Captive colonies of Bombus terricola Kirby received pollen for 8, 14, or 24 h per day from the time of onset of second brood oviposition until colony decline. The pattern of change of worker body size over time, especially between the first and second broods, varied according to these experimental food regimes. The results indicate that conflicting results reported in the literature, with respect to changes in worker size over the course of colony development, probably can be regarded, at least in part, as the outcome of differences in food supply.

Mass trapping for control of the spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.), was evaluated during 1986 in one experimental orchard near Jordan Station, Ont., and in three commercial orchards in Norfolk County, Ont. Multi-Pher II® traps were used to trap adult males, and Vineland traps were used to monitor adult activity and to obtain a measure of the effect of mass trapping on adult male abundance. In the experimental orchard, Vineland trap catches were similar in the trapped and control plots. In two of the three commercial orchards Vineland trap catches were significantly smaller in the trapped plots during one of the three yearly activity periods. Pre-adult leafminer density was significantly lower in the trapped than in the control plots on three of the seven sample dates in the experimental orchard whereas in the commerical orchards, where up to 91 times as many adult males were trapped per plot per activity period, pre-adult density was significantly lower in the trapped plots only in one orchard on one sample date.

The efficacies of cypermethrin, deltamethrin, permethrin, endosulfan, methoxychlor, carbofuran, chlorpyrifos, dimethoate, and malathion were evaluated against the wheat midge, Sitodiplosis mosellana (Géhin). Methods are described for evaluating damage and protection in individually collected wheat heads and whole plants. Weighted values from whole plants provided the best indication of kernel protection and yield response.

Whole plants contained three main types of wheat heads (primary heads, first tillers, and second tillers) which differed in their frequencies, kernel numbers, and developmental times. The latter indicated that the chronology of midge attack, status of midge infestations during spraying, and spray coverage also differed in the head types.

Insecticides provided different levels of kernel protection within and among the various head types. The majority of primary heads emerged before spraying and harbored midge eggs at spraying. In these wheat heads, chlorpyrifos, endosulfan, and malathion provided significantly better kernel protection (60–75%) than permethrin, deltamethrin, and cypermethrin (<7%). The results suggested that the more effective kernel protectants permeated the spikelet and controlled the eggs and/or newly hatched larvae. Kernel protection in the primary heads was closely related to insecticide volatility. Conditions were different in most first tillers and second tillers which emerged after spraying. In these wheat heads, poor spray coverage and short residual activity against adult midge appeared to limit kernel protection by all insecticides.

Two different species of Tinocallis were previously confused under the name T. saltans (Nevsky). The status of the true T. saltans is established by designation of a lectotype from the Nevsky syntype series. The alate vivipara, embryo, alatoid nymph, male, and ovipara of T. nevskyi sp. nov. are described and compared with T. saltans. The new aphid is known from Iran, Pakistan, and Afghanistan and it recently appeared in Europe. A new synonymy is established: T. yinchuanensis Zhang, 1980 = T. saltans (Nevsky, 1929).

The taxonomy, distribution, life history, and host plant relationships of the cochylid moth Agapeta zoegana (L.), an oligophagous, facultatively multivoltine root feeder, are discussed. The results of oviposition and larval feeding tests with 56 plant species in five families are presented and show that A. zoegana is restricted to a few closely related species of Centaurea. In Europe the moth is widely distributed and abundant in the majority of the root-feeding guilds of Centaurea maculosa Monnet de la Marck studied, with densities of 23.6 larvae per 100 roots in eastern Austria/northwestern Hungary and less than 8 larvae per 100 roots in central Hungary and the Alsace. The acceptance of target North American species (the tetraploid form of C. maculosa and the diploid Centaurea diffusa Monnet de la Marck), the damage caused, and the active searching ability rate A. zoegana as a potentially effective natural enemy of spotted and diffuse knapweed in North America. Agapeta zoegana will be especially promising as it predominantly attacks the rosette, which is, according to a recently developed population model for diffuse knapweed in Canada, the most sensitive stage determining equilibrium knapweed density. Agapeta zoegana is compatible with Pelochrista medullana Staudinger (Lepidoptera: Cochylidae), another knapweed root feeder recently introduced into North America, and will complement the seed-feeding species already established. The moth was approved for release in Canada and the USA and has been established in British Columbia since 1984 on C. diffusa.

