none. Hyposoter didymator Thunb. was found to parasitize 0-6 day old Spodoptera litura (F.) larvae in the laboratory at 24.5 +- 1 degree C and 65 percent RH. Effect of host age on developmental period of immature stages, sex ratio of adults, size of the progeny and degree of successful parasitism (survivorship) of the parasitoid were investigated. There was a significant negative correlation between the host age and the parasitoid developmental period, while the size of the progeny was observed to increase with the age of the host. Maximum parasitism was observed in 5-day-old host larvae.