In his recent revision Rupert (1949) has focused attention on the geometrid genus Plagodis. In the present paper the writer presents descriptions of larvae of three of the four Canadian species in this genus and of the larvae of Anagoga occiduaria (Wlk.) and Hyperetis amicaria (H.-S.). Forbes (1948) notes that these three genera make a neat subgroup in the tribe Anagogini and indicates that there are differences in the larvae. From studies during the summer of 1949 it was determined that there are differences in these larvae; and the differences, along with the similarities, are set forth in this paper.

Certain species of Aedes occurring in North America have been considered difficult if not impossible to identify from adult females alone. Five band-legged species, Aedes excrucians (Walker), A. stimulans (Walker), A. fitchii (F. & Y.), A. riparius D. & K., and A. increpitus Dyar, are in this class. They form a compact group, and female specimens have been very difficult to identify with assurance. Matheson (1944) used mesonotal colour and mesepimeral bristling for separating most specimens of these species. To these characters Gjullin (1946) added the colour of the torus and of the palp, but he also was unable to definitely identify some specimens of excrucians and fitchii. Ross (1947) used the characters employed by Matheson to separate stimlans, fitchii, and excrucians, but admitted that the characters are often unsatisfactory.

One of the most essential procedures in the identification of many Lepidoptera is an examination of the genitalia, and for a most critical examination of these organs slide mounts must be prepared. In many cases, the preparation of slides is one of the most neglected arts in lepidopterology. This is to be deplored, for a well-prepared slide is not only handsome but also much more valuable taxonomically than a messily prepared one. For large and medium-sized specimens, I have found the following technique very gratifying in producing slides of uniformly high quality. Certain phases of the technique are not particularly well adapted for working with smaller moths.

Head: Black, sometimes reddish on the lower facial and parafacial areas. Pollen silvery, but with distinct pale-yellow cast on parafrontal, parafacial, occipital orbit, and anterior part of gena. Frontals 9-11, moderately divergent below, reaching middle of sccond antennal segment. Two or 3 hair-like interfrontals on upper part. Ocellars moderate. Preverticals strong. Outer verticals hair-like. Orbitals nil. Parafacial hairs irregularly scattered, a little stronger below, but not bristly. Occipital fringe of black bristles and hairs, a few of the latter arising in the intrapostocular area (occipital orbit). Behind the fringe an irregular second and sometimes a partial third row of black hairs. Beard white, extending a little in front of metacephalic suture. Front ¼ head width, (average of 5 specimens, 0.256). Gena ⅓ eve height. Antenna ⅔ length of face, black,apex of first and second and base of third segments reddish. Second segment ½ length of third. Arista moderately plumose on basal ⅗ Palpi and proboscis black.

In the winter of 1939 a sample of mites from salted steer hides was sent to me from Buenos Aires for identification with the note that they were present in great numbers in this habitat. As upon examination these appeared to constitute a new species sufficiently unlike the existing representatives of the genus Pontoppidania to preclude its inclusion in that group, the erection of a new, but closely allied genus, seemed to be warranted. Because of the peculiar nature of its habitat and because of its association with hides the name Diphtheroglyphus has been given to this group.

In July, 1947, a leafhopper was found causing serious injury to the foliage of loganberries in the Brentwood area of Vancouver Island, B.C. A survey made at that time in southern Vancouver Island showed that this species was widely distributed, and that it occurred also on raspberries and blackberries. In 1948 it was again found injuring loganberries on Vancouver Island and was found also in the lower Fraser Valley; and in 1949 it was observed 40 miles north of Victoria, at Cowichan Bay, feeding on wild blackberry. It is probable that this species had been present in the coastal area of British Columbia for some time before it was first observed in 1947 causing economic damage.

