v] TRANSFORMATIONS 49 



the action of internally formed destructive substances, 



I and one function of the phagocytes is to act as 

 scavengers by devouring what has become effete and 

 useless. 



CHAPTER VI 



LARVAE AND THEIR ADAPTATIONS 



AMONG the insects that undergo a complete trans- 

 formation, there is, as we have seen in the preceding 

 chapter, an amount of inward change, of dissolution 

 and rebuilding of tissues, that varies in its com- 

 pleteness in members of different orders. It is now 

 advisable to consider the various outward forms 

 assumed by the larvae of these insects, or rather by 

 a few examples chosen from a vast array of well-nigh 

 'infinite variety.' 



In comparing the transformations of endopterygote 

 insects of different orders, it is worthy of notice that 

 in some cases all the members of an order have 

 larvae remarkably constant in their main structural 

 features, while in others there is great variety of 

 larval form within the order. For example, the 

 caterpillars of all Lepidoptera are fundamentally 



c. i. 4 



