In nutritional studies the proper evaluation of the results depends upon the manifestations of deficiencies. It is essential, therefore, to control all the factors which enter into the nutritional functions of the organism under study. In order to do this, the intervention of symbiotic organisms should be avoided if possible and diets of known chemical entities should be formulated with the ingredients combined in known quantities. Using the cockroach, Blattella germanica (L.), the first condition can be approached, inasmuch as cockroaches can be made aseptic by freeing them from the fauna and flora of their intestinal tract and of their environment following the method described by House and Patton (1949). In the present study the second difficulty has been overcome by using diets formulated especially for this species, among the most important of which is a chemically defined food consisting of known quantities of amino acids, carbohydrates, vitamins, sterols and minerals.

In a paper published during the war Reeks pointed out that the sawfly which has caused much damage in the forests of Canada for about twenty years is identical with Lophyrus hercyniae, described by Hartig in 1837. In the same work he proved that Hartig was correct in describing hercyniae as a species distinct from Lophyrus polytomus Htg. Enslin's view that the two species should be united under the name polytomus is quite wrong. Reeks has shown that important biological and anatomical differences exist between them. Benson erected the genus Gilpinia for the species polytomus and for allied species. Reeks was unable to examine the types of the two species, kept in the Hartig collection in Germany, and for that reason he sent to me some specimens of the “European spruce sawfly” from Canada, with the request that I compare them with the types in the Hartig collection. The results of my examination are as follows.

In a preliminary paper on the role of small mammals in the natural control of the European spruce sawfly, Gilpinia hercyniae (Htg.), the writer (7) recorded that shrews have a remarkable ability to select sound cocoons in preference to those which are dead or emptied by parasites. This ability was said to be much less apparent, however, in the rodents. However, various experimental aspects of the project on natural control were not completed. This was due mainly to the severe decimation of the sawfly resulting from the combined attacks of small mammals, disease, and parasites. Since the above statements have elicited some interest, it secms worthwhile to present the data on which they were based. Other aspects of the project, particularly those concerned with the populations of small mammals and their relation to forest site, and with the role of larval Elateridae, will be reported later.

A general requirement of most biological research laboratories is suitable compact storage space for microscope slides. This is particularly true where space is required for storing deeper preparations such as whole mounts in a horizontal plane with their identification labels in full view. Of the many commercial cabinets now available few appear to be entirely satisfactory. Although some are constructed to hold the slides horizontally, in these the slide holders are in the form of trays with a capacity of not more than one dozen slides and the trays are carried in grooves nne above the other. In others, thin drawers are used in which the slides are laid side bv side on the bottom. In the former, considerable handling is required to expose the labels of the slides. In the latter, slides easily become disarranged, and are exposed to an accumulation of dust; and though considerable space is required, the capacity of the drawers in most cases is limited to less than 100 slides. A cabinet in which a number of desirable features is incorporated has recently been developed at this laboratory, and a description of it constitutes the basis of the present paper.

Lygus campestris (L.) was a major contributing factor in a disastrous reduction of carrot seed yields in the district of Grand Forks, B.C., during 1947 and 1948.

Knight (1941) lists this species as “common in the northern states and Canada; Holarctic in distribution”. Of its food plants he reports: “Poison hemlock (Conium maculatum) and other plants of the family Umbelliferae; Illinois specimens have been collected on wild parsnip (Pastinaca sativa) and cow parsnip (Heracleum lanatum). Reported in Massachusetts and New Brunswick as a pest on celery plants”.

The following list contains eighty-six species of spiders collected in the Mackenzie District. The greater portion of species were collected in the vicinity of Great Slave Lake; however, a few of these were from Fort Smith, close to the southern boundary of the Mackenzie District, and Great Bear Lake.

The collection was made during the summers of 1945, '46 and '47. The major portion of the collection was due to the efforts of Dr. D. S. Rawson, Department of Biology, University of Saskatchewan; Dr. J. G. Oughton, formerly of the Royal Ontario Museum of Zoology, Mr. J. R. Vockeroth of the University of Saskatchewan, and Dr. W. A. Kennedy, of the Biological Board of Canada.

It is a well known fact that the flight of moths and some other insects is affected by barometric pressure, but it is not well known how this phenomenon affects other insect activity. In a study of the ecology of insects in vegetable gardens at Brandon, Man., in 1948, the relationship of barometric pressure to insect activity was recorded.

It was noted in the field that the imported cabbageworm adults behaved differently under varying weather conditions. During warm, clear days they did little but move about freely and feed, but on days that were overcast, particularly preceding rain, they became active about the plants and appeared to be engaged mainly in egg laying.