The nymphal period of Palomena angulosa MOTSXHULSKY was the shortest under 12L-12D photoperiod and shorter under 14L-10D than under 15L-9D. The relationship between the nymphal period from the 2nd instar to the adult and the length of stationary photophase was similar to that under changing (decreasing) conditions of photoperiod. The profiele of food consumption after moulting in the 5th instar differed markedly between the 12L-12D and 15L-9D groups. The activities of five kinds of enzymes in the digestive sysmtem were higher in the 15L-9D group than in the 12L-12D group, when assayed at the middle of the 5th instar. Taking the protein content in the midgut as well as the food consumption into consideration, it was suggested that photoperiod influenced the feeding activity of P. angulosa nymphs.