Quantitative sampling schemes for estimating within-tree populations of attacking Dendroctonus frontalis Zimmerman were investigated. Accuracy and precision of five small sample procedures were affected by the number and location of the sample heights, the number of sample disks per sample height, and the techniques used for calculating infested surface area and average insect density. Best small sample estimates were obtained from samples near the middle of the infested bole. Unbiased, minimum variance combinatorials were derived. High precision estimates were obtained only by sampling the infested bole at frequent intervals.

In northern California Parargyractis confusalis has two to three generations per year, depending on climatic conditions. Adults lead a terrestrial life, though the female re-enters the water to oviposit. The eggs, larvae, and pupae exist underwater and have been collected to a depth of 4.3 m. Larvae occur in lakes and streams and are most abundant in areas where the water velocity is between 0.4 and 1.4 m/sec. Factors influencing the distribution and density of this species include water temperature, concentration of dissolved oxygen, substrate texture, and algal growth.

The following new odontiine taxa are described: Clupeosoma cicatricale, Sumatra; C. margarisemale, Java; C. microthyrale, Sabah; Hydrorybina fulvescens, Sumatra; Hemiscopis intermedialis, Soemba; Platynoorda, and its type-species P. atrivittalis, Sabah; Porphyronoorda, and its type-species P. decumbens, S. India; Gononoorda, its type-species G. neervoorti, Java; also G. jacobsoni, Sumatra. Hydrorybina Hampson is removed from the synonymy of Clupeosoma Snellen, and is redefined. In addition to the type-species, H. polusalis (Walker), and the new species H. fulvescens, the genus includes two species, Anemosa pryeri Butler and Clupeosoma violascens Hampson, transferred as new combinations from Clupeosoma. Syllythria bicolor Moore, placed first in Hydrorybina then in Clupeosoma by Hampson, is considered probably odontiine but probably not a member of either of those genera. It is left in Clupeosoma pending further investigation. Eurycreon? rubralis Warren is removed from the synonymy of C. bicolor and is transferred to the subfamily Pyraustinae as Pyrausta rubralis (Warren), n. comb. The relationship of Hydrorybina to Hemiscopis Warren is pointed out, and differential characters are given. Micromania Swinhoe, with type-species M. stigmatalis Swinhoe, is removed from the synonymy of Hemiscopis and is transferred to the subfamily Nymphulinae in the vicinity of Paracymoriza Warren, which is removed from the synonymy of Parthenodes Guenée. Noorda moringae Tams and N. trimaculalis Amsel are transferred to Epinoorda Rebel as new combinations.

Field testing of a large number of synthetic compounds and several combinations of them revealed that male moths of the darksided cutworm, Euxoa messoria (Harris), were attracted to combinations of Z-7-hexadecen-1-yl acetate and Z-11-hexadecen-1-yl acetate. The most satisfactory attractants were combinations of these two compounds in ratios of 1:20 or 1:40. The presence of small amounts of the corresponding E-isomers did not interfere with the attractant. The diene, Z-7, Z-11-hexadecadien-1-yl acetate, in combination with Z-11-hexadecen-1-yl acetate also attracted the males, but there was no advantage in using the diene in place of Z-7-hexadecen-1-yl acetate.

Spalangiopelta ciliata n. sp. is described and represents a new record for the subfamily Ceinae (Pteromalidae) in North America.

First to sixth generation offspring of samples of the German cockroach, Blattella germanica L., collected from various areas in Canada were tested for resistance to various insecticides applied topically. All collections showed a high level of resistance to chlordane, some resistance to propoxur and malathion, and little or none to chlorpyrifos and diazinon.

A general population model for cotton growth and development is presented. The model captures the essential properties of the biological processes, and is sufficiently flexible to the incorporation of complex physiological and behavioral characteristics. The model has been used successfully to simulate the growth and development of Acala SJ-II cotton in California. The mathematical framework for coupling plants and herbivores has been presented, and the biological implications of their damage to the plant examined in a very general way.

Anopheles stephensi Liston larvae were reared in food- and space-limited environments to which a mixture of penicillin G, chloramphenicol, and amphotericin B was added to suppress microbial populations. Under crowded conditions larvae took longer to develop, exhibited reduced survival, had an extended pupation period, and produced adults that were smaller. Under uncrowded conditions slightly more males than females emerged, whereas under crowded conditions proportionately fewer males than females emerged. Indirect evidence suggested that inhibitory compounds that slowed development and increased larval mortality were produced by crowded larvae. The addition of antibiotics did not suppress all microbial populations, but rather selected for resistant Pseudomonas-group bacteria which actually increased in number. The addition of antibiotics increased developmental rates at uncrowded, but not crowded densities, increased larval mortality, and increased the size of the emerging adults. Residual antibiotics increased development rates in a subsequent bioassay of the rearing media.

Ingestion of a phenyl-benzoyl urea [1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)-urea] by Diprion similis (Hartig) interferes with molting. At the highest concentration (1% solution) tested, it prevents ecdysis but does not prevent apolysis. The Cuticle of pharate larvae is thinner than normal but the formation of melanin in the cuticle is not inhibited. At a concentration of.01%, ecdysis is usually completed but many survivors fail to feed following the molt. This failure is associated with the accumulation of a fibrous material in the midgut. Prior to the molt, food consumption as measured by faecal output is not impaired.

