THE CATERPILLAR AND THE BUTTERFLY 



By R. E. SNODGRASS 



Research Associate 

 Smithsonian Institution 



INTRODUCTION 



The caterpillar and the butterfly are here given the title role because 

 they are a familiar example of those insects in which the young differ 

 so much from their parents that they must go through a reconstruction 

 called a metamorphosis in order to attain their own adult form. So 

 well known, in fact, is the apparent transformation of the wormlike 

 caterpillar into the splendid winged butterfly, and so marvelous does 

 it seem, that it has been taken as a symbol of human resurrection. In 

 ancient Greek the human mind or soul was called psyche, and the same 

 name was given to the butterfly, presumably the emancipated soul of 

 the caterpillar. Though the process of resurrection is obscure, and 

 the fact has perhaps not been fully demonstrated, we now know 

 almost the whole story of how the caterpillar appears to become a 

 butterfly. Furthermore, in recent years students of insect meta- 

 morphosis have given much attention to the role of hormones in con- 

 trolling the life of the young insect and the development of the 

 adult. In short, almost the whole of modern studies on insect meta- 

 morphosis has been devoted to understanding the change of the larval 

 insect to the adult, or imago. 



On the other hand, little attention has been given to the question 

 as to how or why did the young moth or butterfly ever become such 

 a thing as a caterpillar, a creature so different in every way from its 

 parents. It would indeed be a wise butterfly that knows its own child, 

 since probably it has no memory of its own youthful life as a cater- 

 pillar. Equally certain is it that the caterpillar has no idea that it 

 will ever be a butterfly. 



With most animals, including many insects, the young resemble 

 their parents except in matters of immaturity. Consider the young 

 grasshopper or the young cockroach — they differ from their parents 

 principally in the incomplete development of their wings and the 

 external genital organs. They have no need to fly since they live in 



SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 143, NO. 6 







