A vehicle-mounted net (“car-net”) is a useful tool to sample flying beetles or other insects. Previous authors have used nets on top of the vehicle. A net mounted lower and in front of the vehicle is thought to be superior for catching beetles which fly closer to ground level. Quantified results are given.

Developmental rates, lower developmental threshold, host selection among three species of aphid, and head capsule width were determined for the parasitoid Aphelinus sp. nr. varipes (Foerster) (Hymenoptera: Aphelinidae). Aphid species used were Russian wheat aphid, Diuraphis noxia (Mordvilko), western wheat aphid, Diuraphis tritici (Gillette), and corn leaf aphid, Rhopalosiphum maidis Fitch. Developmental rate was determined at five constant temperatures, 11.3, 14.7, 19.0, 25.7, and 30.3°C. Developmental times of the wasp were similar in Russian and western wheal aphids, ranging from 88.7 days al 11,3°C to 11.3 days at 30.3°C. Lower developmental threshold was similar in both species, 9.7°C in Russian wheat aphid and 9.4°C in western wheat aphid. Because of the low number of corn leaf aphid s parasitized, it was not possible to compute a parasitoid development threshold in that host. In the host selection test, there were no significant differences in numbers of Russian and western wheat aphids attacked; corn leaf aphid was seldom attacked. The western wheat aphid is a native species that also causes leaf-rolling; we believe it was the primary host of the parasitoid before the arrival of the Russian wheat aphid. Wasps emerging from Russian wheat aphid were consistently larger than those emerging from western wheat aphid. Mean head capsule width for 30 female wasps from Russian wheat aphid was 0.33 mm; from 30 female wasps from western wheat aphid mean head capsule width was 0.20 mm.

Plusiotis prototelica sp.nov. from Baja Verapaz, Guatemala, is described and illustrated. A key to the prasina species group of Plusiotis, including the new species, is presented. Characters of P. prototelica that could allow it to be placed in the genus Chrysina Kirby are mentioned.

The cylindrical bark beetle, Lasconotus intricatus Kraus., is attracted to multiple-funnel traps baited either with black spruce logs infested with male four-eyed spruce bark beetles, Polygraphus rufipennis (Kirby), or the male-produced aggregation pheromone, 3-methyl-3-buten-1-ol. The addition of the host terpenes, bornyl acetate and β-pinene, to 3-methyl-3-buten-1-ol reduced the attraction of L. intricatus. 3-Carene, myrcene, and α-pinene appeared to have a partial inhibitory effect. Catches in spring and summer disclosed a high degree of temporal coincidence between the two species. We hypothesize that L. intricatus utilizes the aggregation pheromone of P. rufipennis as a host-finding kairomone.

Haemolymph from Colorado potato beetles at larval, pupal, and adult stages was analyzed for pH, osmolality, and concentrations of magnesium, calcium, potassium, sodium, chloride, phosphate, and citrate. Differences in the concentrations of some ions observed between stages were used to formulate physiological saline solutions for the adult and larval stages.

In the field, superparasitism of Lymantria dispar (L.) by Parasetigena silvestris (Robineau-Desvoidy) was not the result of random oviposition, but, because parasitoid eggs were aggregated, certain hosts were more likely to be parasitized than average. Parasitoid eggs were more aggregated when gypsy moth larvae were collected from under burlap bands than when larvae were collected elsewhere in the same 9-ha plot, resulting in lowered mortality due to parasitism. This finding suggests that collecting larvae from burlap bands may not provide accurate estimates of the impact of P. silvestris on populations of L. dispar. In laboratory studies, deposition of more than one egg on a single host significantly increased parasitoid emergence and host mortality. However, increasing superparasitism had a negative effect on both the probability that an individual parasitoid would survive to emerge from a host and the size of the puparium produced by the parasitoid. The probability of parasitoid survival was higher when fifth- rather than fourth-instar gypsy moth larvae were attacked, but puparia produced by parasitoids emerging from fifth-instar larvae were smaller.

The Nearctic members of the genus Perilissus Holmgren, parasites of various species of sawflies on coniferous and deciduous trees and shrubs, were revised. There are 17 species of which 10 were described as new. These were placed in six species groups as follows: the discolor group composed of P. concavus, P. impunctatus, P. gilvus, P. triangularis, P. galbipes, P. rutilus spp.nov., and P. discolor (Cresson); the araius group comprising P. araius Burks and P. helvus sp.nov.; the coloradensis group composed of P. coloradensis (Ashmead) and P. spatulatus sp.nov.; the anatinus group consisting of P. anatinus sp.nov.; the bicolor group including P. bicolor (Cresson), P. townesi Burks, and P. cancellatus sp.nov.; and the concolor group comprising P. concolor (Cresson) and P. decoloratus (Cresson). Relationships of the genus Perilissus with other genera within the tribe Perilissini were discussed. Also, presumed relationships of the species groups and species of Perilissus were interpreted.

