Armyworm, Leucania separata Walker, is characterized as a species of migratory. But there are two-life forms, migratory and resident, within the species population often accompanied by a corresponding Physical diffevence. Diffevent contents of the energy sources materials of these two life form organisms were examined. Fat bodies taken out from the abdomen were sectioned for microscopically histological observation. The results indicate that lipids are the main energy sources material.