1. Grafts including intersegmental membrane have confirmed the existence of a segmentally repeating gradient of incompatibility in the integument of Rhodnius. 2. When host and graft influence one another the pattern can be predicted from the interaction of the gradients. When a graft is uninfluenced by the host the anterior part of the graft is dominant in restoring pattern continuity. 3. The intersegmental membranes are neutral with respect to the gradient behaviour. 4. The gradient is not restricted to the area forming the ripple pattern but includes other patterns in the abdomen.