INSECTS. 



193 



further because the sand will tumble down as fast as the larva could throw 

 it out. The ant-lion now works its body under the sand at the bottom of 

 the hole, having only its jaws exposed. If, now, an ant wanders over the 

 brink of the pit, the sand gives way under its feet, and it tumbles down 





Fig. 179. — Adult ant-lion (Myrmeleo), with the pit, showing the protruding jaws of the larva. 



toward the centre and the expectant jaws. The ant-lion now throws up 

 more sand so as to aid in bringing down the prey, and at last the jaws 

 close upon the victim. After a long life of this character, the ant-lion 

 spins a cocoon, changes to a pupa, and at last emerges a perfect insect, 



Fig. ISO. — Different forms of cases of carhlis-worms. 



much like a dragon-fly in its general appearance, of which there is but little 

 of general interest to record. 



The larvae of the caddis-flies or case-flies parallel, among insects, the 

 hermit-crabs. With only a single known exception they are all aquatic. 



