In the Lepidoptera the different cuticles of the caterpillar, of the pupa and of the adult are produced by the same epidermis, without regard to increase and polyploidisation of epidermis cells.By histological and morphological investigations it could be shown, which parts of the skin on an abdominal segment ofGalleria mellonella correspond to eachother in these three stages of development. A skin graft, heterotoply transplanted from one caterpillar to another as well as the experimental surroundings of that graft, do not develop corresponding to their normal prospective fate during metamorphosis. In grafting experiments a kind of regulating development takes place. The skin of the graft and its surroundings always develop by locally producing a succession of skin types which is normally to be found along the main axis of an adult segment: Morphological polarity is locally altered in grafting experiments. In the skin regions where morphological polarity is altered experimentally, the scales are no longer orientated parallel to the main axis of the body nor do they show an orientation parallel to the experimentally evoked "new segment axes". The scales show intermediate orientations. From the manner of morphological differentiation and scale orientation in the graft experiments a relationship may be concluded between the morphogenetic systems of the segmental epidermis inGalleria and of the early germ of the sea urchin.