashmead from Brazil are described and illustrated.

Females of Muscidifurax zaraptor K. & L. oviposit on unparasitized housefly (Musca domestica L.) pupae in preference to those attacked by M. zaraptor, Nasonia vitripennis (Walk.), or Spalangia cameroni Perk. (Hymenoptera: Pteromalidae). The discrimination against parasitized houseflies is greatest in the case of those attacked by M. zaraptor and least for those parasitized by S. cameroni. Discrimination is based on differences between unparasitized and parasitized pupae that the female parasites detect after they pierce the pupae with the ovipositor. Death of parasitized hosts, or a change resulting directly therefrom, is not responsible for the differences. The fact that hosts pierced at or near the original drilling site are more likely to be rejected than those attacked elsewhere supports the hypothesis that a ’venom’ injected by the female parasites during oviposition diffuses throughout the host and is responsible for oviposition restraint.

Several genetic insect control methods are currently available, but they are practicable only when population densities are low.In this paper we describe ways of increasing the frequencies of dominant conditional lethal genes in populations. The proposed methods should be particularly valuable for the eradication of major agricultural pests controlled at present by frequent applications of insecticide.Eradication of boll weevil populations could be accomplished by the release of relatively small numbers of artificially reared insects. The number required can be less than it is for other proposed methods by a factor of 100 or more¡¡

The adult densities of Hippodamia tredecimpunctata tibialis (Say), Coccinella novemnotata Hbst., and Coccinella transversoguttata richardsoni Brown, on corn fluctuated in July and August and reached their maxima at pollination, whereas the density of Coleomegilla maculata lengi Timberlake fluctuated much less. C. maculata, H. tredecimpunctata, and C. transversoguttata were more numerous on plants with a liver diet applied to their foliage than on untreated plants. H. tredecimpunctata, C. novemnotata, and C. transversoguttata were less numerous on plants that had their tassels removed and produced no pollen than on intact plants. C. maculata, H. tredecimpunctata, and C. transversoguttata were more numerous on plants exposed to the maximum amount of sunshine than on plants that were shaded for part of each day. H. tredecimpunctata was more numerous on plants situated at low elevation than at high elevation, whereas C. transversoguttata was more numerous at high than at low elevation. C. maculata and H. tredecimpunctata were more numerous on plants near the middle of a corn field than on plants at the perimeter of a field adjacent to buckwheat, whereas C. novemnotata and C. transversoguttata were most numerous on plants near the perimeter. Two-species associations of C. maculata and H. tredecimpunctata, C. novemnotata and H. tredecimpunctata, C. novemnotata and C. transversoguttata, and C. novemnotata and H. tredecimpunctata occurred on individual plants. Plant density and time of planting affected coccinellid density. Adult density was greatest at a plant density of 3.2 plants per square metre and adults were more numerous on early than on late planted corn.

Loblolly pine trees struck by lightning offer a favorable attack and brood environment for the southern pine and Ips beetles. In central Louisiana lightning strikes reduced oleoresin exudation pressure, oleoresin flow, and relative water content of inner-bark tissue and resulted in a decrease in sucrose and an increase in reducing-sugar content of inner bark. Interspecific competition was much greater in struck trees than nonstruck trees. Among struck trees, those with highest carbohydrate levels produced the most numerous broods of the southern pine beetle.

The number of valid forms of Acanthopsylla Jordan and Rothschild in Australia now stands at 12 including, as new species, dunneti and incerta, and as new subspecies, rothschildi multidentata, scintilla rectangulata, and scintilla tasmanica. Descriptions are provided for these and notes and illustrations on some of the others. A. rothschildi victoriana is reduced to synonymy with A. r. rothschildi.

In 1968 and 1969 soil samples were collected and bioassayed from 116 fields of crucifers from 14 counties in southern Ontario. Residues of T. ni viruses (nuclear-polyhedrosis (NPV) and granulosis (GV)) were found in soil from 12 counties, being detected in 68 and 45% of soil samples in the respective years. P. rapae granulosis virus (GV) occurred in soil from 7 counties, being found in 18 and 19% of samples. T. ni NPV was more common than T. ni GV. The concentration of viruses of both host species in soil was influenced by density of the host population, crop rotation, soil pH, and month of sampling.

A biotype of the pea aphid was characterized. Two host plants were used: broad bean and pea. It was found that the weight during the development, the survival of adults and their fecundity were better on broad bean as compared to pea.

