Abstract
Siphona irritans (L.), commonly known as the horn fly, is a serious pest of cattle. In southern Alberta, ten thousand flies have been counted on a single host animal. Properly conducted control studies require the establishment of a permanent laboratory colony. Previous attempts to establish such a colony had not been successful (McLintock and Depner, 1957) as more information about the biology of the fly was needed. The results presented in this paper will help provide this information.