XIV. An enquiry into the cause and extent of a special colour-relation between certain exposed lepidopterous pupœ and the surfaces immediately sur­round them

Abstract

The present investigation grew out of the enquiry into the colour-relation between Lepidopterous larvae and their food-plants. In the search for the larval sense-organ which is affected by the light reflected from surrounding surfaces, great difficulty was experienced from the fact that the influences work slowly through the whole of larval life. Thus the ocelli must be eliminated by blinding five times in the life of each caterpillar, and there is always the chance of the skin being thrown off a little earlier than usual, in which case the success of the whole experiment might be endangered, for the coverings of the eyes are changed with the rest of the skin. It seemed probable that in the pupal colour-relation the influence must act during a short and rigidly limited time, in which experiments could be conducted with much hope of a successful isolation of the effective sense-organs.