Flavonoids in the eggs, larvae, pupae and adult butterflies of Pseudozizeeria maha were identified and quantified. Isovitexin (apigenin 6-C-glucoside) was the dominant flavonoid detected in pupae and imagines, whereas saponarin (isovitexin 7-O-glucoside) was the dominant flavonoid in larvae. Saponarin, biotransformed from isovitexin by the larvae, was found to be reconverted into isovitexin at the pupal stages. The total amounts of accumulated flavonoids differed between sexes, particularly in adults where the bodies of females had a much higher flavonoid concentration than that of the males. These flavonoids were also detected in the eggs. These results indicate the possibility that flavonoids are utilized in not only wing coloration but also as a chemical defense compound against natural threats.