The usefulness of radioactive isotopes as tracers in studies of insect biology has been demonstrated on a number of occasions during the past few years. Tracer techniques have made possible the collection of accurate data on the dispersal and flight range of insects (2), and other specific behaviour traits which would otherwise be difficult or impossible to determine (1).

It is a commonplace entomological observation that each phytophagous insect is restricted in its feeding to a small fraction only of the plant species that grow in any area. This phenomenon is generally referred to as “host selection”. The ecological significance of host plant selection among insects is manifest principally in an effect on the geographical distribution of insect species since phytophagous insects can occur only where suitable host plants are available.

Some of the results of an attempt to apply ecological principles in the solution of apple insect control problems in Nova Scotia have been given in previous papers by Pickett et al. (1946), Lord (1947, 1949), Pickett (1952), and MacPhee (1952). Briefly, these studies aim at an understanding of the changes in the interrelations of the species in an orcl-lard when spray materials are added to the environment. The emphasis to date has heen placed on the effects of spray chemicals on the populations of entomophagous species. The results of this work have already had a marked effect on orchard insect control practices in Nova Scotia.

During the summer of 1916, a few specimens of a tortricid were submitted to Ottawa for identification. The larvae were abundant on cabbage leaves in the vicinity of St. John's, Newfoundland. At that time the insects were not definitely identified as a European species and were described as new by A. Gibson, who proposed the name Tortrix oleraceana Gibs. (1916. Can. Ent. 48: 373). Some time ago it was realized that oleraceana belonged to the genus Cnephasia. After additional material was received recently from Mr. A. H. Butler, St. John's, Newfoundland, comparison with European specimens in the collection of Dr. B. P. Beirne showed that the species in question is Cnephasia virgaureana Treit.

Within the next few years those of us who have been directly concerned with the first appearance of termites in the Province of Ontario will either have forgotten some of the earlier details of this introduction or wiil have passed beyond the field of such earthly considerations. The present paper has been wrinen so that those who mav be interested in the earlv history of the introduction of termites into Ontario in the years that lie ahead wll have at least one authoritative paper upon which to hase their studies or investigations.

Studies of the goldenrod gall caused by Eurosta solidaginis Fitch have been made by various authors who reared insects from the galls in North America, e.g. Hughes (1934), Milne (1940) and Ping (1915). Snyder (1898) described the emergence of an adult fly from a gall in Illinois. In Canada, insects have been reared from galls collected in Manitoba and the Northwest Territories by Brodie (1892), in Quebec by Fyles (1894) and in Ontario by Harrington (1895). An opportunity has been taken recently to examine specimens reared by Dr. G. Beall from galls collected at Chatham, Ontario in 1930 and to rear insects from galls in the vicinity of London, Ontario.

The forest tent caterpillar, Malacosoma disstria Hbn., and the eastern and western tent caterpillars, M. americanum (Fab.) and M. pluviale (Dyar), are common pests of several species of deciduous trees in Canada. All are colonial during the larval stage, but M. disstria differs from the others in one respect: it does not construct a communal tent. This difference in habit merits special consideration in any comparative study of larval behaviour, particularly in one concerned with the effects of physical factors upon the insects, since a tent modifies the effects of the physical environment considerably. Recently, a series of such studies was carried out, and one part of the work consisted of laboratory and field observations on the light reactions of larvae. The results obtained have raised a number of new questions which unfortunately cannot be answered now, hecause two of the species have been difficult to obtain in quantity since 1950. Nevertheless, the findings are presented here without additional delay, since they are of general interest, and other workers may wish to use them.

Franklin (1913) (p. 448) stated, “There is not vet a single new world account of a Psithyrus having been found in a Bombus nest”. Since then, of the seven North American species, four have been reported found in nests of Bombus spp. by Sladen (1915), Frison (1916, 1921, 1926), Plath (1934), Linsley (1944), and Leech (1947). Of these records only two are from Canada, both being from British Columbia. Sladen (1915) reported finding the well-preserved body of a female of Psithyrus insularis (Sm.) and several cocoons, from one of which he extracted a male of P. insularis, in a nest containing an old queen and several workers of Bombus flavifrons Cress. Leech (1947) found a P. insularis female in a nest containing several workers of Bombus mixtus Cress., and concluded that the iniquiline had supplanted the mixtus queen.