Abstract: At present it is well known that the mitochondria are formed by a close intereaction of two distinct genctic systems: the nucleo-cytoplasmic system and the cell are assembled.The present investigation provides some evidences indicating that during the process of mitochondria biogenesis in armyworm species the outer mitochondreal membrane is formed first,followed by the inner mitochondrial membrane and crestae system; but in locust species the mitochodria biogenesis process begins with the formation of inner mitochondrial membrane vesicles followed by the outer mitochondrial membrane.The experimental results obtained from these two insects are summarized as follows:I. Electronmicroscopic examinations (Plates I:1-4, II:5-6) indicated that their mitochondria of armyworm are formed from non-membraneous precusors (macromalecute particles).