Results of laboratory trials showed a negative effect of the age of adults of Trichogramma demoraesi on the parasitism of eggs of Anagasta kuehniella and on the lenght of the immature stage of the parasitoid. These parameters were constant for insects 2 to 6-day-old and decreased significantly after the sixth day. The highest parasitism rates and immature stage lenght, for insects fed or not with a 50% honey solution, were obtained with 4 to 6-day-old adults and the parasitism did not occur with 10-day-old adults. Males of A. kuehniella kept together with females in the cages increased the fecundity of the moths by 938.75% when they were kept without food and by 393-95% when they were fed with honey diet. The females longevity did not vary in function of the diet and it was slightly less in the females than in the males. When eggs of A. kuehniella containning the parasitoid in the pupal stage were stored at 5°C, there was no effect on the emergence of the parasitoid until 7 days of storing, with a small though continuous reduction on the emergence after this period of storing.