Larval features of the anisodactyline genus-group taxa Anisotarsus Chaudoir, 1837, Amphasia s.str. Newman, 1838, Xestonotus LeConte, 1853, Spongopus LeConte, 1848, Anisodactylus s.str. Dejean, 1829, Anadaptus Casey, 1914, Gynandrotarsus LaFerté-Sénectère, 1841, and Geopinus LeConte, 1848 are described. Keys to first instars and to second and third instars are included. Possible relationships between the genus-group taxa studied are discussed. Based on larval character states, Geopinus, considered as a distinct genus, could be more appropriately treated as a subgenus of Anisodactylus. The taxon Spongopus, included by recent authors as a subgenus of Anisodactylus, does not share two synapotypic character states of the genus Anisodactylus and could be more appropriately treated as a distinct genus.

A study was conducted to evaluate changes in rangeland grasshopper communities over a 5-year period in the Agropyron spicatum (Pursh) Scribn. and Smith and Bouteloua gracilis (H.B.K.) Lag. provinces of the steppe region of Montana, USA. Results showed that it was possible to categorize years into outbreak, non-outbreak, and transitional based on rangeland grasshopper intensity. Nearly twice as many species were observed in outbreak versus non-outbreak years. Of the 57 total grasshopper species collected over the entire study period, 16 species were found only during outbreak years and only two were found exclusively during non-outbreak years. Of the remaining 39 species collected during outbreak and non-outbreak years, 27 species showed no significant differences in the percentage of the community that they represented and 11 species showed significant increases. The only species that made up proportionately less of the community as densities declined from outbreak to non-outbreak was Melanoplus sanguinipes (F.). Although M. sanguinipes, Ageneotettix deorum (Scudder), and Aulocara elliotti (Thomas) were the three top-ranked species in both outbreak and non-outbreak years, M. sanguinipes contributed most to overall shifts in grasshopper intensity. Results support the hypothesis that grasshopper communities overall are sensitive to temporal changes in resources, even though responses of individual species differed.

Acephate implanted in trunks of black spruce, Picea mariana (Mill.) B.S.P., trees in the fall, 3 weeks before female bud flush, and at female bud flush reduced insect damage to cones and increased seed yields for 1 year. Second-year effects of the implants reduced insect damage to cones, but without increased seed yields. In the 2nd year, cones from trees treated at bud flush had the least insect damage and the highest residues of acephate and its toxic metabolite, methamidophos. Damage to treated cones by the spruce cone maggot, Strobilomyia neanthracina Michelson, the dominant insect in untreated cones, was insignificant in the 1st year and was reduced in the 2nd year.

Male genitalia of Choristoneura species from the Nearctic Region and Palaearctic Region are described and illustrated. The study revealed that the male genitalia are among the most important body parts that contain valuable morphological characters for species distinction or grouping in this genus. They are potentially useful in the clarification of the taxonomic status of species in closely related species groups, such as the spruce budworm species complex in North America.

On the basis of 17 interpretable male genital characters and their corresponding evolutionary states, the phylogeny of the genus Choristoneura is inferred and proposed. Nine species groups are recognized: (1) fumiferana, pinus, biennis, orae, occidentalis, lambertiana, carnana, retiniana, and spaldingiana; (2) diversana, murinana, metasequoiacola, and jezoensis; (3) longicellana; (4) lafauryana; (5) conflictana and fractivittana; (6) hebenstreitella, adumbratana, and luticostana; (7) albaniana and lapponana; (8) rosaceana and parallela; and (9) obsoletana and zapulata.

Morphological evidence obtained in the present study suggests that two conifer-feeding species groups of Choristoneura, species group 1 from the Nearctic Region and species group 2 from the Palaearctic Region, are related. They represent the least evolved species groups in the genus. Choristoneura rosaceana, C. parallela, C. obsoletana, and C. zapulata, representing some of the species feeding on deciduous trees, are among the most evolved Choristoneura species.

