We investigated the developmental mechanism underlying the control of diapause pupal coloration in the cabbage white butterfly Pieris rapae crucivora. Over 90% of larvae reared under short-day conditions developed into diapause pupae of brown or light-brown types irrespective of yellow or black background colors. To investigate whether a cerebral factor is involved in the developmental coloration of diapause pupae, 2% NaCl extracts prepared from pupal brain-subesophageal ganglion complexes were injected into the ligatured abdomens of mature short-day larvae. A large portion of these larvae developed into pupae of green types. These results suggest that a cerebral factor inducing green coloration exists in pupal brain-subesophageal ganglion complexes, and mature short-day larvae, which do not develop into diapause pupae of green types, maintain the cerebral factor.