The predatory gall midge, Aphidoletes aphidimyza (Rondani 1847), is a biological control agent used worldwide to control aphids. Mass-production methods are well established in Canada, the Netherlands, England, Germany, Finland, and the former U.S.S.R. (cf. van Leiburg and Ramakers 1984). In early March 1991, after 6 years of massproduction of A. aphidimyza on a rapidly increasing scale, two minute adult hymenopterous parasitoids were observed eclosing from a sample of pupae at a commercial insectary in British Columbia. It is likely that the founding parasitoid individual(s) entered the greenhouse before winter, as parasitoids appeared too early in the year to have entered from outdoors at that time.