In Canada surveys of mosquito populations have been conducted on a scale varying from country-wide programmes to local sunreys about centres of population. The work of the Defence Research Roard and Department of Agriculture in conducting surveys and biological snidies of mosquitoes across northern Canada has been reviewed by Twinn (1950, 1952) and Freeman (1952). During 1944 a country-wide survey, particularly of anopheline species, was conducted as part of a study of possible transmission of malaria (Twinn, 1944). In the Fraser River Valley Hearle (1026) studied the distribution and biology of the mosquitoes of that region. Surveys of a local nature around centres of population have been conducted by McLintock (1944) at Winnipeg, by Urquhart (1948) at Toronto and by Judd (1950) at Hamilton as a basis for control programmes at these centres. During 1952 such a survay, the subject of this paper, was carried out at London, Ontario and its vicinity to determine what species were present in the region, the times of occurrence of larvae and pupae in pools and the seasonal abundance of adults of each species.

Examination of the types of some species of Aedes has shown that a number of them have been misidentified by later workers. Certain changes of names are unfortunately necessary; these are indicated below. Notes on a few types not involved in this synonymy are included. Descriptions of two new species are also given–one of these has been frequently recorded and described in the literature under the name Aedes impiger (walk.); the other has not previously been described.

In preparing a revision of the triaspidine genera which occur in North America, the author has considered all the genera of this group from the world, and has found some shifting of species necessary. The genus Foersterin was created in 1896 by Szépligeti for the reception of two new species described from Europe. At that time, both the genus and the two included species were rather inadequately characterized. This situation has continued to the present day and several authors have incorrectly placed several new species from other zoogeographical regions in this genus. This paper is an attempt to clarify the concept of Szépligeti's genus, and gives a redescription of F. laeviuscula Szépl.

Insects of the genus Ceuthophilus although widely distributed in North America are seldom encountered by the collector unless attracted and captured by means of Hubbell's molasses traps. These traps, which consist of glass jars (Hubbell recommends pint-size Mason jars) containing half an inch to an inch of molasses diluted one-half with water, are buried to the brim in the ground or heaped around with stones, leaves, etc., to give access to the edge of the jar. Hubbell recommends placing them “…at least ten feet apart, and where ground-cover is scanty…, near such as does occur” in habitats or situations which are expected to yield specimens of Ceuthophilus: almost any type of forest, rock piles, stone fences, vicinity of the openings of mammal burrows, caves, certain grasslands, etc….

Three North American species of Latalus and four of Quontus were listed by Oman (1999). Two of these are conspecific with a third and three new species are described below. Two of the previously described species have not been found in Canada and are not discussed here. They are Deltocephalus latidens Sanders and DeLong (1919, p. 234) and Latalus uncinatus Beamer and Tuthill (1934, p. 6). They are distinguished by genitalic characters described in the original descriptions. Quontus Oman (1949) is treated here as a synonym of Latalus DeLong and Sleesman (1929), as the distinctions given by Oman (1949) intergrade and do not always hold good. Canadian species of Latalus apparently inhabit grasslands. The best specific characters are in the internal male genitalia, though the female seventh sternite shows valid characters in some species.

The toxicities of a large number of spray chemicals to arthropod pests are well known. In most instances, observations on the effects of such materials on natural enemies have beeen incidental to other studies, and little has been published on experiments designed to determine the direct toxicities of the chemicals to beneficial species. The effects of spray chemicals on the predators and parasites of the major pests of apple trees in Nova Scotia have been investigated as part of a broader project on the factors that influence population densities of orchard arthropods, as outlined by Pickett et al. (31).

The larval stages of Hilarella hilarella (Zett.) have been previously reported as living on the stores in the nests of fossorial Hymenoptera. This fly is here reported as parasitizing an insect host without the intervention of any hymenopterous insect.

On June 8, 1910, in the woods near Brookline, Massachusetts, W. F. Fiske, then in charge of the Gipsy Moth Parasite Laboratory, collected an adult of the rare beetle Chromatia amoena Say (determination by the late Dr. E. A. Schwarz). Having no killing bottle, he placed the specimen in a match box. On the following day he found that the larva of a Dipternus parasite had issued and pupated in the box. The adult failed to emerge and the puparium was unfortunately discarded. In an attempt to determine something of the life history of the parasite, I dissected the dead host and found in it the first and second stage mouth hooks and the second stage posterior spiracles which were of such unusual structure that they seemed worth while describing. A short paper on the parasite was therefore published in 1913l in the journal published by Professor F. Silvestri, in whose laboratory I was then working.