This revision recognizes 13 species of Stilpon Loew in the Nearctic Region, including nine new species. A key is provided for the identification of adult specimens, all species are described, and their geographical distributions are mapped. Two informal species groups are recognized in the Nearctic Region, with the following included species: (1) S. graminum group — S. campestris Cumming sp.nov. (type-locality Assiniboia, Saskatchewan, Canada); (2) S. varipes group — S. chillcotti Cumming sp.nov. (type-locality 10 km E Evergreen, Alabama, USA), S. ctenistes Cumming sp.nov. (type-locality Salmon Creek, New York, USA), S. curvipes Melander, S. limitaris Cumming sp.nov. (type-locality Sapelo Island,Georgia,USA), S. pauciseta Melander, S. pilomus Cumming sp.nov. (type-locality Franconia, New Hampshire, USA), S. spinipes Melander, S. tribulosus Cumming sp.nov. (type-locality Gatlinburg, Tennessee, USA), S. tyconyx Cumming sp.nov. (type-locality Bedford, Massachusetts, USA), S. varipes Loew, S. vockerothi Cumming sp.nov. (type-locality Ottawa, Ontario, Canada), and S. wirthi Cumming sp.nov. (type-locality Dennisport, Massachusetts, USA). A world list of described species of Stilpon, including synonyms, is provided. Stilpon pectiniger Melander is a new junior synonym of S. varipes Loew and S. demnatensis Vaillant is indicated as a nomen nudum. Stilpon pleuriticus Melander, previously considered to belong within Stilpon, is excluded from the genus, and S. obscuripes Adams is transferred as Crossopalpus obscuripes (Adams) comb.nov. Lectotypes are designated for S. pauciseta Melander and S. pectiniger Melander. Homologies of previously confused structures of the male and female terminalia are summarized with reference to other Empidoidea. The monophyly of Stilpon is justified, including discussion of the phylogenetic relationships of the genus to the remainder of the Tachydromiinae. All described species of Stilpon, including extralimital species, are assigned to one of three proposed informal species groups (S. divergens, S. graminum, or S. varipes group), and zoogeographic patterns are discussed.

The larvae of eight Nearctic sawfly species in the genus Dolerus are described here for the first time. Six species, D. aprilis, D. tibialis conjugates, D. gilvipes albifrons, D. apricus, D. acidus, and D. subfasciatus, were reared from adults collected on the field horsetail, Equisetum arvense Linnaeus, and the larvae of two species, D. sericeus and D. nitens, were collected on grasses. The life history of Dolerus spp. is described. An illustrated key to the species dealt with is provided. Taxonomic affinities among. the species are briefly discussed.

The mating behavior of spruce budworm [Choristoneura fumiferana (Clem.)] moths was studied in a wind tunnel. Of 88 contacts between male and female moths, 64 (73%) resulted in successful copulation. Failures were a result of males losing contact during courtship (11%), and females walking or flying, either when first contacted (7%) or when males attempted copulation (9%). Females showed no overt behavior other than moving away. Removal of the male labial palps had no effect on responses, which indicates that these structures have no role in courtship. Males with antennae completely removed did not respond to airborne pheromone and, therefore, none copulated. Removal of one antenna or half of both antennae of the males did not reduce the numbers of males that located females, but did result in slower responses and fewer matings. It also resulted in changes in male courtship behavior, which suggest that males depend upon their antennae to position themselves appropriately alongside the female when attempting to copulate. Analyses of male response to models of female moths constructed from glass rods with wings of male spruce budworm or male white-marked tussock moth [Orgyia leucostigma (J.E. Smith)] attached showed that males position themselves approximately halfway along me wing length of the model, with no dependance on its wing size or the length of the male’s antennae. Responses were equally high to both spruce budworm and to tussock moth wings, but no males responded to glass rods in the absence of wings.

Morphological, life history, and distributional data are presented for North American species of the genus Chelomideopsis Romijn. Chelomideopsis brunsoni (Cook) and C. besselingi (Cook) are redescribed on the basis of larvae, deutonymphs, and adults. Larvae and female adults of C. brunsoni, and deutonymphs of both of these species, are described for the first time. The mite described by Cook (1955) as the allotype female of C. brunsoni is correctly identified as a female of Platyhydracarus juliani Smith (1989). Four new species are described as follows: C. occidentalis sp.nov. (deutonymphs and adults), C. siskiyouensis sp.nov. (adults), C. minuta sp.nov. (female adults), and C. gledhilli sp.nov. (adults). A new diagnosis is proposed for Chelomideopsis based on knowledge of all active instars. New hypotheses on the phylogeny of species of the genus are presented, permitting the first assessment of zoogeography in this group of mites. The genus probably originated in Laurasia during the late Cretaceous or early Tertiary, and diversified and became widely dispersed in North America and Eurasia during the Tertiary. Mites of the genus apparently were adapted for the temperate climate that persisted until late Tertiary times, and were displaced to southern refugial areas by habitat destruction and climatic cooling associated with episodes of Pleistocene glaciation. The various species are now beginning to reinvade recently deglaciated areas from their Wisconsinan refugia, as they and their host chironomids colonize suitable spring and small stream habitats.

