The widespread presence of the pitch nodule maker in pine plantations and jack-pine regeneration in Manitoba and Saskatchewan stimulated this investigation. Although this insect is not causing serious damage at present it could become a problem should the area of pine plantations be increased in Manitoba and Saskatchewan.

When Manns (1939) reported that the meadow spittlebug, Philaenus leucophthalmus (L.), was a vector of peach yellows, the investigations on the bionomics of vectors of peach virus diseases then being carried on in the Niagara Peninsula were expanded to include this species. During the rearing of large numbers of nymphs to determine the host plants and habitats of P. leucophthalmus some other species of cercopids were also encountered.

The biology of Bracon cephi (Gah.) (Hymenoptera: Braconidae) was described recently (Nelson and Farstad, 1953). During studies from the Field Crop Insect Laboratory, Lethbridge, on the biology of this important parasit, observations were made on various other hymenopterous parasites associated with the wheat stem sawfly, Cephus cinctus Nort. The parasites discussed herein are Eupelmella vesicularis (Retz.) (Eupelmidae), Eurytoma atripes Gah. (Eurytomidae), and Merisus febriculosus Gir. (Pteromalidae). These three parasites have been noted by Gahan (1933) as parasites of the hessian fly, Phytophaga destructor (Say).

During studies of the parasite complex of the diamondback moth, Plutella maculipennis Curt., at Ottawa, Ontario, July to October, 1952, and April, 1953, 1,234 host cocoons were collected from a heavily infested field of Penn State Ballhead cabbage. On October 31, eight adults (2 ♂ and 6 ♀) of Tetrastichus sokolowskii Kurdj., emerged from a single cocoon collected 16 days previously and held under laboratory conditions in a gelatin capsule. On May 10, nine adults (1 ♂ and 8 ♀) and on May 15, eight adults (1 ♂ and 7 ♀) of the same species emerged from two overwintered cocoons collected 14 and 16 days previously. In each case, the lack of parasitic remnants indicated that they were primary parasites.

While rearing Galleria mellonella L. to further studies by Mankiewicz (1952) on the wax splitting enzymes which they produce and the action of these enzymes on Myctobacterium tuberculosis, it proved difficult to secure a constant supply of honey and comb, the natural food and habitat of this species. Haydak's (1936) summary of earlier work on rearing this wax moth indicated that success had been attained with several artificial media. The writers, therefore, tried an artificial medium and attempted to assess its effect on the nature of the enzymes later extracted from the larvae.

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.

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.

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.

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.