Examination of crop contents of three species of grasshoppers in outbreak densities on desert grassland of eastern Arizona revealed that all three were ingesting a mixed diet of plants. Crops of nymphal and adult Aulocara elliotti (Thomas) contained an average of 67 and 93% dry weight of grass, respectively, placing this species in both the mixed graminivorous and the graminivorous categories. The preferred host plant of A. elliotti was Bouteloua gracilis (H.B.K.) Lag. but it was not an essential item, as a large population developed in a site where this grass was virtually lacking but other perennial grasses were present. Crops of nymphs and adults of both Melanoplus sanguinipes (Fabricius) and M. cuneatus Scudder contained chiefly forbs (88–100% of dry weight). The principal host plants were Erodium cicutarium (L.) L’Hér., Lupinus brevicaulis Wats., Microsteris gracilis (Hook.) Greene, and Plantago purshii Roem. & Schult. Both species of Melanoplus fit into the forbivorous category and evidence indicated they were in competition with each other for food. All three grasshopper species showed preferences for particular plant species and as a consequence had significantly different frequencies of plant taxa in their crop contents from what were present in the field.

The following new taxa of Xantholininae are described: Lithocharodes scutifer sp. nov. (Arizona), Habrolinus californicus sp. nov. (California), H. hardyi sp. nov. (California and Oregon), H. abdominalis sp. nov. (California), H. andrewsi sp. nov. (California and Oregon), Linohesperus spiculifer sp. nov. (California), L. iaculator sp. nov. (California), L. montivagus sp. nov. (California), L. priapus sp. nov. (California), Neohypnus coloratus sp. nov. (Florida), Oxybleptes meridionalis sp. nov. (Florida).

The genus Timagenes Smetana 1982 is placed as a subgenus of the genus Habrolinus Casey 1906 (new status). The treatments of the genera Habrolinus and Timagenes in my revision (Smetana 1982: 134–143) are entirely rewritten. A new key to the known species of Linohesperus Smetana 1982 is given.

Additional data on taxonomy, bionomics, and geographical distribution of many species of Xantholininae in North America are presented.

A cardboard trap, painted yellow and coated with STP® oil treatment, was more efficient in trapping Myzus persicae (Sulzer) than water traps using Stickem®. STP-coated traps were more selective than Stickem-coated traps for small insects and caught more aphids per unit area than did water traps. Aphids were identified in situ on STP traps more quickly than from water traps or traps coated with Stickem.

We provide keys for identifying the 26 bumble bee species (Bombus and Psithyrus) found in Canada east of Manitoba, and information on their ecology and distribution. The keys are designed for field use and rely primarily on colour patterns rather than on microscopic features.

Oviposition rate (eggs per ♀-degree-day) and fecundity (total number of eggs per ♀) were measured in two populations of Melanoplus sanguinipes (F.) under natural conditions during two seasons (1984, 1985). Differences in fecundity between the two seasons were indirectly associated with differences in time of hatching. In 1985, females hatched earlier and had shorter preoviposition periods, greater longevities, and higher oviposition rates; consequently, fecundity averaged about three-fold greater than in 1984. Longevity appeared to be the most important single determinant of fecundity. Maximum fecundity was 73.2 eggs (equivalent to four pods) and mean fecundity ranged between 10.1 and 28.9 eggs per female.

A method was developed for estimating attack and brood totals of the mountain pine beetle in part or all of the infested bole of individual lodgepole pine trees. The method requires measurement of tree height, tree diameter at 1.37 m, and maximum height of attack, and tallying of brood and attacks on paired 20 cm by 30 cm samples centered at 1.22 m on the bole. Attack and brood totals are estimated in two ways: (1) as a product of the variables (a) total bole surface area, (b) proportion of bole surface area infested, and (c) mean attack/brood density; and (2) regression on the combined variables of tree diameter, infested height, and attack/brood density at 1.22 m on the bole. An approach to developing variance estimates for brood and attack totals is discussed.

A species of the genus Monotarsobius, M. kojimai sp. nov., is described from Japan. This species is characterized by having a notable swelling on the dorsal side of tarsus I of the 15th leg in the male.

A new species of crabronine wasp, Crabro canningsi, is described from the Yukon. Its relationships with other species are discussed and additional records of Crabro species in the Yukon are presented.

Distribution of grasshopper populations was examined on a rural municipality (RM) basis over a 44-year period in Saskatchewan. A two-state Markov chain probability model was used to describe the transitional probabilities from high or low populations for different time steps. The analysis showed significant persistence of grasshopper populations in particular locations but the degree of persistence varied between RMs. The probability model was used to determine the expected duration of outbreaks or recessions. The potential usefulness of estimates of the expected duration of an outbreak is discussed in relation to crop protection.

Grapholita libertina Heinr. larvae are a pest of economic importance in lingonberries (partridgeberries), Vaccinium vitis-idaea L. var. minus Lodd, in Newfoundland. Both domestic and export markets are affected. Surveys conducted during the period 1973–1982 to determine distribution and larval population levels, in localities where berries were harvested commercially, indicated they were infested to varying intensities in all 15 localities studied. Highest infestations occurred at Pouch Cove (5 September 1974 — 122 larvae per kilogram of ripe berries) and on Witless Bay Line (9 August 1977 — 276 larvae per kilogram of green berries).

