Methods of trail formation and organization of group foraging by the ants Formica obscuriventris Mayr, Myrmica americana Weber, and Crematogaster lineolata (Say) were studied under laboratory conditions. Each species was able to organize group travel to a persistent food source. M. americana and C. lineolata achieved this by using trail pheromones, the former species using these pheromones only to establish the trail and the latter using them in all stages of foraging. F. obscuriventris apparently did not use trail pheromones and each individual learned the route to the food independently.

The western tent caterpillar, Malacosoma californicum pluviale (Dyar) was treated externally with farnesyl methyl ether and the crude ether extracts of two forest trees, Western Red Cedar (Thuja plicata) and Douglas-Fir (Pseudotsuga menziesii). Within 24 hr of the intervening molts, late fourth- and early fifth-instar larvae weighing 178 mg received 55 μg, and late fifth-instar larvae and new pupae weighing 450 mg received 140 μg in 0.6 μl of acetone. Controls received only acetone.Treated groups suffered increased mortality due to structural abnormalities, molting difficulties, and increased infection with polyhedral virus and microsporidia. Many surviving adults also were structurally abnormal, and the proportion of females depositing normal egg masses was reduced. The progeny were less viable than those of the controls. Reductions in the viability of progeny were only slightly affected by time of treatment, but egg-laying behavior was more affected by later than by earlier treatments.All materials produced examples of juvenility, but many of the abnormal individuals produced by cedar treatment died early in the pupal stage, whereas those induced by the other treatments lived longer. In most instances, samples were too small to indicate statistical superiority of any one material but, as received, the cedar extract seemed more potent than the fir. Farnesyl methyl ether had the greatest influence on reproductive capacity.

DDT and DDD emulsifiable formulations were tested against aquatic invertebrates in small plots in rapids in the St. Lawrence River. Pollution was minimal; less than 0.0044% of the river discharge was treated in each rest.The weakest dosage of DDD, 0.8 p.p.m.-minutes, disabled many Trichoptera and Diptera; the strongest, 12.0 p.p.m.-minutes, did not eliminate any one Order of insects except perhaps Plecoptera. A dosage of 6.0 p.p.m.-minutes was selected for tests on a larger scale against shadfly larvae (mainly Trichoptera). Net-spinning Trichoptera were more sensitive than case-bearers. Of the non-insect organisms, amphipods were relatively sensitive but their populations were rapidly restored by immigration. Oligochaetes and molluscs were least affected.The use of small plots in a large river required special equipment and techniques: a larvicide dispenser (to be described separately), the use of concentrated milk as a dye to aid in the survey of plot boundaries, the transfer of disabled organisms to fresh water to compare recovery rates, and a formula combining data from samples of both disabled and surviving organisms to estimate per cent kill.

Larvae of Coleomegilla maculata lengi Timberlake and Leptinotarsa decemlineata (Say) were unable to moult and died after ingesting colloidal silica with their food. Field trials showed that dry silica can be used to reduce populations of L. decemlineata on potato.

Dilute solutions of several basic dyes, especially Crystal Violet and Malachite Green, effectively marked cocoons of Neodiprion sertifer (Geoff.). In field experiments, 0.25% Crystal Violet applied to soil at 1.0 gallon per square foot of surface area dyed most N. sertifer cocoons recognizably and was not removed by natural leaching or by the water used in extracting cocoons from the soil. Cocoons spun later in treated soil became contaminated but could be recognized by the distribution of dye on detritus adhering to the surface. Dyeing permitted direct measurement of the density of current generation cocoons in late August, when they were visually indistinguishable from old ones.

The following new taxa are described: Demobotys n. gen., type-species Pyrausta pervulgalis Hampson, Japan; D. pervulgalis exigua n. subsp., Kiangsu Prov., China; D. p. hunana n. subsp., Hunan Prov., China; D. monoceralis, Yuennan Prov., China; Anamalaia n. gen., type-species A. nathani n. sp., South India; Coclebotys n. gen., type-species Botys coclesalis Walker, Borneo, Japan, China, et al.; Yezobotys n. gen., type-species Y. ainualis n. sp., Hokkaido.

