The following list of hymenopterous parasites of Choristoneura pinus Free. is based on an analysis of two collections that the writer recently received through the kindness of Dr. T. N. Freeman. The first collection consisted of 116 mature larvae and pupae of C. pinus taken by Dr. Freeman at Normandale (Norfolk Co.), Ont., early in July, 1951, in a plantation of Pinus banksiana Lamb. Rearings from this lot, at Ottawa, by Dr. Freeman and the writer yielded 48 moths and 41 specimens of parasites, the latter comprising 10 species. There was a pupal mortality of 27 specimens. The second collection consisted of 75 adult parasites that were reared at Ottawa by Dr. Freeman from a lot of 456 pupae of C. pinus taken by Mr. V. Hildahl at Beauséjour, Man., during July, 1951, on P. banksiana. There were five species of parasites in this collection, three of which are not represented in the Normandale material.

From 1945 to 1949 tests were conducted at Ottawa to determine whether certain of the more commonly grown commercial varieties of onions are resistant to the onion maggot, Hylemya antiqua (Meig.). Sleesman (1934), from the results of field tests in Ohio, had concluded that some varieties of onions do support significantly higher populations of the maggot than others.

In 1945 and 1946 at Ottawa, 17 varieties of onions were tested; in 1947, 1948, and 1949 the number was reduced to nine, which are listed in Table I.

The tuber flea beetle, Epitrix tubrnis Gent., has been a pest of potatoes in the Fraser Valley and the lower mainland of British Columbia since 1940 (Glendenning, 1942); However, it was first reported from the interior in 1944, at Keremeos and Princeton and in the southern Okanagan Valley (Buckell, 1944). In 1945 and 1946, the first surveys were made to determine the area involved. The area and the degree of infestation have since increased anti1 it is now a very serious pest in the interior. The area of infestation is bounded by the International Border on the south and the Okanagan Valley on the east and extends northward to Malakwa. From here the line runs west through Adam's Lake to Barriere, to Criss Creek, to Pavillion, thence south to Lillooet, Lytton, Merritt, Princeton, and Hedley.

Musca domestica L., the house fly, has hitherto been the only species of the genus definitely known to occur in North America. West (1951) wrote: “This paucity of species in the New World is somewhat strange…it would not be surprising if one or more additional representatives of the genus Musca should sooner or later put in their appearance on the American scene.” An authentic record of a second species, M. autumnalis Deg. [=M. corvina Fab.], is therefore of considerable interest.

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.

It is unfortunate that Frick (1952), in preparing his generic revision of the Agromyzidae, was unable to examine the types of many species described by Loew, Malloch, Frost, and others. In such circumstances, a few mistakes were bound to be made, and the fact that these are not more plentiful is a tribute both to the quality of the descriptions of the authors concerned, especially Malloch, and to the care with which these descriptions have been analysed. In 1949, being interested in the possibility of using Hendel's (1931) European classification for the North American fauna, I examined 71 of the types in question, and was able without difficulty to reconcile most of them wiih Hendel's generic and subgeneric concepts. Of these types, only 13 are now found to conflict with the assignment proposed for the species by Frick.

Internal parasites belonging to the genus Scelio Latr. have been reported found in grasshopper eggs in several of the northern states of the United States. Muesebeck and Walkley (1951, p. 702) reported S. calopteni Riley in Melanoplus spp., including M. mexicanus mexicanus (Sauss.) and M. bivittatus (Say), in states adjacent to thc Prairie Provinces of Canada. In Canada, Criddle (1921) reported Scelio sp(p). in Manitoba during a grasshopper outbreak which took place about 1920. Since then, the presence of Scelio sp(p). in grasshopper eggs has frequently been noted in the Prairie Provinces by entomologists. Studies of the viability, embryonic development, and parasitism of Western Canadian grasshopper eggs begun and largely carried out by the late Mr. H. W. Moore at the Field Crop Insect laboratories at Brandon and Saskatoon have made possible an approach to the quantitative evaluation of these parasites.