Although DDT gives excellent control of the striped cucumber beetle, Acalymma vittata (F.), the most serious insect pest of cucumbers in Canada, the technical grade of DDT is generally considered too toxic to cucumbers to he used on that crop with safety. Recently, two related materials that are said to be less toxic to cucurbits in general have been on the market: high-setting-point DDT, and methoxychlor. Carruth and Howe (1948) showed that DDT approaching aerosol grade in setting-point was less injurious to squashes than DDT of technical grade. Several entomologists have reported that cucumbers, like melons and squashes, show definite varietal responses to DDT. Hervey and Schroeder (1946) found the variety Ohio 31 to be more severely injured by DDT than China or Chicago Pickling. Wilson and Sleesman (1947) reported that plants of Ohio 31 were stunted much more by DDT than those of National. This paper is a report on three seasons' investigations of the toxicity of three per cent technical-grade DDT dust to 12 varieties of cucumbers, and one season's investigations of the toxicity of three per cent high-setting-point DDT and methoxychlor dusts to the same 12 varieties.

Aggregations of various species of spring-tails on the surface of the snow have been noted and reported upon by several authors. Of these species, the one occurring most commonly is Achorutes socialis Uzel (Podura nivicola Fitch) which Folsom (1916) records as being a common species in most parts of Europe and occurring in several localities in the north-eastern United States. MacNamara (1919b) studied the habits of this species as it appeared in the vicinity of Arnprior, Ontario, reporting that it “may be as thick as 500 to the square foot, while in hollows and depressions in the snow—such as foot-prints—from which they cannot escape, they sometimes accumulate in solid masses that could be ladled out with a spoon.” James (1933) noted an assemblage of this species at Pottageville, Ontario, and reported that “beneath the hemlocks they covered the snow with a frequency of over 400 to the square foot.” A related species, tentatively identified as A. bengtssoni Agren, appeared in a population estimated by Park (1949) as exceeding 4,000,000 from three exit holes in an area of six square feet in Illinois in December, 1946.

The fulgorids of the genus Laccocera Van Duzee were revised by Penner (1945. J. Kansas Ent. Soc. 18: 30-46), who described and figured the seven species known to occur in North America. In all, five species are represented in the Canadian National Collection. One of these is previously undescribed, and three others have not been recorded from Canada previously. The following are a description of the new species and records of other Canadian species from specimens in the Collection.

In the writer's list of the Odonata of Ontario fifty species were recorded from the Kenora District of Ontario and only one from the Rainy River District. Thirty-five are reported from the vast northern part of the District known as the “Patricia Portion” and twenty-three from the southern part. The records from the Patricia portion are all from three widely separated localities but probably give a fair general picture of the odonate fauna of these northern latitudes. The records from the southern part of the District, on the other hand, are almost entirely from one locality, Minaki (approx. 50° N. Lat., 9° W. Long.) and are quite inadequate even for that one locality, some of the commonest regional species not being included.

Aside from M. acerbus (Jordan), which is apparently a breeding parasite of Tamias striatus (L.), a chipmunk, the holarctic genus Megabothris Jordan 1933 appears to be truly associated with the Microtinae, some of the species showing special affinities for particular species of these mice, others infesting several species, or even genera, within a geographical region.

The nearctic Megabothris asio (Baker) favours the common meadow vole, Microtus pennsylvanicus (Ord), and occurs throughout most of the range of that mouse. The writer recognizes two valid subspecies, M. asio asio, which is restricted to eastern North America, and M. asio megacolpus (Jordan), of western North America. The nominate race ranges from Labrador to Delaware. M. asio megacolpus (=M. asio orectus Jord.) ranges from western Quebec, western Ontario, and Michigan westward to the Coast Range, and from California north at least to the 60th parallel.

In British Columbia parathion was first officially recommended to the fruit grower in 1949 for the control of orchard insects and mites, particularly the pear psylla, Psylla pyricola Foerst.; the European red mite, Metatetranychus ulmi (Koch)=[Paratetranychus pilosus (C. & F.)]; and the Pacific mite, Tetranychus pacificus McG. Similar recommendations were made simultaneously in other Canadian fruit-growing areas. In British Columbia the Okanagan Spray Committee advised the use of only one formulation and one concentration: 15 per cent wettable powder at 0.75 pounds per 100 imperial gallons. At the start of the season most growers were rather reluctant to use parathion, not necessarily because it was new but because the poisonous nature of the material had been so thoroughly impressed upon them. However, as the season progressed and orchardpests became generally more troublesome, their attitude changed, so that by mid-season the use of parathion was common. It is estimated that at least 75 per cent of Okanagan Valley fruit growers used this insecticide at one time or another during the season. They bought from 40 to 50 tons of 15 per cent parathion wettable powder in 1949.