The reactions of resistant and susceptible Abies grandis to attacks by Scolytus ventralis are described. Resistant reactions were characterized by the production of secondary resin in the cells of the phloem parenchyma and the formation of callus tissue and traumatic resin cavities at the cambium–sapwood interface. S. ventralis exhibited varying degrees of gallery establishment on resistant hosts. Some individuals were repelled by phloem resinosis before reaching the vascular cambium while others were able to construct galleries of varying length before they were repelled by resin flow from the phloem and traumatic cavities. The degree of gallery establishment appeared to be inversely associated with the rapidity of the host’s response. Necrotic resinous lesions developed around the attack and extended vertically to various distances from the attack. Callus tissue, produced at the margins of this lesion, eventually grew over and healed the wound. Vulnerable grand firs were characterized by the lack of resinosis in the phloem parenchyma, and the absence of extensive callus production and traumatic cavity formation.

Orchex-796 oil and Volck Supreme oil at 2.5 gal per acre gave equal commercial control of adults and nymphs of the pear psylla, Psylla pyricola Foerster, on Anjou pears. Control was better at 5 gal per acre but at this rate, both oils caused sporting and marginal burn on leaves and russet spots on the fruit of Anjou pears. The 2.5-gal rate caused slight leaf spotting, but no fruit injury.This indicates that the recommended rate of 6 gal of oil per acre for Bartlett pears cannot be used on the Anjou variety, and raises the question whether this high rate is necessary for pear psylla control.

Cattle grubs, first-instar larvae of Hypoderma bovis (L.), were removed from nine slaughtered heifers. Two of these heifers had previously been treated with coumaphos, three with Ruelene, and two with trichlorfon. The remaining two heifers were not treated with insecticides and served as sources of control grubs. The grubs, after removal from the hosts and fixation in formalin, were incubated with one of the two cholinesterase substrates, acetylthiocholine iodide or 5-bromoindoxyl acetate. Cholinesterase was completely inhibited in the central nervous systems of the grubs whose hosts were treated with Ruelene. This inhibition was also virtually complete in grubs from heifers treated with trichlorfon and was usually complete in those from the heifers treated with coumaphos. This is presented as histochemical evidence that the three systemic insecticides inhibit the cholinergic enzymes in the grubs, thus causing them to die while still in the body of the host.

Virgin females of Melanoplus sanguinipes (Fabricius) crowded in cages laid normal egg pods whereas solitary ones did not. An average of 8.3 pods per female were laid at a rate of 0.12 pod per female-day. This is less than those laid by fertilized females, and the difference seems to be in the rate of mobilization of materials for the eggs; 56.5% of the eggs showed no development. The remainder developed to varying stages and 5.6% hatched. Diploid, haploid, and subdiploid chromosome numbers were found in parthenogenetic embryonic tissue.

Regression coefficients derived from the Nicholson–Bailey parasite mode) by Hassell and Huffaker (1969) are interpreted, and their conclusions about the biological significance of changes in slope are shown to be invalid. It is demonstrated that the term "delayed density-dependence" has no functional significance because it includes density responses that range from inverse to direct, depending upon the particular theoretical model that is selected for simulation exercises. In natural populations of a number of forest insects, the net response of parasitism to host density is direct, not inverse.

Descriptions and illustrations are given of three microlepidopterous larvae in Baltic amber. Two, one of which appears to be in first instar, are thought to be in Plutellidae and the third in Oecophoridae.

Morphological and histological details of the sex pheromone glands of male Vitula edmandsae (Packard) are reported. Several hypotheses concerning the functions of these glands are discussed.

The most suitable temperature for larval development of Aedes flavescens was found to be 20 °C. At this temperature 74% of the larvae pupated in 20 days. At 15 °C the developmental period was 42 days with a survival rate of 54%. At 25 °C the developmental period was 22 days but the survival rate dropped to 7%. At 10 °C the developmental period was 80 days with a survival rate of 6%. At 5 °C and 30 °C mortality was 100% in the first instar stage. Adult males emerged from the pupae in three days at 25 °C, two days earlier than the females.

Twenty-two species of insect parasites of Fenusa pusilla (Lepeletier) are listed. Fifteen of these species were reared in the present study from F. pusilla in Quebec, 1 on eggs and 14 on larvae; 4 of them act as both primary and secondary parasites. Of the 15, only 1 has previously been reported as a parasite of F. pusilla. Host–parasite relationship and the degree of parasitism are given for the 15 species reared in Quebec.Thirteen species of predators are listed. Of these, 9, three birds and six insects, were observed feeding on F. pusilla larvae during this study.