Lord (1949) listed the predators of the European red mite, Metatetranychus ulmi (Koch.), in Nova Scotia and described the effects of a number of chemicals on them. Among the more important predators is the thrips Haplothrips faurei Hood. This thrips, however, does not confine its feeding to European red mite eggs but readily attacks the eggs of many other mites and insects. There is strong evidence that it is one of the most important biotic factors in the natural control of insect and mite pests in Nova Scotia apple orchards. It and another species, Leptothrips mali (Fitch), are the only thrips of economic significance, and H. faurei, because of its greater numbers, is the more important. A description of the life-history of L. mali was given by Bailey (1940), who also (1939) studied the biology of another thrips, Scolothrips sexmaculatus (Perg.), which is of minor importance in Nova Scotia. The only other predacious thrips found is a species bclieved to be Zygothrips minutus Uzel, which occurs only rarely and in small numbers. Haplothrips subtilissimus Hal. (later identified as H. faurei), was found by Putman (1942) in Ontario to be predacious on phytophagons mites and the eggs of oriental fruit moth, Grapholitha molesta Busck.

Since 1934, when studies of aphids infesting potatoes were begun in New Brunswick, it has been observed that a large number of potato aphids are attacked by parasices each season. More attention was given to parasitized aphids in 1950 than in previous years, in a study of parasitism as a factor in aphid control. In this paper are recorded the parasites reared from aphids collected on potatoes and other hosts in New Brunswick in 1950.

Many attempts have been made to overcome the difficulties attendant upon storing insect material over extended periods of time in small vials of alcohol. Cork stoppers fail to meet requirements for various reasons, while their substitution with rubber ones may introduce still further complications. Both are liable to shrink or to swell while either may be forced out of the vials as a result of variations in room temperature. In addition, neither can be readily marked in such a manner that the contents of the vials are permanently and plainly legible from above.

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.

Alate Viviparous Female: Body, legs, antennae, and cornicles bearing moderately long setae, but not conspicuously hairy. In cleared specimens, the following parts are dusky brown: head, thorax, cornicles, cauda, coxae, rostrum and bases of the femora; a very short basal portion, and the distal half of the tibiae; tarsi; antennal joints I, II, VI, and distal portions of III, IV and V. As in many other species in this genus, there are four longitudinal rows of small brown spots dorsally on the abdomen, extending from the thorax to the area between the cornicles, and two rows laterally, one on each side, composed of somewhat larger brown areas around the spiracles. Remainder of body and appendages clear. Wings hyaline, with media faint and twice-branched. Antennal sensoria, III 5(4-6); IV(1-2); V 2. Ocular tubercles present.

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.

There is ample evidence that many plants overwintering in cold regions undergo a hardening process in the fall that enables them to survive lower temperatures than they otherwise could (Levitt, 1941). It is generally assumed by entomologists that a similar acquisition of cold hardiness protects those insects that require it. It is the purpose of this paper to examine the evidence that insects develop cold hardiness, and to present new evidence regarding its acquisition and loss.

Studies on the ecology of the fauna of apple orchards in Nova Scotia were initiated in 1943, to determine the long-term influence of spray chemicals on the populations of apple-infesting insects. At that time it was felt that the indiscriminate use of spray chemicals in the control of orchard pests was sometimes creating worse problems than those corrected–and was threatening the economy of apple production; and that there was an urgent need to determine, if possible, how to harmonize biological and chemical control. A more comprehensive discussion on the biological and philosophical concepts on which the studies were based may be found elsewhere (Pickett et al., 1946; Pickett, 1949a; 1949b).

Bugher and Taylor (1949) and Hassett and Jenkins (1949) reared highly radio-active adults of Aedes aegypti (L.) from larvae kept in a solution of radioactive phosphorus. Jenkins and Hassett (1949) obtained radio-active adults of Aedes pullatus (Coq.) and Aedes excrucians (Wlk.) with an average radio-activity of 4,300 counts per minute by rearing larvae in ponds to which radio-active phosphorus was added. Jenkins and Hassett (1951), with sub-Arctic mosquitoes, chiefly Aedes communis (Deg.), produced adults with radio-activity from 100 to 3,770 counts per minute from larvae reared in vats of P32 solution; adults released and recaptured in the field had an average radio-activity of 915 counts per minute. Thurman and Husband (1951) tagged larvae with P32 and released 400,000 adult mosquitoes in California. Of this number, 249 adults were recaptured at distances up to 1⅞ mi. downwind and 1½ mi. upwind from the release point. Yates et al. (1951) and Hassett and Jenkins (1951) produced radio-active adults of Aedes sticticus (Meig.) and Aedes aegypti (L.) by allowing them to feed on P32 solutions; the radio-activity was readily detectable with a Geiger counter for as long 13 days.