The method to obstruct the embryonic development of eggs of the Ephestia moth which were parasitized by Trichogramma chilonis and T. oslriniae for mass culture of them was investigated. The eggs of Ephestia kuehniella and E. caulella were used for the experiment The hatching ratio of the moth eggs was 0% after exposure of the ultraviolet light (NEC, GL-15 lamp) for 8 minutes (250, 632μW/cm^2) for E. kuehniella and 10 minutes (320, 400μW/cm^2) for E. cautella.