The distributions of attack, gallery length, eggs, and first instar larvae of an endemic population of the western pine beetle in ponderosa pine are described.

Mean gallery length (GL) and larval (L) densities of mature populations are significantly correlated with attack (A) density. The associations are adequately described by the simple linear regressions

The ratios E/GL and L/GL are stable over a wide range of gallery length densities and consequently egg-gallery length and larval-gallery length correlations are highly significant. The regression equations are

All four equations predict values within 10% of observed values.An 88 cm2 sampling unit is satisfactory for sampling either egg or first instar larval populations. Taking four paired sampling units, evenly spaced along the infested bole, from each of four trees per generation, provided a sampling precision of 15%. Increasing the number of paired units to 10 and the number of trees sampled per generation to 9 improved the precision to 10%. If the trees are sampled before oviposition is complete, the number of sampled trees per generation should be increased by 1 for each level of precision.

The high density of the field crickets Gryllus pennsylvanicus (Burmeister) and Nemobius fasciatus (DeGeer) under test trees in an unsprayed orchard, and the high mortality of apple-maggot pupae, Rhagoletis pomonella (Walsh), in test lots at the same time of year, suggested that crickets may have preyed heavily on the pupae and thus have constituted important mortality factors. Laboratory observations showed that crickets can detect, disinter, and consume apple-maggot pupae in simulated natural surroundings.

Two new species of Naphius Stål are described, and a key to the known species is given.

The tracheal system of all three larval instars of Hypoderma is metapneustic. The arrangement generally resembles that in the Cyclorrhapha except for reduction of the dorsal anastomoses, lateral, longitudinal, and spiracular tracheae and the apparent absence of ventral cervical tracheae. The transverse connectives consist mainly of secondary and tertiary branches, but the dorsal anastomoses have only secondary branches, if any. The transverse connectives extend to the ventral and lateral somatic musculature and to the alimentary canal. The dorsal anastomoses supply mainly the heart and dorsal somatic musculature.

A new genus and species of Euderinae, Aoridus campbelli n. gen., n. sp., related to Bellerus Walker (Eulophidae: Chalcidoidea) and collected from Colombia, South America, is described and illustrated.

The following behavioral patterns of three chalcidoid parasites, Monodontomerus obscurus, Pteromalus venustus, and Melittobia chalybii, were compared in the laboratory: feeding by adults, precopulatory routines, copulating, anesthetizing the host, ovipositing, mobility of the larvae, cannibalism among larvae, overwintering, diapause, life cycle, and the ability of a host to support a parasite.

Normal matings of Choristoneura fumiferana (Clem.) resulted in the transfer of single, persistent spermatophores. The mean duration of copulation was 4 hours with a range from 21/2 to 81/2 hours. All the first matings of males were fertile and the spermatophores were large, while an increasing proportion of the subsequent matings were infertile and the spermatophores became progressively smaller. Only fertilized females laid normal numbers of eggs. There was no evidence to show that insemination can be accomplished without the transfer of a spermatophore. However, the presence of a spermatophore in the bursa of the female was not always indicative of successful insemination.Males mated only once within a 24-hour period; they were least responsive to females just after emergence (< 0.5 day old) and most responsive when 2 to 4 days old. Females mated most readily when < 0.5 day old and became progressively less attractive or less receptive with age. Mated females were not as attractive as unmated females.

The occurrence and abundance of larvae of Chironomus tentans Fabricius in saline lakes in central British Columbia were studied with respect to: (1) physico-chemical properties of the lakes, (2) physical composition of the bottom muds, (3) food availability, and (4) co-occurrence with other species of chironomids. The study was done to determine the ranges of environmental conditions to which the larvae are adapted and to identify specific environmental factors which might be of particular significance to natural selection. Abundance was significantly correlated with the amount of food available; the numbers of individuals of other Chironomus present; the percentage of mud particles in the 0.59–0.83 mm range; pH; conductivity; and the concentrations of potassium, magnesium, chloride, sulfate, and dissolved oxygen. In general, occurrence was affected by the same factors which affect abundance. Additionally, larvae did not occur when hydrogen sulfide was greater than 0.3 p.p.m. The ecological data are particularly relevant since they provide a basis for studying the evolutionary significance of ecological adaptation in C. tentans.