Abstract
Microctonus aethiops(Nees) auctt. (Fig. 1) andPerilitus rutilus(Nees) are parasites of adultSitonaweevils in Europe. They were released in Canada as control agents of the sweetclover weevil,Sitona cylindricollisFahr. (Fig. 2). The immature stages and biology of the species were studied as a prerequisite to attempts at biological control. A similar investigation of the braconidPygostolus falcatus(Nees) was completed (Loan and Holdaway, 1961). Jackson (1928) described some aspects of the biology ofP. rutilus, and additional data are given in the present paper.