When the Zeugloptera are compared with advanced Lepidoptera three major changes in the hind wing base are noticed:

1) The apparent loss of the prescutal arm which is fused to the second basalare in Ditrysia.

2) The separation of the prescutal apodeme from the prescutum by membrane so that the third tergopleural muscle appears to insert on the mesopostnotum.

3) The reduction of the median plates and the development of cubital plates.

UC-62644, a moult-inhibiting insect growth regulator (IGR) belonging to the benzoylphenylureas, had an EC50 of 0.1 to 0.2 ppm in a meridic diet for the 3rd to 6th larval instars of the spruce budworm, Choristoneura fumiferana Clemens. The effects of the IGR were apparent in less than 48 h after ingestion and there was evidence for some contact toxicity. The larvae were unable to discriminate between IGR-treated and untreated diet. Experimental aerial application of the IGR revealed that at <70 g in 4.7 1/ha (1 oz in 0.5 U.S. gal/acre) it effectively controlled spruce budworm populations and afforded foliage protection. These results were comparable with those obtained with Matacil® applied at the recommended rate.

Four families of parasitic mites (Acari: Rhinonyssidae, Ereynetidae, Cytoditidae, and Turbinoptidae) have evolved independently to live inside the nasal passages of birds. A previous survey of nasal mites in Canada drew attention to the dearth of knowledge about these specialised mites, and indicated there were more species of nasal mites to discover in Canada. Since 2008, we have continued to survey nasal mites and herein present the details from infested hosts, 92 host individuals representing 64 species from 11 orders and 23 families. We report 18 new records for species of nasal mites in Canada: 16 Rhinonyssidae, one Ereynetidae, and one Turbinoptidae. No Cytoditidae have yet been recorded in Canada. We also collected five undescribed species of rhinonyssids. A total of 64 host-parasite species records are reported, and of these records, 52 rhinonyssids, one ereynetid, and three turbinoptids are new for Canada. Nasal mites were not collected from 127 host species, and several of these host species were sampled extensively (⩾50 individuals). This research furthers our understanding of avian nasal mites in Canada and highlights the need for continued investigations on these mites.

Records indicate that the present outbreak of the larch sawfly in Manitoba and Saskatchewan began about 1938 in the Spruce Woods-Riding Mountain area of Manitoba. Since then, it has spread in all directions where the principal host tree, larch, Larix laricina (Du Roi) K. Koch, occurs. It now includes nearly all of Manitoba and Saskatchewan, northwestern Ontario, part of northeastern Alberta, and northern Minnesota. In 1944, an annual survey of parasites that attack larvae of the larch sawfly was begun by the Forest Biology Laboratory, Winnipeg. The purposes of the survey were to determine (a) the principal species of parasites, (b) their abundance and effectiveness, and (c) .host-parasite population trends.

Receptive fields of the infrared receptors located in sensory pits adjacent to the mesocoxal cavities of Melanophila acuminata were measured using a goniometric apparatus and plotted on a Mollweide homolographic projection. The receptive fields extend mainly in a lateral and ventral direction. The total receptive area in units of solid angle is 5.80 steradians but the simultaneous field of perception of infrared radiation of all the sensilla in a pit is only 0.42 steradian. Based on these findings and on other evidence we believe that the infrared-sensitive sensilla function during flight and are used by these beetles for detecting point sources of heat, such as forest fires, from long distances.

An onion maggot, Hylemya antiqua (Meigen) (Diptera: Anthomyiidae) strain, having low level (≤ × 5) resistance to organophosphorus insecticides, was selected with parathion to determine if higher resistance levels to the selection agent and other insecticides used for onion maggot control would result. Parathion resistance levels increased to ×10.1 and ×23.8 after 4 and 14 generations of selection, respectively; without further selection, resistance levels declined by ca. 1/2 in 6–7 generations. Parathion resistance was ×24.4 after 20 generations of selection and resistance levels to ethion, diazinon, fonofos, and carbofuran were 2 to 3 times higher than those measured initially. The pattern of resistance development in field strains of onion maggot collected in 1975 and 1980 was similar to that observed in the laboratory selection program, but resistance levels were lower, probably because of lower selection pressure and the variety of chemicals used under practical conditions. After 14 generations of parathion selection, resistance levels were ×23.8 and ×10.1 to parathion and carbofuran, respectively. After 12 additional generations of carbofuran selection, carbofuran resistance increased to ×31.2, while the level of parathion resistance remained the same.

