Winthemia occidentis Rhn. was introduced into Newfoundland to strengthen the parasite complex of the eastern hemlock looper. This tachinid has two emergence periods, one in the fall, the other in the following spring. A method was developed for rearing overwintering tachinid larvae to the adult stage. The best rearing results were obtained when the larvae were stored outdoors in jars of peat moss for the fall and winter period and removed to controlled temperature and humidity conditions in the spring, to complete development.