Examination of the salivary glands and the saliva of the six-spotted leafhopper, Macrosteles fascifrons (Stål), with the transmission electron microscope revealed three kinds of membrane-limited bodies. Typical mycoplasma-like bodies (MLBs) were found in the salivary glands of leafhoppers transmitting aster yellows, but were absent in those never exposed to a disease source. Rickettsia-like bodies (RLBs) and other small bodies named salivary bodies (SBs), apparently associated with the secretion of saliva, were found in both transmitting and nontransmitting leafhoppers. Pronase digested the SBs in 20 min and pepsin in 2 h, but neither enzyme had any effect on MLBs or RLBs.

In Hylemya brassicae (Bouché) little oviposition occurred when access to host plant material was denied. The mustard oil, allyl isothiocyanate (AITC), stimulated the flies into greater activity and attracted them to its source. Sinigrin and four other glucosinolates (mustard oil glucosides) tested induced oviposition. AITC by itself did not induce, oviposition, but in the presence of a glucosinolate, small concentrations of AITC caused an increase in the number of eggs laid. Glucose, sucrose, casein, wheat germ oil, and a mixture of B-vitamins did not influence oviposition at the concentrations tested, but casein hydrolysate inhibited it. The role of glucosinolates and common nutrients in host selection by H. brassicae is discussed.

Leaves of each of six cruciferous plant species investigated contained glucosinolates. There was no correlation between the total glucosinolate concentration of the species (identity of the glucosinolates unknown) and the oviposition response of the adult cabbage maggot, Hylemya brassicae (Bouché). Tests with chemical fractions isolated from rutabaga root tissue indicated that glucosinolates are the major, and perhaps the only, oviposition-inducing substances present in cruciferous plants. It is suggested that oviposition preferences are governed by the presence of some ’key’ glucosinolates and the absence of inhibitory chemicals.

The intensive use of sex pheromone traps in an insecticide-free apple orchard from 1972 to 1974 reduced the codling moth population and level of fruit damage. The sex ratio of bait-trapped adults indicated that the male population was being reduced by the pheromone traps. In commercial orchards pheromone trapping of males suppressed codling moth damage to fruit but the amount of damage was above acceptable economic levels.

Fluorescent powders provided an effective method for marking and monitoring flight activities of adults of Glischrochilus quadrisignatus (Say), a pest of processing tomatoes. Observations and experiments were conducted that would have been impossible with unmarked insects.

Experiments showed that small numbers of beetles located hampers with damaged tomatoes placed 300 m from a release point within less than 2 h. Tomatoes picked and cracked 1, 2, or 3 days prior to release of marked beetles attracted beetles in a ratio of 1:2:3. Approximately 3.5 times as many starved as fed beetles were attracted to damaged tomatoes. Most of the beetles landed on the ground near the hampers and entered via the floor, rather than landing on tomatoes at the top of the hamper.

The significance of the above four findings in relation to control of the insect is (1) beetles are probably attracted to damaged tomatoes from a wide area; (2) tomatoes should be harvested as close as possible to the scheduled time of delivery to the factory; (3) more severe infestations could occur subsequent to periods of inclement weather when beetles, are unable to move to new food sources; and (4) the treatment of hamper floors with insecticides before harvest may assist in control.

Annual population estimates of spruce budworm, Choristoneura fumiferana (Clem.), larvae and the incidence of larval parasitism were monitored in northern New Brunswick following the collapse of the 1949–1959 epidemic in the region. The most common parasitoid among the very sparse hosts was Synetaeris tenuifemur, although it had been rarely found during the epidemic. Larval parasitism sometimes exceeded 50% but it could not be shown as a key factor associated with changing host abundance.

Pseudodiamesa arctica (Mall.), Heterotrissocladius subpilosus (Kieff.), Orthocladius (s.s.) lapponicus Goetgh., Orthocladius (s.s.) sp., Paracladius quadrinodosus Hirv., Trissocladius tricornis n. sp., and Lauterbornia sedna n. sp. develop from egg to pharate adult in Char Lake. The occurrence of the larvae of 7 additional species is apparently adventitious, All stages of the two new species plus the larvae of P. arctica and P. quadrinodosus are described. The males of T. tricornis are dimorphic and L. sedna is parthenogenetic. New distribution records are given for most of the species. The chironomid fauna of Char Lake is compared with that of other arctic lakes.

The three species of Iphitrachelus in America north of Mexico are reviewed. I. canadensis n. sp, is described from Ontario, Quebec, and Newfoundland. A key to all known species is given. The world distribution of Iphitrachelus is discussed.

