Metamorphosis in the pupae of the Trypoxylus dichotomus was continuously observed at 9.4T until their emergence. A large liquid-like mass occupied most of the volume in the trunk, while the surrounding tissue already existed at the beginning of the observation period. As the mass shrunk, tissues such as flight muscle formed, whereas the reservoir became prolonged to form the intestinal tract. This implies that the liquid-like mass worked as the raw material for creating adult tissues.