Mature larvae of Pissodes strobi (Peck), Pissodes schwarzi Hopkins, Pissodes nemorensis Germar, and Pissodes terminalis Hopping are described and external morphology illustrated. A key to species is presented. A phylogenetic analysis is done using single- and multiple-outgroup comparisons, which both find trees of identical topology. Character states of clypeus pigmentation and premental sclerite shape putatively support a monophyletic relationship of the P. strobi complex.

Several horticultural oils, an insecticidal soap, neem, garlic extract, a sugar ester, and a synthetic insect growth regulator were evaluated under laboratory conditions for their ability to inhibit pear psylla’s [Cacopsylla pyricola (Foerster)] feeding and oviposition. Supreme oil significantly reduced winterform oviposition rates in both choice and no-choice assays and reduced feeding rates in no-choice assays. Supreme oil also reduced oviposition rates of summerform females in choice tests but not in no-choice tests. In addition, summerform oviposition rates were reduced significantly by application of several mineral oils (Orchex 796E, 692, and WS2928) and garlic barrier to pear foliage in no-choice tests, and by all oils, garlic barrier, and M-Pede in choice tests. Summerform feeding rates were reduced by application of mineral oils. Data suggest that "summer type" oils and other compounds may have utility in pear psylla management programs by decreasing feeding and oviposition.

Field-acclimated Drosophila suzukii (Diptera: Drosophilidae) from the Saguenay–Lac-Saint-Jean region, Québec, Canada, were examined over two years for winter survival, under the hypothesis that flies select protected overwintering microhabitats. In 2016–2017, flies trapped alive in the field or emerged from infested fruits were submitted to four winter regimes of either constant or daily fluctuating temperatures of 5 °C (2–8 °C) or 10 °C (7–13 °C). In 2017–2018, two fluctuating regimes averaging either 1 °C (–2 to 4 °C) or 3 °C (0–6 °C) were tested. Survival was modelled using Cox proportional hazard models testing probability that mortality risk varies with cold winter regime, fly sex, and fly provenance. Hazard ratios were about 1.7 times higher for males than for females. Models indicate that flies in constant and fluctuating 10 °C, in constant 5 °C, or in fluctuating 1 °C with daily exposure to –2 °C would not survive a six-month winter. Female survival extended to the next summer in fluctuating regimes averaging 5 °C or 3 °C. Estimates of 0.95 quantile survival (5%) indicate that overwintering D. suzukii experiencing such cold temperature regimes during winter, with no prolonged sub-zero temperatures, could survive until July of the following year, which is likely at the high population densities observed.

Laboratory and field experiments were designed to determine the effect of insect predators on the immature broods of Dendroctonus brevicomis LeConte. The results indicate that predation is dependent on the predator density and the time predator and prey are exposed together. Prey density was generally very high and had little effect on the rate of predation. The corroboration of laboratory and field experiments give confidence to the conclusion that the constant predation rate (0.261 prey per predator per day) can be used to estimate western pine beetle mortality from predation, provided temperatures remain within the 60° to 70°F range.

The wheat midge, Sitodiplosis mosellana Géhin (Diptera: Cecidomyiidae), is a serious pest of spring wheat in North America. Currently, most commercial cultivars in the state of Montana, United States of America are susceptible. A study was conducted to assess the variability of adapted spring wheat cultivars to wheat midge infestations. A secondary objective was to determine the relationship between wheat midge infestation levels and spring wheat agronomic traits, including yield, test weight, grain protein, plant height, and heading date. This relationship was determined by evaluating 16 hard red spring wheat cultivars over a six-year period at the Northwestern Agricultural Research Center, near Kalispell, Montana. Levels of infestation had a negative impact on grain yield and test weight. Overall, the average infestation level was 40 larvae/spike with the lowest being observed with “Reeder” and the highest for “Thatcher”. Concurrently, “Reeder” had the highest yield, whereas “Thatcher” had the lowest yield and the highest grain protein, demonstrating that wheat midge infestations were positively associated with grain protein. Heading date had a positive association with midge density with higher infestations associated with later maturing cultivars. The economic injury level was estimated at 12 and 20 midge larvae/spike for a market price of USD $0.27 and USD $0.16/kg, respectively.

