There are five known species of the genus Hylobius in North America. These are H. congener Dalla Torre, Schenkling and Marshall, H. pales (Herbst), H. radicis Buchanan, H. pinicola (Couper) and H. warreni Wood. Buchanan (1934) recognized the first three species and indicated that “there might be one or two additional races or species”. He also stated, “Hypomolyx piceus Deg. is placed in Hylobius in the Junk catalog; it differs from the above 3 in its untoothed femora.” Wood (1957) recognized H. pinicola (Couper), invalidated the generic name Hypomolyx, and erected a new species, Hylobius warreni. He briefly described the new species and presented a taxonomic key by which it could be distinguished from H. pinicola and a Eurasian species, H. piceus (DeGeer). It is now clear that Hypomolyx piceus as referred to by Warren (1956a, 1956b) actually consisted of two species, Hylobius pinicola and H. warreni.

Orgilus obscurator (Nees) (Braconidae) and Temelucha interruptor (Grav.) (Ichneumonidae), parasites of the European pine shoot moth, Rhyacionia buoliana (Schiff.), were imported from Europe and released in Waterloo County Reforestation Area, near Elmira, Ontario, from 1955 to 1959.

O. obscurator is the only braconid of known economic importance as a parasite of the shoot moth in Europe (Thorpe, 1930). Recent importations showed that it is also the most abundant parasite of this host throughout Europe. The species was first imported from England in 1928, but was present in Canada earlier (Watson and Arthur, 1959) which suggests an earlier accidental introduction with the host. A total of 8,878 adults were released in Ontario in 1928 to 1949 (Coppel and Arthur, 1954) and 7,912 in 1955 to 1959.

The sawfly Neodiprion swainei Midd. has long been recognized as a serious defoliator of jack pine, Pinus banksiana Lamb., but it was not until the relatively recent use of jack pine as a raw material for pulp that interest in the sawfly became acute. Subsequently, investigations into the natural control of N. swainei were begun in the year 1955 near the headwaters of the Gatineau River, P.Q. (47° 55′ N., 75° 25′ W.) which was considered to be near the centre of the current infestation.

Larvae of Aletia oxygala luteopallens (Sm.) found on chicory (Cichorium intybus L.) in Quebec City in May, 1958, were infested with a nuclear polyhedrosis virus and with a microsporidian. Larvae suffering from polyhedrosis leave the interior of the stems, die, and remain hanging in a characteristic way “glued” to the exterior of stems. The diagnosis of the polyhedrosis virus was confirmed by Dr. G. H. Bergold at the Insect Pathology Research Institute at Sault Ste. Marie, Ontario, and that of the microsporidian by Dr. H. M. Thomson of the same Institute. Neither microorganism had ever been noticed before.

It was of interest but no great concern when the finding of Musca autumnalis DeGeer in Nova Scotia was reported by Vockeroth (1953). Previously, M. domestica Linnaeus was thought to be the only species of the genus present in North America. Two previous reports of M. autumnalis as corvina (Walker, 1849, 1871) were thought to be misidentifications.

There seems to be only one report of the aphid Myzus certus (Wlk.) transmitting a virus, bean yellow mosaic virus (Swenson, 1957). It is therefore noteworthy that M. certus transmits potato virus Y as readily as does Myzus persicae (Sulz.), until now the most efficient vector known for virus Y. In one experiment that showed this, the numbers of single aphids out of 50 that transmitted virus Y were 27 and 28 respectively. Briefly the experiment was as follows: M. certus was reared on pansy (Viola tricolor) and M. persicae on rape (Brassica napus); the strain of virus Y was the one that has been used at our laboratory for aphid transmission studies during the past ten years; single adult apterae or late instar nymphs each probed once for less than a minute into an infected tobacco plant and then fed overnight on a young healthy tobacco plant (Nicotiana tabacum var. White Burley).

Many attempts to establish introduced parasites in Canada failed though the climatic conditions at their release points were apparently similar to those of their native habitats (Thorpe, 1930; Baird et al., 1947). It is known that many adults of hymenopterous parasites feed on flowers, aphid honeydew, host body fluids, and other substances (Jackson, 19 37; Thorpe and Caudle: 1938; Schneider, 1939; Györfi, 1945, 1951; Zoebelein, 1956). This brings up the possibility that nourishment from one or more of the above sources is necessary for surviial and reproduction, and that some of the failures may have been because of the absence or scarcity of suitable adult food (Clausen. 1956). At present data on the food preferences of adult hymenopterous parasites are scarce. Except for a few field and laboratory observations, there are no experiments that demonstrate distinct preferences for one food over another. The results of the experiments described in the present paper demonstrate that adults of the species studied have preferences for some flowers and food substances tested.

Infestations of Profenusa thomsoni (Konow) have occurred throughout most of northeastern, central, and southern Ontario since 1948 (Sippell, MacDonald, and Wallace, 1956), but before 1955 (Lindquist, 1955), its presence was not recognized because it was confused with the common birch leaf miner, Fenusa pusilla (Lep.).

A spruce budworm outbreak started in Quebec and adjoining parts of New Brunswick in 1949 and spread each year until by 1955 most balsam fir stands within an area of 32,000 square miles were attacked. Approximately 45 per cent of this area was in the Lower St. Lawrence and Gaspe regions of Quebec. In Quebec, important population reductions took place in various sectors of the outbreak area as a result of unfavourable weather conditions in 1956 and 1957 (Blais, 1958a, 1958b), and the final collapse occurred in 1958 when populations returned to the endemic level throughout the area (Blais and Martineau, 1958). In New Brunswick, a relatively small outbreak area remained at the end of the summer in 1958 (Webb et al., 1959). The large-scale aerial applications of DDT begun in New Brunswick in 1952, and in Quebec in 1954, were continued until 1958. Biological studies in connection with the spraying were carried out in both provinces. In Quebec these studies consisted of assessing spruce budworm population fluctuations in both sprayed and unsprayed areas and in determining, where possible, the causes for these fluctuations. All factors associated with changes in population could not be adequately measured over such a large territory, but a real attempt was made to obtain information on parasitism. The present paper deals with this aspect of the studies.

The immature stages and adults of Chaoborus borealis Cook were collected near Churchill, Manitoba, in 1949 and 1950 in investigations on the natural control of biting flies (James, 1953; James and Smith, 1958). Cook (1956) described the adult and the fourth-instar larva in his revision of the Nearctic Chaoborinae, and noted the similarity between the fourth-instar larva and that of C. flavicans (Mg.). This paper contains descriptions of the egg, the first-, second-, and fourth-instar larvae, and the pupa of C. borealis.