II FOOD OF INSECTS 69 



furious exertions to find release they send down the 

 sand in torrents, which fills up the pit, rendering its 

 sides far less steep and therefore easier to surmount, for 

 a powerful insect is better able to withstand such an 

 avalanche than a tiny ant Then ensues a battle royal, 

 the one opponent fast bringing down the sand which 

 the other as determinedly ejects, being bent on keep- 

 ing itself free and on restoring its house to its pristine 

 neatness. Sometimes a load flung by the Ant-Lion 

 strikes the retreating creature unawares, and it loses 

 its balance never to regain it, giving the larva just the 

 opportunity that it needed to grasp it in its terrible 

 sickle-shaped mandibles. Sometimes the captive 

 becomes exhausted before the Ant-Lion and allows 

 itself to be caught ; and sometimes, though rarely, the 

 onslaught ends in victory on the former's part, and 

 it succeeds in making good its escape. In any case 

 the pit has suffered such damage that its owner does 

 not spend time on rearranging and repairing it, but 

 abandons it, and starts on a fresh series of excavating 

 operations. 



In this manner, burrowing in the earth and catching 

 living prey, the larva lives until it is full-grown and 

 fed. The early immature period lasts for about two 

 years. It then retires under the sand, and spins a 

 cocoon of silk mingled with sand, and after the lapse 

 of a few weeks is transformed into the winged and 

 perfect state. The adults are not in the least like the 

 larvae. It would be hard to conceive a more complete 

 contrast, and were the two forms placed side by side 

 no one unacquainted with the circumstance would 

 believe them to be but two stages of the same insect. 



