The male accessory reproductive glands (ARGs) of the tobacco caterpillar, Spodoptera litura begin development on 6th day of the pupal stage. The synthetic activity of the gland begins from the eighth day pupal stage as shown by 3H-leucine incorporation studies. There is a significant increase (2.4-fold) in the specific activity of 3H-leucine incorporation into TCA precipitable proteins in 10 hr old males when compared to newly emerged males (0 hr), and this synthesis is partially blocked (60%) by cycloheximide (5μg/insect) treatment.