This review article starts with the discovery of Bacillus thuringiensis Berliner in Japan at the turn of the century and notes that the observations of the early Japanese workers clearly show that they were aware of the toxin-mediated nature of the activity of B. thuringiensis toward insect larvae. The early work in Europe with B. thuringiensis against Ostrinia nubilalis (Hubner) showed that the bacterium had promise as a microbial control agent. The commercial development of B. thuringiensis in France in the late 1930s, and in Eastern Europe and the United States in the 1950s, is traced.

The cabbage root maggot, Delia radicum (L.), was the only Delia species capable of attacking undamaged roots of canola [oilseed rape, Brassica napus (L.)] that was found in commercial fields in Manitoba. Adults of the overwintering generation infest canola. Their progeny, adults of the first generation, left the maturing plants after completing a single generation. Root maggot damage occurred in fields in all agricultural regions of the province. The mean percentage of the roots with damage was higher in the more northerly agricultural regions (15.8%) than in the south (8.0%). Most of the damage was light and the damage did not visibly affect the growth or vigour of the plants. Foot rot fungi were not associated with the feeding damage. In cage experiments, the seed yield of canola did not decrease with increasing proportions of plants damaged by D. radicum. The percentage of plants with root maggot damage (DAM) was best described in a polynomial by the mean daily air temperature (TEMP) and the total precipitation (RAIN) for June and July:

log(DAM + 1)=–12.3 + 0.66 TEMP + 0.09 RAIN – 0.004(TEMP × RAIN).

The level of damage caused by the larvae of D. radicum to canola in commercial fields during the years 1985 through 1988 did not appear to have caused yield losses. However, the level of damage increased with increasing precipitation and temperature during June and July so a series of favourable years could lead to increased damage and possibly to significant yield losses.

Cyzenis Robineau-Desvoidy is a member of the Goniini, a tribe characterized by the production of microtype eggs in adult females. A new concept of Cyzenis is proposed based on a synapotypic character state of adults, i.e. the presence of narrowly separated discal scutellar setae. Two monophyletic species groups are recognized, containing a total of five species in the Nearctic Region: the albicans-gcoup with C. albicans (Fallén) (a species introduced to North America from Europe), C. pullula (Townsend), and C. browni (Curran); and the incrassata-graup with C. incrassata (Smith) and C. ustulaia (Reinhard). A Palearctic species, C. jucunda (Meigen), is recognized as a member of the albicans-group. Phorocera anassa Reinhard is newly synonymized with C. incrassata. Phorocera festbums Aldrich and Webber, Phorocera mitis Curran. and Phorocera regilla Reinhard are transferred from Cyzenis to Eufrontina Brooks (new combinations). A lectotype is designated for C. albicans (Fallén). Nearctic species of Cyzenis are keyed and redescribed, their distributions are mapped, and external, terminate, and puparial features are illustrated. Distinction of individuals of C. albicans and C. pullula is discussed in relation to ecological studies on die host–parasite pair of C. albicans and the winter moth, Operophtera brumata (Linnaeus) (Lepidoptera: Geometridae).

In laboratory and field experiments involving artificial and real tree trunks, all larval instars of gypsy moth [Lymantria dispar (L.)] crawling on a horizontal surface were influenced by the diameter, height, and species of a tree. For most larval instars, black artificial tree trunks were preferred to white trunks. The influence of the diameter and height of a host on larval attraction was examined with cardboard columns. The degree of larval attraction to a column of a certain diameter and height was positively correlated with the angle at which the column was presented. Significantly more larvae were attracted to bolts of red oak (Quercus rubra L.) than to white birch (Betula papyrifera Marsh.) or trembling aspen (Populus tremuloides Michx.). The implications of these findings and their possible effects on host colonization are discussed.

Aspects of cold hardiness of Phytoseiulus persimilis Athias-Henriot and Amblyseius cucumeris (Oudemans) were compared. Mean supercooling points (SCPs) ranged from −19.4 to −27.1°C and increased during development from egg to adult. Feeding status, diapause, and low temperature acclimation had little or no effect on supercooling capacity. Temperature/mortality curves confirmed that both species, including A. cucumeris in diapause, are freezing intolerant in the sense that the SCP represents the absolute limit to low temperature survival. However, the mites survived exposure to −12.5°C for less than 90 min. The results suggest that the SCP is directly related to body mass in these mites and that their ability to supercool is primarily a physical characteristic rather than an adaptation for survival of exposure to subzero temperatures.