Abstract
In view of the economic importance of blackflies as bloodsucking insects affecting animals and man, and the growing recognition of their actual and potential role as vectors of disease, it has been considered of interest to record the following notes concerning certain of their natural enemies, some of which may prove to be of value in developing biological control measures. These observations were made at various times over a period of several years, in connection with a study of blackflies carried out chiefly in the Ottawa district, the results of which have been published elsewhere.