72 
ENEMIES OF THE CATERPILLAR. 
little teeth at the end, like a saw; and a hollow 
channel runs down it for the eggs to jiass through. 
When it is shut up in its sheath, it looks only 
like a bristle coming out at the fly’s tail. 
Ichneumon fly. The borer magnified. 
i 
When the ichneumon fly is about to lay her eggs, 
she alights on the plant, where the caterpillar is 
likely to be found, and runs hither and thither 
examining every leaf. Presently, she espies her 
victim, and immediately perches herself on its 
back. Then she plunges her sharp weapon into 
its body, between one of its rings, and lays an 
egg in the hole. In a few seconds, she repeats 
the operation in a different place; always taking 
care to lay her eggs so deejD, that the caterpillar 
cannot throw them off when it changes its skin. 
She is so intent on her work, that you might 