Two strains of the pupal ectoparasite Nasonia vitripennis (Walk.) originally derived from a single laboratory strain exhibited differences in the proportion of adjacent hosts attacked by the parasite following 65 weeks (approximately 32 generations) in experimental parasite–host systems. Strain I parasitized a greater number of adjacent hosts (19.9%) than strain II in the first generation after removal from the multi-cell system. The difference between the two strains and the laboratory strain decreased from the first to the fourth generation indicating a reversion toward a behavior pattern more akin to that of the laboratory strain.

“Godman and Salvin, Rhopal. I., p. 177, 1882, under teh specific name Lacinia, place Saundersii and Tellias, Bates: Quehtela and Ardema, Reakirt; Paupera, Felder; Mediatrix and Misera, R. Felder; Pretoria, Boisduval; Crocale, Edwards; Adjutrix, Scudder, and Adelina, Staudinger; all of which they consider but inconstant forms of one species.

A method of assessing susceptibility of white fir, Abies concolor (Gord. and Glend.) Lindl., by fungal inoculation was tested during an outbreak of the fir engraver beetle, Scolytus ventralis LeC., at Lake Tahoe, California, in 1987 through 1989. A total of 592 firs growing in six forest stands containing trees infested by the beetle were inoculated with the mutualistic fungus, Trichosporium symbioticum Wright. Six weeks later, reaction wounds were characterized by vertical length and resin concentration. After 2 years, 196 (33.1%) of the test firs had been killed by the beetle. Reaction lengths tended to be greater and resin concentrations lower in test firs that died than in those that survived, but predictive accuracy of the wound variables was inadequate on either an individual tree or a stand basis. On an individual tree basis, discriminant functions using either or both of these reaction wound variables as predictors produced overall percentages of correct classification little higher than would be obtained by predicting that all test firs would survive. On a stand basis, regression models using stand means for the wound variables and white fir basal area as predictors statistically explained more than 95% of observed variation in basal area of white fir killed, but another model using only basal area of white fir as a predictor performed nearly as well.

Delia Robineau-Desvoidy (Diptera: Anthomyiidae), including Delia platura (Meigen), are known pests of vegetable crops. Here, three studies were conducted to examine the relationship between Delia species and Phaseolus vulgaris Linnaeus (Fabaceae). Field studies documented a relationship between planting date and occurrence of Delia damage on P. vulgaris. Plantings in mid-June resulted in higher crop yields (mean bean pods per plant) and reduced damage ratings compared with earlier plantings. Late-May and early-June planting dates were not favourable, as they resulted in high damage ratings and low plant survival. Late-June and July plantings resulted in low damage ratings but low crops yields. Growth chamber experiments examined oviposition preference of D. platura females at eight phenological stages for two varieties of P. vulgaris. Results indicated significantly higher oviposition rates on bean plants at early phenological growth stages, with no significant varietal preference shown by maggots. Laboratory experiments quantified the impact of D. platura larval infestation on two P. vulgaris varieties at two growth stages. Results indicated no significant difference in variety choice. Recommendation for planting P. vulgaris to coincide with Delia phenology using a degree-day model is discussed.

This is one of a series of papers on the development of life tables for the larch sawfly, Pristiphora erichsonii (Htg.), by a research team at Winnipeg. Previous papers have described techniques for obtaining population estimates for eggs, cocoons, and adults (Ives, 1955; Ives and Turnock, 1959; Turnock, 1960), and current work is concerned with the development of methods of segregating and evaluating the mortality factors affecting each stage. This paper describes the methods used to evaluate the amount of mortality caused by individual factors in the cocoon stage and discusses the problems of obtaining accurate and unbiased estimates.

The flying season (sensu lato) and emergence period of Anax junius Drury were determined by routine counts of adults and exuvial collections at a small woodland pond m northern Illinois. The flying season, in this case including activity of apparently young adults, was from April to mid-November. Emergence listed 55 days (26 August to 19 October 1965), the pattern being of the "summer" species type. Before emergence began all adults appeared to be mature and oviposition was often seen. After emergence began, apparently young adults predominated and no oviposition was seen.

This paper deals with the Trinidad Tachinids (Diptera) of the group of genera assembled by L. P. Mesnil (1939) as the tribe Winthemiini, of which the type genus is Winthemia R.-D. The group was subsequently recognized by F. I. van Emden (1954) and later by B. Herring (1960) but has not, so far as I am aware, been considered as a taxonomic unit in relation to the tachinids of the Americas. It is simply a relatively small section of the vast mass of genera called by Mesnil (1939, 1944) the Salmaciinae, or as we now say, the Goniinae, defined by the possession of a bristled prosternum, reclinate posterior frontals, a first post-sutural supraalar as strong as or stronger than, the first postdorsocentral, an absence of infrasquamal setulae, a second abdominal segment excavated to the posterior border and a short robust form. From the other Goniinae, the Winthemiini are separated mainly by the hairy “barrette”, the pattern of the humeral bristles and the reproductive habit of depositing large plano-convex undeveloped eggs on the body of the host insect, the ovipositor having the form of a membranous tube, retractile and of moderate length, reinforced by some elongate sclerites.

