Observations on the biology of Trybliographa rapae (Westw.) were made as part of a general study, in Canada and Europe, of the biotic factors acting against the maggots of Hylemya brassicae (Bouché), H. floralis (Fall.) [H. crucifera Huck.], and H. cilicrura (Rond.) that attack cruciferous crops. During the study many thousands of host insects from both Canada and Europe were examined and large numbers of both hosts and parasites were reared in the laboratory.

Twelve species of sawflies are common on white birch (Betula papyrifera Marsh.) in the forested areas of Manitoba and Saskatchewan. They also occur in Fastern Canada and the United States. A key is presented at the end of the paper by which the late instars of these twelve species can be identified. The immature forms of these species were described by Dyar (1893, 1895a, 1895b, 1895c), Middleton (1915, 1922) and Riley (1890). Unfortunately these descriptions are scattered in several publications, and in most cases the names of the genera or species in the original descriptions have been changed (Ross 1951). This paper brings together the current nomenclature and some biological information on these species.

The following technique employed at the Vernon Laboratory greatly facilitates the preparation of inflated larval specimens. Inflated larvae are dried over a reflector infra-red heat lamp (250 watts), clamped to a titration stand. The standard heat lamp with an aluminum reflector, and the red bowl heat lamp with a nickel reflector have been tested; the latter is preferable because it radiates more heat with reduced glare.

It has been shown by Farstad (1940) and Platt (1946, 1948) that resistance in wheat to the wheat stem sawfly, Cephus cinctus Nort., is positively correlated with solidness of stem. Under certain environmental conditions the resistant variety Rescue becomes susceptible to sawfly damage. The nature of this resistance is unknown, but a study of the nutritional requirements of C. cinctus may reveal it and perhaps assist in the development of new resistant varieties. The preliminary phases of this project were conducted with the following objectives: to studv the anatomy of the larval organs of ingestion and digestion; to determine the plant tissues ingested by the larva; and to study the hydrolytic enzymes present in feeding larvae.

In collecting sawfly eggs, larvae, and cocoons for propagating beneficial insects at the Belleville laboratory, a heavy infestation of a pine sawfly, Neodiprion nanulus Schedl, was discovered in 1942 nine miles north of Belleville, on a 25-year-old plantation of red pine, Pinus resinosa Ait.; Scots pine, Pinus sylvestris L.; and jack pine, Pinus banksiana Lamb.

From samples of the eggs collected in the spring of 1943, no parasites emerged.

Wood (1951) published a list of lepidopterous larvae collected from commercial blueberry fields in Charlotte County. N.B. Among the species consistently collected annually from 1947 to 1952 are the cutworms Spaelotis clandestina (Harr.) and Polia purpurissata (Grt.). Although notes on both species have been given by various authors, including Crumb (1929, 1932), Gibson (1915), and Phipps (19301, no complete account of their life-histories has been published.

In the spring, spruce budworm (Choristoneura fumiferana (Clem)), emerge as second-instar larvae from hibernacula. This emergence may be sudden and is readily detectable in the field. In northwestern Ontario, the sudden appearance of larvae in large numbers was especially spectacular in 1948; that year, very few insects were observed on May 11, but on the following two days, countless larvae could be seen on strands of silk streaming out from trees. Many of the insects were carried away by air currents. The surface of Big Canon Lake, a body of water close to four square miles in area, was covered with larvae, at an estimated density of 100 larvae per square foot of surface. At other times, however, emergence may be gradual or there may be two distinct periods of abundant emergence. Furthermore, the time of abundant larval emergence through six years has varied by as much as four weeks. Because of such differences, prevailing spring temperatures were examined to determine what relationship might exist between temperature and the time and character of emergence. This paper points out a relationship between emergence and April and May temperatures, and an apparent temperature threshold for emergence.

Investigations at Fredericton requiring specific instars of the cabbage maggot, Hylemya brassicae (Bouché), led to studies of laboratory methods for rearing this insect. Previous attempts to rear H. brassicae had proved unsuccessful since the species does not reproduce readily under artificial conditions. Slingerland (1894) was unable to obtain eggs of this species, though his cages contained hundreds of adults. Washburn (1906) reported that adults that had matured in the field would oviposit in cages. Schoene (1916) used adults that had emerged in the laboratory as well as some fresh-looking individuals captured at large. These were supplied with water and some cruciferous plants, as well as banana, sugar, water, and blossoms of weeds common in his community. Adults fed readily upon the sweetened mixture and decaying banana, and lived four to eight weeks. One female was dissected and found to contain 13 full-sized eggs, but no reference to oviposition was made.

Numerous reports have been received from growers in Manitoba and Saskatchewan that the sweetclover weevil, Sitona cylindricollis Fahr., greatly reduces sweet clover seed yields by feeding on the seed or by causing it to drop. It is known that weevil populations are often very high in clover fields that are left for seed. To determine the amount of damage that might be caused to seed by the weevil, a number of tests were conducted in 1951 and 1952.

The possible uses of the serological precipitin test for investigating certain entomological problems have been reported previously by West (6). It was suggested that the precipitin test offered a new tool which together with such tools as the electron microscope, paper chromatography and radioisotopes would contribute materially to future advancement in entomology. It is evident to everyone that progress in many branches of entomology is being made currently by the use of new and improved procedures.

Maggots of Pegohylemyia sp. have been found inhabiting the cones of white spruce, Picea glauca (Moench.) Voss, in southern Ontario. The species was identified from a single male specimen as probably Pegohylemyia anthracina Czerny by the Swedish authority Dr. O. Ringdahl. Difficulty in rearing the maggots to the adult stage has delayed confirmation of this identification but it is expected that a good series of adults will be available shortly. In this paper, however, the emphasis is placed on the instars with an outline of the life cycle. It is shown that the second- and third-instar larvae are free-living, but the first-instar larvae moult to the second within the egg chorion.

In studying populations of wood-boring beetles in dead trees or logs, it is usually the larval form with which the worker must deal. The various species have different habits and although they may be present in very large numbers, some may do no direct damage to the wood. For any estimate of the existing damage-potential, larval identification is therefore an obvious prerequisite. During recent studies of wood-boring beetles in fire-killed pine in northern Ontario, the larva of Acmaeops proteus was by far the most common encountered, but its identity remained uncertain until a programme of rearing larvae from known adults was carried out. The apparent absence of a published larval description of this, one of the most common cerambycids in our eastern coniferous forests, has prompted the preparation of this brief description.