In experiments conducted from 1980 to 1982 at six locations, there was a significant decrease in level of infestation as the crop reached maturity. Our results suggest that delaying the opening of the lingonberry harvest season until the last week of September decreased the risk of infestation.

Observations on the life history of G. libertina and a naturally occurring hymenopterous parasite are presented.

A standardized bioassay procedure was used to determine median lethal doses (LD50) of the microsporidium, Nosema fumiferanae (Thom.), on newly molted fourth- and fifth-instar eastern spruce budworm larvae (Choristoneura fumiferana (Clem.)). The LD50 for fifth-instar larva was 1.23 × 106 ± 2.82 × 105 spores. The fourth-instar LD50 was 2.23 × 104 ± 4.30 × 103 spores per larva for populations experiencing prolonged post-diapause cold storage or an elevated temperature during diapause and 2.00 × 105 ± 6.66 × 104 spores per larva for populations not experiencing stressful conditions during and after diapause. Median lethal times (LT50) ranged from 6 to 19 days, depending on instar and dose level. Sublethal responses of fourth- and fifth-instar larvae inoculated with serial dilutions of spores were estimated by significant linear models. These regressions were negative for pupal weight and adult longevity and positive for development time (duration of instar VI). Inoculations of newly molted sixth-instar larvae produced similar models, although development time was not significantly affected. Insects reared following stress during and after diapause had consistently longer developmental times. The importance of prolonged developmental time on disease expression and insect susceptibility is discussed.

Aspergillus parasiticus Speare and Beauveria bassiana (Bals.) Vuillemin were isolated from melanopline grasshoppers in Saskatchewan in 1986 and 1987. The pathogenicity of these isolates for Melanoplus sanguinipes (Fabricius) nymphs was assessed by topical, oral, and injected applications of 1.0 × 103, 104, or 105 conidia per individual. The A. parasiticus isolate was pathogenic to M. sanguinipes by injection and topical application but not orally. The B. bassiana isolate was pathogenic when injected or topically applied resulting in high mortality (82–100%), at all doses tested, between days 3 and 5 post-inoculation. Beauveria bassiana was infectious, at the highest dose tested, when orally applied with the majority of mortality occurring between 7 and 14 days post-inoculation.

The tribal and subtribal structure of the braconid subfamily Opiinae is dismantled, and several changes in the generic classification are made. Thoracoplites Fischer and Aspilodemon Fischer are removed from the Opiinae. Utetes Foerster and Pseudorhinoplus Fischer are elevated to generic rank and Bracanastrepha Brèthes is treated as a subgenus of Utetes. Five generic names currently in use are treated as synonyms of Opius Wesmael, Rhinoplus Foerster is synonymized with Biosteres Foerster, and Kephalosema Fischer is synonymized with Hydrangeocola Brèthes. Relationships of species groups formerly included in the subtribe Biosterina are discussed in phylogenetic terms.

A combination of published techniques provided point estimates of life history parameters for two natural field populations of Melanoplus sanguinipes (F.) in crested wheatgrass pastures. Stage-specific survival rates averaged 0.4798, 0.2261, 0.7628, and 0.6903 for egg, instars I–III combined, instar IV, and instar V, respectively. Daily survival rates of adults averaged 0.9702, but were slightly lower for females than for males. Estimated duration of nymphal instars averaged 8.4 days, the adult preoviposition period averaged 13.3 days, and adult longevity averaged 26.7 and 36.3 days in the two populations. Oviposition rates were estimated for up to four successive ovipositions, and net replacement rates of populations also were estimated. Neither population replaced itself, indicating that potential capacities for increase were not approached under conditions of these studies.

We examined the within-crown distributions of male and female bagworm, Thyridopteryx ephemeraeformis (Haworth), pupae on Juniperus virginiana L. as a function of prior defoliation. This was to evaluate the hypothesis that the differential movement of females to the upper crown before pupation would be strongest on heavily defoliated trees. Differential stratification of the sexes occurred irrespective of degree of defoliation, and despite the fact that competition, as evidenced by higher mortality of pupae and reduced weight of egg masses, was apparently greatest at the top of moderately and severely defoliated hosts. There was no relationship between height of pupation and risk of parasitism for either sex. Female larvae were ca. 4-fold more likely than males to abandon a low-lying host upon which they had fed and to ascend the trunks of nearby trees before pupating. Enhancement of larval dispersal by females is the most plausible explanation for the stratified distribution of bagworm pupae within trees.