The Ant- Lion. 231 



each step is thrown on the head, owing to the hump-like 

 form of the back : this is immediately jerked away, the body 

 at the same time advancing another step in its backward and 

 spiral motion. Where it rests, a little hillock of sand is 

 raised by the body of the ant-lion underneath ; while its 

 jaws emerge and spread flat on the surface. It now probably 

 commences its pitfall, the mode of excavating which we have 

 given in detail. From the spiral course described by the 

 ant-lion in its backward progress appears to have arisen the 

 idea of its tracing out a circle as the outline of its pitfall 

 as would an architect or engineer ; but whence sprang the 

 often-repeated statement, that the ant-lion loads its head 

 with sand by means of one of its legs, that nearest the 

 centre of the circle, we cannot conjecture. Nor do we know 

 how, as it works entirely buried with the exception of the 

 head, the ant-lion can act when it meets with a stone or other 

 obstacle, as M. Bonnet states he has repeatedly witnessed. 

 He observes that if the stone be small, it can manage to jerk 

 it out in the same manner as the sand ; but when it is two 

 or three times larger and heavier than its own body, it must 



Ant-Lion's Pitfalls, in an experlmenting-box. 



have recourse to other means of removal. The larger stones 

 it usually leaves till the last ; and when it has removed all 

 the sand which it intends, it then proceeds to try what it can 

 do with the less manageable obstacles. For this purpose it 

 crawls backwards to the place where a stone may be, and 

 thrusting its tail under it, is at great pains to get it properly 

 balanced on its back, by an alternate motion of the rings 

 composing its body. When it has succeeded in adjusting 