Cohorts of instar I larvae of the Douglas-fir tussock moth, Orgyia pseudotsugata, were stocked on branches of white fir, Abies concolor. Branches were either exposed naturally over drop-trays or protected with cages of nylon netting. Only 8.7% of the larvae in exposed cohorts survived to pupate, compared with 68.0% survival in caged cohorts where dispersal and predation were prevented. Losses from the exposed cohorts were caused mostly by arthropod predation, disappearance, and non-replaced dispersal. Disappearance of early larvae was attributed primarily to predation by spiders and insects while disappearance of late larvae was suspected to be due mostly to bird predation. In an analysis of k-values, actual or suspected predation accounted for 47.2% and dispersal 40.5% of the total loss.

Frequency modulation has been discovered in the calling song of a conocephaline katydid, Conocephalus nigropleurum (Bruner). Real time sound spectrum analysis reveals a drop of 5 khz during the closing wingstroke.

Evidence is presented for the presence of a sex attractant in female Vitula edmandsae (Packard). The ability of the virgin female to attract the male varies with age, reaching a maximum 2 days after emergence.

The pheromone-producing gland is a ring-shaped structure formed by modification of the epidermal cells in the intersegmental membrane between the eighth and ninth abdominal segments.

South American Trichogrammatidae are poorly known. In this paper we describe a new species of Trichogramma and two new species of Uscana from Chile. The Trichogramma species belongs to the perkinsi group and parasitizes the eggs of Rhyacionia buoliana (Lepidoptera: Tortricidae). One Uscana species belongs to the senex group (new name proposed for the B group) and parasitizes eggs of Pseudopachymerina spinipes (Coleoptera: Bruchidae), and the other Uscana species belongs to the fumipennis group (new name proposed for the C group) and parasitizes eggs of Bruchus pisorum (Coleoptera: Bruchidae). These new species might be useful in biological control, especially against R. buoliana and B. pisorum, important pests of pines and peas, respectively, in Chile.

Three pyrethroids, deltamethrin, fenvalerate, and cyfluthrin, were assayed against 2nd-instar nymphs of the grasshopper Melanoplus sanguinipes (Fab.) at 5 dosages and at 5 post-treatment temperatures ranging from 15.6 to 37.8°C. All three showed a negative temperature coefficient of toxicity but there was considerable variation in the pattern of response. Deltamethrin proved to be the most effective and cyfluthrin the least effective, both in terms of the amount of active ingredient required for 90% mortality and in having the lowest negative coefficient, respectively. The extent of the negative temperature coefficient of toxicity was much more pronounced at the LD90 than the LD50. Apparent mortality was recorded at 24, 48, and 72 h post-treatment and with each of the pyrethroids, recovery of some hoppers took place after 24 h. This phenomenon of delayed recovery was greatest at the lower temperatures.

Frontalin, a synthetic pheromone, induces attacks by the spruce beetle (Dendroctonus rufipennis) on baited standing trees, in which most broods fail. The impact of baiting 100 randomly chosen trees was determined by estimating the beetle population in a 766-ha spruce forest. Attack density in infested bark was similar for wind-thrown and baited trees; however, 95% of attacks occurred on the former, which were more numerous and had greater attacked surface areas. In this forest, it is estimated that 34 frontalin-baited trees would have been required for each windfall to trap 90% of the beetle population.

Severe mortality (93%) of overwintering larvae of emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), was recorded in March 2016 from green ash, Fraxinus pennsylvanica Marshall (Oleaceae), in Syracuse, New York, United States of America. In contrast, larvae collected from the same area in January exhibited <1% mortality. A strong cold front moved across New York from 13 to 15 February 2016 with temperatures plunging to nearly −40 °C in some areas. In many regions of New York where A. planipennis is established, temperatures dropped well below the reported supercooling point of overwintering larvae. To evaluate whether the extreme cold was linked to extensive mortality of larvae, trees were sampled from four areas that experienced a gradient of minimum temperatures on 14 February 2016. Overwintering mortality varied from ⩽5% to 93% among regions, with lowest survival in the coldest regions. When excised from their galleries, dead larvae were discoloured with brown spots or had black necrotic tissue in the spiracles or foregut. This is the first report of extensive cold-related mortality for this species in North America and highlights the stochastic nature of climatic extremes on invasive species populations.

Daily periods of activity of eight colonies of the eastern tent caterpillar, Malacosoma americanum (F.), were monitored photoelectronically under a simulated springtime photoperiod in the laboratory. Colonies averaged 3.7 ± 0.1 (S.E.) activity periods per day (N = 103 colony-days), separated by an average interval of 6.6 ± 0.1 h (N = 389). Foraging trips lasted an average 2.8 ± 0.1 h (N = 397). A plot of 336 activity period midpoints (seven colonies) showed all colony activity peaks to occur between 0600 and 0800 h, 1100 and 1600 h, 1900 and 2100 h, and 0100 and 0400 h. The first three peaks correspond well to previously reported field observations but the early morning foraging trip, which occurred in darkness, was previously unreported by field investigators. The temporal placement of activity peaks shifted from day to day within colonies but the occurrence of evening foraging trips was the most consistent. Dark onset appeared to trigger foraging in resting colonies. Recruitment of hungry caterpillars to food finds appears to be a common component of the foraging strategy of this species.

