186 INSECT ARCHITECTURE. 



awa}^ tlie 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 

 undei'neath ; 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 state- 

 ment, 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 bod}^ it must have 



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



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 the stone, it crawls up the side of the pit with 

 great care, and deposits its burthen on the outside of the 



