A key, based on morphological characters of adult males, separating six traditionally recognized conifer-feeding Choristoneura species, C. pinus Freeman, C. lambertiana (Busck), C. fumiferana (Clemens), C. occidentalis Freeman, C. biennis Freeman, and C. orae Freeman occurring in Canada and Alaska is provided and illustrated. The newly discovered morphological features, the aedeagus of C. fumiferana and C. pinus with a short apical spine and with many microscopic spicules on the distal half, are used to separate these two species from their western allies C. occidentalis, C. biennis and.C. orae.

Post-harvest grain temperature and moisture were consistently higher at the center than at the edge roof openings of steel granaries in Manitoba in 1982 and 1983. In 1982, temperatures at the center were significantly higher in infested than in uninfested granaries and declined only slowly during a 2-week period. Several kinds of insects were found in grain samples or in beetle-detection traps inserted into grain at the center location but none was found in grain or in traps at the edge. The heaviest infestations coincided with the temperatures and moistures at the center. In 1983, initial temperatures at the center and edge roof openings were high when the granaries were filled but declined rapidly, particularly at the edge, during the next 2 months. Between late August when the granaries were filled and early November, moisture content increased at the center and edge roof openings. It was significantly greater at the surface than at a depth of 20–130 cm. Insects were found in traps inserted 1 m into the grain at the center location. The results indicate that the most likely place to find insects in filled granaries is at the center near the surface and the most opportune time to begin checking the grain is 2 months after the granaries have been filled.

A standard test for the larvicidal activity of Bacillus thuringiensis (B.t.) against the larvae of the sunflower moth Homoeosoma electellum (Hulst) has been developed. Bioassay parameters investigated include diet preparation, concentration of B.t., effect of formaldehyde, and method of pathogen incorporation in diet. The LC50 for seconded third-instar larvae is 1.24 μg of Dipel® WP ml−1 or 19.8 IU B.t. ml−1 pathogen-incorporated diet. Layering of a pathogen-suspension upon the surface of the diet was not a reliable bioassay technique for H. electellum. The addition of formaldehyde in the diet reduced the slope of the dose–mortality curve but did not change the LC50.

The influence of nitrogen levels in foliage of white-fir, Abies concolor, and Douglas-fir, Pseudotsuga menziesii, seedlings on various biological characteristics of the western spruce budworm, Choristoneura occidentalis Freeman, was studied. Seedlings were grown under greenhouse conditions and provided with nutrient solutions to maintain five foliar nitrogen levels ranging from 1.29 to 4.42% dry weight for white fir and 1.43 to 3.94% for Douglas fir. Larvae confined to treated seedlings were monitored through the next generation. Larval mortality was higher, and development time longer, at both upper and lower extremes of foliar nitrogen than at mid-level. Mean pupal weight was significantly greater for larvae reared on white fir with the mid-range foliar-nitrogen level. Mean number, and weight, of eggs laid were highest when larvae fed on foliage from the mid-range nitrogen level. Total number of larvae produced was lowest at the high and low extremes of foliar nitrogen levels.

Predation on spruce-budworm, Choristoneura fumiferana (Clem.), pupae on the forest floor was estimated at 72.5% per day. It is unlikely that many adults of the spruce budworm emerge from the forest floor and there would be little bias introduced in the estimation of apparent fecundity by disregarding pupae on the ground. There were large seasonal fluctuations in the rate of predation attributable to various predator groups; the overall rate ranged from 66 to 91% per day. Low temperatures had no detectable effect on vertebrate predation, but reduced invertebrate predation; however, this effect is unlikely to result in much variation in survival of pupae on the forest floor.

The generic placement of Tanypus pallens Coquillett, 1902 is changed to Conchapelopia s. str., with a redescription given of the male holotype. As a result Conchapelopia (s.s.) gonoides (Subi.) becomes a junior synonym of Conchapelopia (s.s.) pallens (Coq.). The status of Larsia pallens (Coq.) sensu Roback 1971 with its synonymies are discussed.

The larvae and pupae of Stictochironomus marmoreus (Townes) and S. quagga (Townes) are described. Diagnostic features of the larvae of S. marmoreus and S. quagga are found in the relative lengths of antennal segments 2 and 3, in the length of the antennal blade, and in the size of the mental teeth. The pupae can be distinguished by the conformation of the shagreen pattern on tergites II–V and the number of spines in the caudolateral comb on abdominal segment VIII. Preliminary keys to known Nearctic larvae and pupae of Stictochironomus are given.

The pheromones lineatum and (+)-sulcatol were used in traps in a sawmill to survey the ambrosia beetles Trypodendron lineatum (Olivier) and Gnathotrichus retusus (LeConte) respectively. Spatial and temporal distribution patterns for both species were identified. This information can be used for the establishment of a pheromone-based mass-trapping program for ambrosia beetles. The addition of ethanol and α-pinene to traps baited with (+)-sulcatol significantly increased the catches of G. retusus.

