larva and pupa of PapiUo Nireus. 52 1 



The question however naturally arises, are the changes 

 described pi-oduced by the desire or will of the caterpillar, 

 like those which take place in the lizard of Griqualand, or 

 in the chameleon, or is it merely an instance of nature's 

 conservative power, brought about without any effort on 

 the part of the creature itself ?_a sun picture or i^hoto- 

 g-raph. 1 on are aware of the exceedingly transijarent nature 

 ol a pupa during the first day of its existence in that form — 

 may it not m that state have the property of absorbino-'or 

 reflecting the surrounding colours, and thus become^he 

 means of its own concealment and jDreservation ? That 

 the caterpillar is aware of the change that will take place 

 m Its altered colour, I am fully convinced. I have no 

 doubt whatever, that when the insect placed itself upon 

 the dark-brown surface of the case, it was aware tliat the 

 result would not be a bright-green pupa exposed upon a 

 dark-brown surface to the vision of its enemies. 



Moreover, I have several times observed that the larva 

 of the Sphinx moth never differs in colour from that of 

 the leaves upon which it feeds, excepting in its last 

 change. ^ To be, however, more explicit, the caterpillar of 

 the Sphinx moth changes its skin many times while feed- 

 ing, keeping true to the colour of the leaves of its food 

 ]:)lant, until it has attained its full growth, and requires no 

 further food. It then, previous to casting its shin for the 

 last time as a caterpillar, retires to a sheltered spot, mostly 

 the hrow7i stem of its food plant, and throwing off its 

 green coat, for which it has no further use, it assumes 

 a dark-brown, earthen-coloured one. In this form it is 

 destined to traverse the earth in search of its future habita- 

 tion, in which as a pupa buried beneath dried leaves, or 

 slightly beneath the soil, it has to pass the long winter 

 months. If the caterpillar in its bright-green coat, ex- 

 posed to its enemies, had to seek out its future hiding- 

 l^lace, how slight would be its chances of escape ; its 

 earthen colour is, therefore, of the greatest service to it, 

 as was that of the green while feeding amongst the green 

 leaves, — hence the cause of the wonderful changes which 

 take place in the colour and form of these insects. 



