Two species of cone maggots, Strobilomyia Michelsen, are known to attack seed cones of spruces in North America. Seed cones of black, red, and white spruce from Newfoundland to Alberta were collected to determine the number of host species and the distribution of these maggots. Strobilomyia appalachensis Michelsen was obtained only from seed cones of black and red spruce, whereas S. neanthracina Michelsen was obtained only from white spruce seed cones. Our observations represent the first record of S. appalachensis in Canada. We conclude that, like S. neanthracina, S. appalachensis has a transcontinental distribution, but exploits different hosts, namely black and red spruce. We also observed that S. appalachensis was capable of extended diapause.

Infrared thermometry was investigated as a diagnostic tool to detect root injury in corn caused by feeding of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Plots were infested with 50–1000 eggs per plant, and the study was conducted over 2 years. Differences (P < 0.05) in canopy temperatures were detected in severely infested plots in 6 out of 13 days and 7 out of 11 days on which measurements were made during the period of feeding by rootworm larvae in 1989 and 1990, respectively. Temperature differences between the air and leaves from infested plants were never greater than 3.5 °C and usually occurred within ± 1 °C. Feeding by rootworm larvae at infestation levels of less than 200 eggs per plant could not be detected with infrared thermometry. Above densities of 200 eggs per plant, increases in canopy temperatures corresponded with increases in the level of infestation with rootworm eggs, and with reduced plant height, and lower grain yield. Losses in grain yield due to rootworm infestation were manifested through smaller cobs and fewer seeds per cob. Kernel weight was not affected by rootworm feeding. Crop maturity was delayed at infestation levels of 1000 eggs per plant.Elevated canopy temperatures induced by rootworm feeding were detected through infrared thermometry in commercial corn fields, however differences (P < 0.05) in canopy temperatures were noted only after 10 July. Although these data show that elevated canopy temperatures induced by rootworm feeding can be detected with infrared thermometry, some inconsistency in results was observed. Various reasons for why the technique was not more reliable are discussed.

The nine species; of Timema Scudder known previously from California, Arizona, and Nevada are redescribed and three new species are added: Timema nakipa from Baja California, Mexico: T. tahoe from Nevada; and T. cristinae from Santa Barbara County, California. Timema nakipa and T. podura Strohecker are the only representatives of Timema known from Mexico. Keys and identification tables are presented for identification of species.

Use of gerrids (Hemiptera: Gerridae) as primary hosts by the solitary egg parasitoid Lathromeroidea sp.nov. is established and parasitoid reproductive behaviour is described. Four species of Limnoporus (L. dissortis Drake and Harris, L. notabilis Drake and Hottes, L. rufoscutellatus Latreille, and L. esakii Miyamoto) and two of Gerris (G. buenoi Kirkaldy and G. pingreensis Drake and Hottes) were successfully parasitized in the laboratory. A greater proportion of wasps eclosed successfully from eggs of Gerris than from Limnoporus. Host size was directly proportional to both weight and body length of adult parasitoids. Sex ratios were female-biased, with males emerging before females.

Five cycles of single-plant and progeny-row selection in lines derived from Brassica rapa L. "Tobin" were used to identify plants with incomplete resistance to flea beetles, Phyllotreta cruciferae (Goeze). This line, called C8711, had higher survival, grew larger, and yielded more seed than Tobin when the two lines were compared in field plots at Glenlea, Manitoba, unprotected by insecticide. C8711 without insecticide yielded more seed than Tobin treated with a lindane seed dressing, but less than Tobin treated with carbofuran granules. With carbofuran, which prevents most flea beetle damage, the yield of C8711 was 35% higher than for Tobin. At Saskatoon, Saskatchewan, the differences between C8711 and Tobin were not statistically significant, although the trends were similar to those at Glenlea. C8711 was late maturing, produced small seed, and was not of canola quality. The resistance in C8711 is attributed to a low level of antixenosis, rapid growth at the cotyledon stage, and tolerance to damage during the first 3–4 weeks of growth.

Mites of 10 genera and one undescribed taxon of Pyemotidae were found on specimens of 10 genera of beetles of farm-stored grain or grain residues. Four species of the mites are known to be associated with stored products. Almost 10% of beetles carried mites. Most of the mites were found on the abdominal tergites, under the wings of the beetles, but Tarsonemus spp. were found on external surfaces of beetles. Hypopi of Acarus farris (Ouds.) are recorded for the first time as subelytral phoronts of grain beetles. Mites can occasionally be found in fungal mycelia attached to beetles.

The thickness of the wall of the puparium of the apple maggot, Rhagoletis pomonella (Walsh), increased as the puparium aged. The force required to pierce the wall of the puparium also increased with age, and this relationship was best described by a cubic polynomial. Increasing thickness and hardness of the wall of the puparium will likely influence the efficacy of the parasite Phygadeuon wiesmanni Sachtl.

