ENEMIES OF PLANTS. 



321 



arrangement is to prevent their being eaten by 

 larvae, not only of other insects, but of those of 

 their own family, for they are veritable cannibals. 

 The larvae (Fig. 113,^) are as ugly as the adult is 

 beautiful. They are active, spindle-shaped little 

 fellows with crescent- 

 shaped mandible s, 

 which never seem to 

 tire of piercing to 

 death all insects they 

 can capture ; but they 

 are particularly de- 

 structive to plant-lice 

 (aphides), and for this 

 reason are often called 

 aphis lions. They 

 hold their prey be- 

 tween the tips of their FIG - "4. ICHNEUMON-FLY DK- 



pnsiTiMfi AM vnn WITHITJ rnrrmivr. 



mandibles, and suck 

 the juices through the 

 long tubes formed by a groove along the under 

 side of each mandible and the slender maxilla 

 which fits into it. When this larva reaches its 

 growth it rolls itself into a ball and spins a 

 cocoon of snowy white, from which it comes 

 forth through a circular lid (Fig. 113, y) a 

 wondrously changed creature the dainty lace- 

 winged fly. 



Another group of our insect friends is the 

 parasitic Hymenoptera, such as the ichneumon* 



POSITING AN EGG WITHIN COCOON. 

 (Slightly magnified.) 



