The following descriptions of new species of black flies are based on material acquired from several sources in the Division of Entomology. The largest collections were made by field parties engaged in the Northern Insect Survey, a project commenced in 1947 and conducted by the Division in co-operation with the National Defence Research Board. Much of the simuliid material accumulated by this survey still remains to he examined and it will be several years before the valuable data on species distribution that it contains can be assembled into a form suitable for publication. Several collections of northern material have also been contributed by officers of the Household and Medical Entomology Unit. The rest of the material is the outcome of rnp own field studies in the Ottawa district, These studies, comnenced in 1949 and still continuing, are on a much smaller scale than the northern work and are designed chiefly to increase my knowledge of the group and to verify or supplement certain aspects of the work done by Twinn (1) in this area.

For many years the true members of the illibalis group (usually placed in the wastebasket genus Pyrausta) have been listed as two or three species, under the names gracilalis Hulst, illibalis Hübner, and arsalteulis Walker. I was considerably surprised, therefore, to find several additional species standing, for the most part unrecognized, in North American collections. A further species, haedulalis Hulst, was compared by its author to gracilalis, and was placed by McDunnough (1939) between gracilalis and illibalis; I have seen the badly damaged tvpe of haedulalis in the collection of Rutgers University, and am convinced ihat the species does not belong in the present group.

I believe that in the main insect surveys have been initiated each because of some definite need. In the case of surveys of pest species, such as the chinch bug, corn borer, or budworms, the need has been the necessity of obtaining accurate knowledge of population densities and areas of infestation, this to serve as a basis for predicting economic losses or extent of needed control operations.

In most instances general faunistic surveys have had a more roundabout motivation. This kind of a surrey usually starts out as an identification service, its aim to tell whether or not suspected insects are injurious or beneficial, and if injurious, how much so, and what is known regarding the control of the species. Here again the desire to predict is uppermost in our mind, as with the case of pest surveys. Difficulties always arise in distinguishing injurious from closely related non-injurious forms, or in being sure how many kinds of insects are involved in one groop or another. In attempting to solve these problems we gradually arrive at the point where we want to know how many kinds of all insects there are in a region, and how to tell them apart.

Leconte's sawfly or the red-headed pine sawfly (Neodiprion lecontei Fitch) is a common insect attacking pines in Ontario. Plantations red pine are almost invariably attacked from the time the trees have reached two to four feet in height. Periodically epidemic populations cause significant damage. The life history and habits of the species have heen described by Middleton (2) who states that this insect attacks practically all species of pine as bell as larch. Schaffner (3) also indicates that the larvae feed on a wide variety of pine and occasionally on other conifers. Red pine (Pinus resinosa Ait.) is undoubtedly the usual host, although in Ontario jack pine (Pinus banksiana Lamb.) is sometimes attacked. In 1946 evidence was secured to show that jack pine needles may be selected for oviposition even in an area where red pine foliage is plentiful. (Figure 1).

The use of potassium hydroxide solutions for clearing minute insect specimens, or portions of large ones, is a well-known and widely used procedure. Extreme care, however, is necessary to provide rapidly the exact degree of transparency in the subject. To provide for these requirements an economical heater was designed to warm a micro-culture slide bearing a few drops of clearing solution. The specimen is immersed in the cold solution on the slide, and the slide is then placed on the heater. The requisite amount of current is supplied to the heating element and clearing of the specimen to the exact degree desired can be obtained in a short time while the process is observed through a binocular dissecting microscope.