The daily patterns of activity of females of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin), were observed in controlled laboratory conditions and in field conditions in eastern Saskatchewan in mid-July 1986 and 1987. In the field, during the daytime, females rested on stems of wheat plants within 30 cm of the ground and, at approximately 2000 hours CST, flew up to wheat heads. Most oviposition took place between 2000 and 2145 hours (or 75 min before, to 30 min after, sunset). Toward the end of the oviposition period, females were frequently seen drinking dew from wheat heads. On some evenings, females migrated down from the heads following oviposition, but on more than half of the evenings they remained on the heads until early morning. However, they never moved down to the low level they occupied during the day until the next morning, when the migration was usually complete by 0900–1000 hours. Light intensity appeared to regulate the vertical migration of females. Cloudy conditions may allow an earlier onset of oviposition. Flight was limited to air temperatures above 14–15 °C and oviposition to temperatures above 10–11 °C. Wind speeds of 10 km per h or more and rain occasionally limited activity. In the laboratory, oviposition activity occurred almost exclusively during the scotophase, mainly in the first 2 h. Mean total fecundity was 83.6 ± 10.9 (±SE) eggs, and mean longevity was 6.6 ± 0.6 days. No oviposition took place on the 1st night, and the greatest mean daily fecundity occurred on the 3rd night.

Descriptions are given of the fundatrix, alate and apterous viviparous females, ovipara, and the alate male of Sitobion blackmani sp.nov., collected on ocean-spray, Holodiscus discolor (Pursh) Maxim, ssp. discolor.

Two techniques for sexing adults of the white pine weevil Pissodes strobi Peck are described. Both techniques are based on the external anatomy of the terminal segments of the abdomen as viewed with a dissecting microscope.

Laboratory observations on the biology of Ceranthia samarensis (Villeneuve), a tachinid parasitoid of the gypsy moth, were carried out in the laboratory at 22 °C day/15 °C night, 85–90% RH, and a 12L:12D photoperiod. Older (5–6 days post-eclosion) males mated readily with newly emerged females. Mating success was 60%. The gestation period of the mated females was 10–12 days. Laboratory-reared (on diet) second- and third-instar gypsy moth larvae feeding on newly grown foliage of Quercus rubra L. were exposed to gravid females of the parasitoid. Ceranthia samarensis ovolarviposited on the body of the host. The first-instar larva penetrated the host cuticle and developed internally, forming a respiratory funnel that caused a dark circular scar on the lateral side of the caterpillar. The average number of progeny (puparia) produced over the lifetime of a C. samarensis female was 55.0 ± 5.0 (SE) and average longevity was 4.1 ± 1.7 (SE) days. Diapause of the puparia was facultative and induced by temperatures below 20 °C combined with a 12L:12D photoperiod. In nondiapause individuals, total generation time was 22–40 days. To obtain diapause insects, puparia were stored for2monthsat 15 °C, 100% RH, and 12L:12D photoperiod for development of pharate adults. Cold storage at 2–4 °C and 100% RH for at least 5 months was required to obtain up to 75% eclosion after 5–9 days the following year.

Diumal patterns in yellow sticky trap catch of pear psylla, Cacopsylla pyricola Foerster, are described for the spring (reproductive) winterform generation, summerforms, and the fall (diapausing/dispersing) winterform generation. For each life stage, trap catch of the two sexes is also compared, and sex ratios on sticky traps are contrasted with independent estimates of population sex ratio obtained by beat tray samples. Beat tray estimates of sex ratio showed a slight male bias for both winterform generations (although P = 0.09 for spring winterforms), and a female bias for the summerform samples. Sticky trap catches were significantly male biased for the reproductive generations (i.e. spring winterforms and summerforms). Trap catches of fall winterforms were not different from a 1:1 ratio. The male bias for the reproductive generations may be due to mate-seeking activities of males or to a decrease in activity by egg-laden females. Peak catch for summerforms occurred in the morning, and that of both winter-form generations occurred at midday. There was no evidence that trapping depleted local densities of psylla during a 24-h period.

Larvae and adults of Mamersellides costenius sp.nov., from Mexico and Florida, USA, are described. The resulting new morphological data are incorporated into revised diagnoses for the genus Mamersellides, the subfamily Anisitsiellinae, and the family Anisitsiellidae. Preliminary assessment of character states exhibited by larvae and adults of Mamersellides and other genera of Lebertioidea, and by those of genera of the family Limnesiidae, suggests that a comprehensive cladistic analysis would provide a phylogenetic basis for extensive revision of the classification of these mites.