The study examined quantitatively the effects of embryonic development in the preceding fall and cumulative heat units from 1 April to 31 July in the current year on density trends of three major grasshopper species (Melanoplus sanguinipes (Fabr.), M. bivittatus (Say), and Camnula pellucida (Scudder)) in Saskatchewan. The influence of adult density of the previous year, embryonic development, heat units, and their interactions were examined by multiple regression analyses for each of the three species to determine their contribution to next year’s adult populations. The models tended to underestimate density during a population increase and to overestimate during a population decline. Combined heat units during the preceding fall and following spring indicated that a general increase in density should occur when heat units were equal to or greater than 1600 °D50.

The structure and behavior of a sterile male intergeneric hybrid tenebrionid beetle from the Namib Desert are described. Compared with the courtship performance of males of the parental types the hybrid male was intermediate in choice of females. The parental species occur together in the field and there is a broad habitat overlap in utilized parts of the environment. Intergeneric courtship was regularly observed, but only one instance of hybridization was noted.

Euxoa auxiliaris (Grote) females yielded the largest amount of extractable pheromone after they were stored at least 44 days at 10 °C and then 7 days at room temperature. The males would not respond to the pheromone until they were 28 to 37 days of age and their clearest responses were between 2 and 4 h of the dark cycle. Agrotis orthogonia Morrison females produced pheromone within 1 day after emergence and 2-day-old males responded to it between 5 and 7.5 h of the dark cycle when the olfactometer background light intensity was 0.35 lux. Female Euxoa tristicula Morrison produced pheromone 3 days after emergence and the males responded between 3 to 5 h of the dark cycle.

Post-attack injections of full- and half-strength Silvisar 510 (cacodylic acid) appear to inhibit populations of Dendroctonus rufipennis (Kirby) more effectively than quarter- and tenth-strength dilutions. Arsenic concentrations in the phloem were highest in the full-strength treatments and progressively decreased in the lesser strength treatments. Arsenic concentrations in the phloem were generally highest just above the frill while concentrations at 20 ft and higher above the frill were significantly lower than those just above the frill. Arsenic concentrations in the needles were highest in the full- and half-strength treatments and decreased progressively in the lesser strength treatments. Concentrations in the needles were essentially equal in the upper and lower portions of the crown. Arsenic concentrations in the soil were not affected by the treatments.

Studies on the flue-cured tobacco losses caused by the natural tomato hornworm, Manduca quinquemaculata (Haworth), were conducted in the field at Delhi, Ont., during 1973, 1974, and 1975. The feeding habits of the larval stage were observed and data on the subsequent damage to tobacco were recorded Two to six leaves per plant, depending on leaf size, were unmarketable due to damage caused by one hornworm larva. The most severe damage by the larva was due to destruction of terminal buds.

The tobacco yield was significantly related, negatively, to the tomato hornworm infestation levels. All infestation levels influenced quantitative tobacco losses, but no qualitative differences were apparent when compared with the yield in the insect-free plots. Maximum yield losses occurred at the highest level of infestation. There were no significant differences in yield losses per larva among the infestation levels or among the years. The average yield reduction per larva for all of the population densities and years was 0.70 oz of cured leaves. A prediction equation to establish the relationship between hornworm infestation levels and tobacco yield losses was calculated. A theoretical economic-injury level for the tomato hornworm on tobacco in Ontario was established.

As a result of alar tagging migrating specimens of the monarch butterfly (Danaus p. plexippus L.) in North America over a period of 25 years, it was possible to plot the migration routes establishing two large overwintering colonies, one located in California and the other in mountains of the Sierra Madré Occidentale in Mexico. Photographs of the two overwintering populations are presented together with release–recapture lines showing the direction of migration from breeding areas to the two overwintering sites. Data, presented for the first time, show the migration routes of the Western population from the breeding areas in the mountains and west of the mountains to California.

A population of the white fir needle miner, Epinotia meritana Heinrich (Lepidoptera: Olethreutidae), infesting white fir, Abies concolor (Gord and Glend.) Lindl., was studied in southcentral Colorado. Adults oviposited from mid-June through mid-August. Eggs were deposited on the concave side of needles, near the base. Larvae hatched in late July and August, then mined needles 1 or more years old before overwintering inside the first or second mined needle. In the spring, each larva mined one or two additional needles before pupating in the last needle during May or June. There was one generation per year.

White firs of all age classes were subject to defoliation, but tops of codominant trees were most heavily damaged. Oviposition occurred most often on 3–5 year old needles and larvae generally did not move to another year’s foliage. Apanteles (Braconidae) was the most prevalent parasitoid observed, causing about 11% larval mortality.

Experiments with caged populations of Anopheles stephensi Liston were performed to evaluate the effects of larval intraspecific competition on adult density and sex ratio. The changing of the water in continuous culture cages prevented the accumulation of larval competitive compounds and excretory products, and resulted in higher adult densities and the successful emergence of proportionately more males.

Catches of male clover cutworm moths with Z-11-hexadecen-1-yl acetate containing 10.8 to 25.0% Z-11-hexadecen-1-ol decreased linearly as the percentage of alcohol increased. The largest catches were with the acetate containing 10.8% alcohol, and at a concentration of 5 mg/rubber carrier. This bait was effective in the field for at least 4 weeks Catches of moths with the attractant on polyethylene carriers were independent of the attractant concentrations, and were significantly less (P < 0.01) than with the same attractant concentrations on rubber carriers.

Mature larvae and puparia of Canace macateei Malloch inhabiting mats of blue-green algae in a Massachusetts intertidal marsh are described and compared with other larvae of the Canaceidae.

Adults of Phytoptus oculatus n. sp. are described. These are unusual among Eriophyoidea in possessing eye-like structures lateral to the prodorsal shield. Diagnoses for the genus Phytoptus and two provisional species groups within the genus are included.