In the present paper, in addition to the well-known Winthemia and Nemorilla, the genera Hemisturmia and Triodontopyga have been included. The genitalia of all the Trinidad species have been studied. Their structure appears, on the whole, to reinforce the taxonomic status of the group but whether it will survive a more extensive survey of tachinid genera, remains to be seen.Seven species are described as new.

When a crop has been destroyed by the pale western cutworm, Agrotis orthogonia Morr., one to two weeks may elapse before plants of the second seeding emerge. During this time the larvae may be starved or, at least, subjected to a suboptimum food supply. Frequently the second seeding may be of a different crop from the one that was destroyed.

A previous investigation (Jacobson, 1952) showed that mortality of the starved larvae varied directly with temperature and inversely with size of larvae. Seamans and McMillan (1935) reported that, when the larvae were fed various foods, differences were found in the rate of development and survival.

Intensive studies on the population dynamics of the birch leaf miner, Fenusa pusilla (Lepeletier), were carried out in two stands of blue birch at the Morgan Arboretum, Macdonald College, Que., from 1964 to 1966. Life tables for nine and two generations, respectively, showed that mortality of the immature stages was lower on 3- to 5-year-old trees than on 9-year-old trees. The analysis of successive age-interval survivals in relation to generation survival revealed that predation during the late larval stages was the key factor in generation survival of the insect on the younger trees. Desiccation of the leaf during the early larval stages along with predation were key factors on the older trees.

A 5-year study of the black flies of east-central Saskatchewan revealed 21 species, including Simulium incognitum sp.nov. Chromosomal and ecological evidence for reproductive isolation is presented for this new species, formerly known as S. venustum Say CC4, and S. venustum Say CC. All 21 species in the study are associated with productive streams and rivers. As many as nine of these species might comprise the pest assemblage harassing livestock. The major pest, S. luggeri Nicholson and Mickel, is cytologically distinct from populations in the eastern United States on the basis of a two-step, Y-linked inversion in the IIS chromosomal arm. Simulium luggeri is the only livestock pest that breeds almost solely in large streams and rivers. The other eight probable pests breed entirely or partly in streams less than 10 m wide, often below beaver dams, suggesting that management efforts should specifically target these sites.

Reproduction in the Pseudococcidae is usually regarded as being predominantly, if not exclusively, bisexual, though Ferris (1950) has pointed out that within the family as defined by him males are known for only a small percentage of the species described to date. Detailed biological observations have been restricted to those members of considerable economic importance and in regard to reproductive habits there are few specific references in the literature. Hough (1922) in his account of the life history of the clover root mealybug Chnaurococcus trifolli (Forbes) Ferris, stated that no males were seen throughout the period of the observations. James (1937) made a comprehensive study of the reproduction of Planococcus citri (Risso) Ferris, Pseudococcus maritimus (Ehrh) Ferris, P. gahani Green, P. adonidum (Linn.) Ferris, and Trionymus peregrinus Green, and found that parthenogenesis did not occur in any of these species. This confirmed conclusions of earlier workers with Pl. citri (Schrader 1923, Sutherland 1932), and with P. gahani and Phenacoccus gossypii Twns & Ckll. (Basinger 1934). However, Myers (1932) reported parthenogenesis in some of his experiments with Pl. citri but his procedure of isolating females from the cultures after the second moult is clearly open to criticism.

A recent development in microscopy certain to be of great interest to entomologists is the Scanning Electron Microscope. This machine overcomes the difficulties of studying solid surfaces with a standard light microscope and the problems of the extremely small limits of penetration of the electron microscope. This new microscope focuses a stream of electrons into a beam as small as 1 μ in diameter which moves over the surface of the specimen in a regular pattern, causing secondary radiations to emerge from the surface of the specimen. These are collected by a very sensitive detector and converted to an image similar to that produced by a television tube.

Mature larvae and puparia of Compsobata univitta (Walker) found beneath a pile of decaying vegetation by a stream near Austin, Man., are described and compared with immatures of other Micropezidae.