The responses of 11 population samples of sixth-instar larvae of the western spruce budworm, Choristoneura occidentalis Freeman, to carbaryl spray were determined. Representatives of one population each from Arizona, Idaho, Montana, New Mexico, and Washington were included. Five response levels of progressively higher tolerance were apparent; the most tolerant population sample was ca. 18 times more tolerant than the most susceptible sample to carbaryl. Trends in relationships of site characteristics and response to carbaryl were not evident. Previous spray history of an area, however, appeared to be related to response at a site; populations from sites sprayed with DDT were significantly more tolerant than those from sites where DDT had not been used. The most tolerant groups were collected from a Montana population in an area where both DDT and carbaryl had been applied. The electrophoretic characteristics of each population sample were determined. No loci detectable by electrophoresis were correlated with response to carbaryl.

In the subfamily Tanypodinae (Diptera: Chironomidae), 11 pairs of setae and 3 pairs of sensory pores are found on the larval head capsules. The structure and position of these cephalic setae and sensory pores exhibit strong generic differences but vary little between species within a genus. A generic key to the Tanypodinae utilizing these differences is presented for larvae of the following genera: Clinotanypus, Coelotanypus, Natarsia, Tanypus, Djalmabatista, Procladius, Psectrotanypus, Brundiniella, Macropelopia, Ablabesmyia, Guttipelopia, Hudsonimyia, Krenopelopia, Labrundinia, Larsia, Monopelopia, Nilotanypus, Paramerina, Pentaneura, Telopelopia, Thienemannimyia, Trissopelopia, and Zavrelimyia. The delineation of the frontoclypeal apotome can be used to distinguish fourth-instar from third- and earlier-instar larvae.

The thyantae group of Trissolcus is characterized by the presence of abundant long setae on the metapleuron. All known New World species occur in the Nearctic, viz. T. thyantae Ashmead (eastern USA and Canada), T. occiduus n. sp. (western USA), T. parma n. sp. (widespread), and T. ruidus n. sp. (Arizona, New Mexico). An identification key is provided and all species are described or redescribed. Data on distributions and hosts (Heteroptera: Pentatomidae) are summarized.

In 1982 and 1983, silhouette traps, sticky traps, and suction traps with and without dry-ice bait were evaluated for sampling populations of black flies that are pests of cattle in central Alberta. The dry-ice-baited silhouette trap was the most effective. The black-fly species collected were Simulium arcticum, S. aureum, S. decorum, S. meridionale, S. tuberosum, S. venustum, S. verecundum, S. vernum, and S. vittatum. Approximately 80% of the black flies collected each year were S. arcticum, the primary pest species of cattle in Alberta.

The taxonomy, distribution, and ecology of the Holarctic species of Agabus (Coleoptera: Dytiscidae) are reviewed. Seventeen species occur in both the Nearctic and Palaearctic regions. The following new synonymy is proposed (valid name given last): A. solus Leech = A. adpressus Aubé; A. sharpi Jacobson and A. pseudoconfertus Wallis = A. opacus Aubé; A. kenaiensis Fall = A. wasastjernae (Sahlberg) and A. hudsonicus Leech = A. zaitzewi Poppius, thus each of these species is recognized for the first time as being Holarctic. The Nearctic species A. ontarionis Fall is reduced in status to a subspecies of A. fuscipennis (Payk.). Agabus congener (Thunb.) is redefined and Nearctic specimens formerly placed in the species are assigned to A. thomsoni (J. Sahlberg). The reports of Palaearctic occurrence of A. approximates Fall and A. discolor (Harris) are considered to be in error, the records referring to A. levanderi Hellén.

Melanoplus sanguinipes (F.) is one of several species of grasshoppers that periodically causes severe economic damage to cultivated crops and rangeland plants in western Canada and the USA. The usual method of controlling outbreaks of these pests has been the application of broad-spectrum chemical insecticides, such as malathion, an organophosphate, and sevin, a carbamate (Blickenstaff et al. 1974; Onsager 1978). These insecticides can cause undesirable environmental side effects.

Chow and Mackauer (1984) recently reported on inter- and intraspecific larval competition between Aphidius smithi Sharma & Subba Rao and Praon pequodorum Viereck (Hymenoptera: Aphidiidae), when both were parasitizing the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae). In interspecific competition, a 1st-instar Praon larva usually eliminated, by physical combat, an Aphidius larva that was up to 48 h older. However, circumstantial evidence suggested that once an Aphidius larva had reached an advanced stage of the final (4th) instar, it was able to complete development and pupate, even in the presence of a younger Praon competitor.

The northern subarctic region is the limit of the distribution of Drosophilidae (Toda 1984); the family is of tropical origin (Throckmorton 1975). Hence, a drosophilid community inhabiting the northernmost subarctic region is likely to have a relatively simple community structure. This note presents information on the habitat preferences of a drosophilid community at Inuvik (68°22′ N, 133°45′ W) in the Mackenzie delta, Northwest Territories, Canada.