96 THE STORY-BOOK OF SCIENCE 



are endowed with an incomparable appetite. As I 

 have said, to eat is their sole business. They eat 

 night and day, often without stopping,' without taking 

 breath. To lose a mouthful, what imprudence! 

 The future butterfly would perhaps have one scale 

 less to its wings. So they eat gluttonously, take on 

 a stomach, become big, fat, plump. It is the duty of 

 larva?. 



"Some attack plants; they browse on the leaves, 

 chew the flowers, bite the flesh of fruit. Others have 

 a stomach strong enough to digest wood; they hol- 

 low out galleries in the tree-trunks, file off, grate, 

 pulverize the hardest oak, as well as the tender \\\\- 

 low. Others, again, prefer decomposed animal mat- 

 ter; they haunt infected corpses, fill their stomachs 

 with rottenness. Still others seek excrement and 

 feast on filth. They are all scavengers on whom 

 has developed the high mission of cleansing the earth 

 of its pollution. You would sicken at the mere 

 thought of these worms that swarm in pus ; yet one 

 of the most important services, a providential serv- 

 ice, is rendered by these disgusting eaters which 

 clear away infection and give back its constituent 

 elements to life. As if to make amends for its filthy 

 needs, one of these larvae will later be a magnificent 

 fly, rivaling polished bronze in its brilliancy; an- 

 other, a beetle perfumed with musk, its rich coat 

 vying with gold and precious stones in splendor. 



"But these larvae devoted to the work of general 

 sanitation cannot make us forget other eaters, of 

 whom we are victims. The grubs of the June bug 

 alone sometimes multiply so rapidly in the ground 