Data presented demonstrate that induction of pupal diapause in the cabbage maggot, Hylemya brassicae (Bouché), involves a relationship between photoperiodic, temperature, and light intensity conditions provided for the flies, eggs, and larvae. Generally, a short daylength of 12 hours for the flies induces pupal diapause, whereas a 16-hour photoperiod dictates continuous development without diapause. However, the expected response can he partially or almost completely reversed depending upon, conditions of photoperiod and temperature provided for eggs and larvae. Decreasing temperatures combined with low light intensities and short photoperiods for flies and larvae cause almost all pupae to enter diapause, and high temperatures tend to offset the influence of a short daylength or a downward trend in photoperiodic exposures provided for the flies and larvae. Diapause development proceeds to completion at a wide range of temperatures but high levels at certain times result in high mortality. Growth development following the completion of diapause development is inhibited by temperatures above 22 °C, whereas the final or adult developmental stage continues to completion at an increasing rate with increasing temperatures.

The larvae of 11 species of the genus Stenoporpia (Geometridae: Lepidoptera) from Arizona are described, figured, and keyed. On the basis of the known larvae, Stenoporpia can be divided into four very distinct species-groups, one feeding on species of oak, and the other three on conifers. Temporal displacement was found in four species of Stenoporpia feeding on ponderosa pine at the Fort Valley Experimental Forest near Flagstaff, Ariz. The sensory papillae of the maxillary palpi are investigated as a taxonomic character. A list of all of the known foodplants of the species of the genus is given.

The following new species and subspecies of Dioryctria Zeller are described: D. pentictonella, related to D. baumhoferi Heinrich, from buds of young Pinns ponderosa in the interior region of British Columbia; D. pentictonella vancouverella from buds of P. contorta and of several introduced species of Pinus in coastal British Columbia; D. okanaganella, related to D. ponderosae Dyar, from old pitch nodules and blister rust on Pinus ponderosa in the interior of British Columbia and in Washington.

Newly hatched Oryzaephilus surinamensis (L.) were reared on a chemically-defined diet at 32 ± 2 °C and 75 ± 5% relative humidity. Addition of serine to the diet containing glycine was not beneficial to the insect and became harmful at a concentration greater than 10.0 mg/g. Serine was able to replace glycine almost completely in the glycine-free diet for this insect. The results suggest that glycine, but not alanine or threonine, is the precursor for serine biosynthesis in O. surinamensis. They also suggest that serine and glycine are not completely interconvertible by this organism.

Some 35 species (mostly Neotropical, 22 new) of acalypterate flies representing 17 genera (3 new) in six families, as follows, are treated: Family Cypselosomatidae. One species from Nepal, Cypselosoma gephyrae Hendel (?), is discussed.Family Pseudopomyzidae. The classification of the family is reviewed, and a key to the world genera is provided. The genus Latheticomyia Wheeler is placed here for the first time, and two new species, L. longiterebra (Peru) and L. rotundicornis (Mexico), are described. Two new genera, Pseudopomyzella and Rhinopomyzella, are erected for three new species, P. flava (Peru), R. albimana (Brazil), and R. nigrimana (Brazil).Family Periscelidae. The genus Periscelis Loew is recorded from Mexico and Peru. Neoscutops peruvianus and Scutops striatus, both from Peru, are described as new.Family Aulacigastridae. The classification of the family is reviewed and a key to the world genera is provided. Schizochroa plesiomorphica (Peru), S. minuta (Ecuador), S. ecuadoriensis (Ecuador), Cyamops neotropicus (Peru), C. australicus (Queensland), and Planinasus venezuelensis (Venezuela) are described as new.Family Odiniidae. The classification of the family is reviewed and a key to the subfamilies and the world genera is provided. Two new species of Schildomyia Malloch, S. peruviana (Peru) and S. trinidadensis, are described. A new genus, Shewellia, is erected for the species S. agromyzina (Peru).Family Heleomyzidae. One new species of Cephodapedon Malloch, C. nigriventer (Chile), is described. The genera Mayomyia Malloch and Cinderella Steyskal are reviewed and placed in this family for the first time. Four species of Cinderella, C. macalpinei (Ecuador), C. pollinosa (Chile), C. hirsuta (Chile), and C. steyskali are described as new.The paper is accompanied by 72 illustrations.