none Larvae of Hedya nubiferana Haw. and Pandemis heparana Den. & Schiff. were collected from rolled apple leaves and reared until pupation under laboratory conditions. The pupae were then kept in outdoor isolators until the emergence of adults and their progenies were used in the 2nd larval stage in the parasitization experiments. The Macrocentrus pallipes Nees adults were obtained from naturally parasitized Hedya larvae. Both parasitized and normal Hedya larvae underwent diapause as well as the parasitized Pandemis larvae while the unparasitized larvae of the latter continued their development to give a second generation.