Abstract: The active prothoracic glands from non-diapause Helicoverpa armigera have larger space among cells and are dyed easily, their cells are characterized by large and irregular nuclei, and abundance of rough endoplasmic reticulum, smooth endoplasmic reticulum and a moderate amount of mitochondria; the inactive glands from diapause H. amigera have small space among cells and are not dyed easily, their cells have small and regular neulei, few rough endoplasmic reticulum and smooth endoplasmic reticulum, less mitochondria.

Key words: Helicoverpa armigera, diapause, prothoracic glands, morphology