Gauze covers placed over the entrance of one air intake louver (1.52 m × 1.52 m, ht. 11.85 m, air passage 3055.8 cu.m/min) on the penthouse of the Research Station, from May until December, during a 3-year period, trapped more than 150 aphid species. In addition a considerable amount of intercepted aphid material was identified to genus only. A total of 31,482 specimens were trapped over the period.

Five species, Rhopalosiphum maidis (Fitch), Rhopalosiphum padi (Linnaeus), Mindarus abietinus Koch, Alhis craccae Linnaeus, and Capitophorus eleagni (del Guercio), predominated in all years. In 1967 and 1968 more than 100 specimens each of Pterocallis alnifoliae (Fitch), Tinocallis ulmifolii Monell, Myzocallis occultus Richards, Prociphilus americanus (Walker), Capitophorus hippophaes (Walker), Hayhurstia atriplicis (Linnaeus), Thuleaphis rumexicolens (Patch), and Myzus persicae (Sulzer) were trapped each year.

Once potential development temperatures were reached there was little correlation between mean temperatures and aphid numbers up until frost.

The earliest interception was 6 May; general dispersal was under way by 6 June and continued until late November, despite preceding October frost.

The distribution of attack by Scolytus tsugae (Swaine) between and within trees was evaluated in a small, isolated stand of Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) saplings in northern Idaho. Distribution of attacked trees was determined from a complete inventory of the stand Within-tree distribution of attack was evaluated from sample bolts removed from three levels of each of nine sample trees. The infestation was concentrated (> 50%) in the 5-in. (12.7-cm) (dbh) trees during the 3-year outbreak period, but spread to the next smaller and larger diameter classes during the peak year. Approximately 52% of available host trees in each of the 5- and 7-in. (12.7- and 17.8-cm) diameter classes were killed during the outbreak. The lower and middle thirds of the bole sustained the highest number of attacks per ft2 (930 cm2). There was no significant difference in the percentage of successful attacks per ft2 (930 cm2) between tree level; however, the degree of success tended to increase with height in the tree.

Larvae and pupae of eight species of Tabanidae are described: Chrysops sequax Williston, Hybomitra cincta (Fabricius), H. longiglossa (Philip), H. microcephala (Osten Sacken), H. daeckei (Hine), Tabanus novaescotiae Macquart, T. colon Thunberg, and T. wiedemanni Osten Sacken. A key is provided for identification of nine of the 10 species of Tabanus currently known to possess a stigmatal spine.

Over 95% of feeding balsam woolly aphids occur in crevices on balsam fir branches and the highest density occurs within the 3-year tip of branches. The crevices occur under the bud scales at nodes, the base of each season’s growth, and among staminate flower buds or among and within flower bracts. The abundance and survival of aphids as well as mortality factors vary with the location of the nodes in a branch, the type of branch, and aphid generation. The significant differences show that there are 9 to 13 strata within the 3-year tip of a branch. For ecological studies and measuring population levels, the cluster of aphids within a defined crevice, for example under the bud scale at the base of a cluster of shoots, can be selected as a sample unit.

The balsam woolly aphid, Adelges piceae, has a complex distribution in the crown of trees; The sample universe and sample units are defined, and methods of detecting, monitoring, and measuring population levels at stated levels of confidence, accuracy, and assurance are described. Suggestions are given for sampling aphids on the stems of trees.

Laboratory experiments showed that female Lytta nuttalli Say are capable of developing and depositing more than one batch of eggs. The largest number of batches deposited by a female was 5. Batches laid by one female are the same size, and each batch represents one gonadotropic cycle. Most females lay every 4 to 8 days, the most frequent intervals between consecutive ovipositions being 5 and 6 days. The females copulate at least once before the first oviposition and usually again within 24 h after each oviposition. The first copulation stimulates oocyte maturation and probably also deposition of the first batch of eggs. Additional copulations are not needed for the development and deposition of subsequent egg batches, but appear to stimulate egg output. Sufficient spermatozoa are transferred to the female during the one or more copulations preceding the first oviposition to fertilize all the eggs she produces. The largest number of copulations by a male was 9. Males can copulate as frequently as every 24 h, but the most frequent intervals between copulations in virile males are 2 and 3 days. The basic features of the reproductive cycles of male and female L. nuttalli are found in other Meloinae and probably are characteristic of the subfamily. The fairly large quantities of spermatophoral materials from repeated copulations may be important in the nutrition of the female.