During the past four years Mr. Douglas C. Ferguson has collected dragonflies in Nova Scotia thereby greatly increasing our knowledge of the geographical distribution of these insects within the province. He very generously presented to the writer his entire collections comprising 327 specimens of 51 species, four of these being new records for the Maritime Provinces and two others being new for Nova Scotia. In the annotated list of species below these new records are indicated as follows: New records for the Maritime Provinces are indicated by a double asterisk (**). Records which are new for Nova Scotia only, are indicated by a single asterisk (*). A better representation of the widely distributed northern genus Somatochlora whould have been expected in a collection of this size made from the territory covered, in view of the fact that at least eight species are known to occur in thls territory. The reasons for their escaping capture is doubtless due, in part, to the restricted habitat occupied by many of the species, and in part to the difficulty of collecting specimens.

The search for compounds effective in the immunization of crop plants from insects or fungi has been prolonged and, with few exceptions, unsuccessful. It was not until the early 1940's that Kukenthal, in the routine testing of the biological activities of new compounds prepared by the I. G. Farbenindustrie A. G., observed that certain fluorine and phosphorus compounds synthesized by Schrader (1917), had this property and were described by Schrader as suitable for the “internal therapy” of plants. Because of the accepted application of the term therapeutant by Cunningham (1935) to toxicants in general, Shaw and the writer (1947) borrowed the term systemic (meaning that the plant as a whole is affected) to differentiate this type of action from the localized effect of previously known insecticides.

During field studies of the behaviour of larvae in colonies of Malacosoma disstria Hbn., it was observed that two species of ants, Camponotus herculeanus ligniperdus (Latr.) and Formica fusca L., were common on the twigs of the small trees, Populus tremuloides Michx., on which the caterpillars were established. Ant nests were common near the bases of trees, and the worker ants climbed the trunks and moved along the branches either to forage or to tend aphid colonies. When the tent caterpillars were small, they were frequently attacked by the ants. There were two distinct types of attack: one the result of foraging by worker ants and the other the result of defence of aphid colonies by the ants.

Among the attributes of the parasitic Hymenoptera that contribute to the ability of certain species to maintain host populations at low densities is the power to restrict egg deposition to sites suitable for the continued development of the offspring, and to regulate, regardless of host density, the number of eggs deposited per host (Flanders 1947). High searching capacity is, in part, a function of female longevity correlated with the conservation of reproductive material. It is self evident that time used in wasteful oviposition means less time for searching and consequently less effective control of the host.

Grasshoppers, tree crickets, and katydids always cause some injury to tobacco in southwestern Ontario, and at times the injury is very severe. Thc leaves may be riddled or even completely stripped, the most severe injury usually occurring late in the season, about harvest time. These insects breed in sod, in wood-lots, and along roadsides, and such areas require special attention when control measures are undertaken. Because it is usually considered advisable to restrict the amount of insecticide applied to tobacco leaves, the chlordane dust used in this experiment was applied only to the vegetation bordering the field. Any control by applying poison to tobacco plants can be effected only after at least limited feeding and some injury to the leaves; but treatment of field margins uses waste plans as the poison ‘carriers’ and a large part of the injury to tobacco is avoided. This method of control is useful only for insects which feed on general vegetation and would be of little value in controlling species which restrict their feeding to the cultivated crop.

The factors responsible for the relative resistance of plants to aphid attack are not very well known. Chemical analyses of several varieties of peas indicate that the quantity of nitrogenous constituents in plant juice is proportional to the susceptibility of the plant to aphid attack. These tests hare also demonstrated that amino acids represent the major portion of the soluble nitrogenous constituents in the plants studied.

By the method of paper partition chromatography, several qualitative and semi-quantitative analyses were made of the amino acids in juice extracts of two varieties of peas and of pea aphids feeding on these varieties. This particular method of chromatography, first developed in England in 1944 by Consden, Gordon, and Martin (1), and modified since by other workers (2, 3), was found very effecrive for these studies.