It was very difficult to decide whether to introduce this paper by discussing taxonomic problems in the genus Euxoa and how certain different approaches might help to solve them, or whether first to describe a number of different approaches and then to reveal that the genus Euxoa provides an excellent opportunity to try them out. Chronologically speaking the second alternative is the more correct, the approaches existed and their acknowledgment was followed by the recognition and definition of a suitable problem.

Bioassays and direct counts were used to assess the abundance of resting spores of the gypsy moth, Lymantria dispar (L.), fungal pathogen, Entomophaga maimaiga Humber, Shimazu and Soper in forest soils. Resting spores in soil collected in October, January, and March and held under refrigeration germinated as readily as spores collected in April, but those collected in April germinated faster. Bioassays of resting spores in soils from different sites in Connecticut were directly related to results obtained from physically counting spores in the soil, and weakly correlated with a previously developed forest-based bioassay. The number of resting spores in a site was inversely related to the number of years since the site had last been defoliated by the gypsy moth, resulting in an implied maximum viability of resting spores of about 10 years. This maximum longevity was similar to a direct measure of long-term resting-spore viability. The study implies that resting-spore load in the soil may be an important determinant of the ability of the pathogen to control the gypsy moth.

The North American genus Ceratagallia Kirkaldy, 1907 is redefined to include subgenus Aceratagallia Kirkaldy, 1907 (= Ionia Ball, 1933, syn.nov.) with 78 species in two subgenera. Two additional new species are unplaced to subgenus: C. acerata from Oregon, and C. emarginata from Mexico. The typical subgenus Ceratagallia has 30 species, including C. gillettei (Osborn & Ball, comb.nov.), C. sordida (Oman, comb.nov.), and two new species C. ana from Mexico and C. vipera from Washington state. Subgenus Aceratagallia has 46 species, all new combinations under Ceratagallia. The economic "species" formerly known as "sanguinolenta" is divided into the Canadian clover leafhopper C. humilis (Oman) and the American clover leafhopper C. agricola sp.nov. Other new taxa in subgenus Aceratagallia include 18 new species and seven new subspecies: alaskana (ssp. of siccifolia) from Alaska; omani on the Pacific coast from Oregon to British Columbia; clino and lophia from the Oregon interior; compressa (ssp. of siccifolia), gallus, modesta, okanagana, and zacki (ssp. of nanella) from intermontane valleys of the Pacific northwest and southwestern mountains; interior (ssp. of humilis) and rossi from the Sonoran subregion; australis (ssp. of nanella), coma, ebena, entoma, falcata, oionus, and venosa from Mexico and Texas; alvarana (ssp. of humilis), cerea, cristula, harrisi, semiarida, and viator widespread between the Appalachian and Rocky Mountains; and whitcombi (ssp. of robusta) from Florida to Arizona. Four former species are reduced to subspecies: compacta Oman and poudris Oman in C. robusta (Oman), helveola Oman in C. cinerea (Osborn & Ball), and truncata Oman in C. humilis. The taxa are keyed and illustrated, and their phylogeny is discussed.

A 4000-ha block of spruce budworm, Choristoneura fumiferana (Clem.), infested forest in western New Brunswick was sprayed repeatedly in 1975 during the larval stage of budworm development. The objective was to reduce the population of the 1975 generation to a minimum level so that most of the following generation eggs found on the block could be attributed to invading females, thus providing data on the impact of moth invasion.

The presence of dispersing adults in the airspace over the block was monitored by a ground-based radar unit while light traps and pheromone-baited traps were used to confirm that invasion had taken place. A total egg population of 33.8 masses per m2 of foliage was found on the block and indirect estimates suggest that invading females deposited about 10 of these masses.

This is the third paper of a series on the taxonomy of cocoons and puparia, cast larval skins, and other remains of parasitic Hymenoptera and Diptera that are found in or near the remains of parasitized hosts hfter the parasites have emerged. It deals with the known Canadian parasites of the introduced pine sawfly, Diprion similis (Htg.); previous papers dealt with the known Canadian parasites of the European pine sawfly, Neodiprion sertifer (Geoff.) (Finlayson, 1960a) and the European spruce sawfly, Diprion hercyniae (Mtg.) (Finlayson, 1960b). Parasites of D. similis that werk encountered in either of the nvd previous papers in the series are not described or illustrated here.