CH. XIII.] THE ANT-LION. 221 



traces in the sand a circular furrow which is to de- 

 termine the extent of its future abode. The outline 

 of the hollow which it intends to excavate being 1 

 drawn, it proceeds with its task. Placing itself on 

 the inside of the circular furrow previously traced, 

 it thrusts the hind part of its body like a plough- 

 share, under the sand ; and using one of its fore- 

 legs as a shovel, it deposites a load of sand upon 

 its head, which is flat and square : it then gives its 

 head a jerk, sufficiently strong to toss this load to a 

 distance of several inches beyond the outward cir- 

 cle. All this is executed with a wonderful degree 

 of celerity and address. Always going backwards, 

 the same process is repeated, until it reaches that 

 part of the circle where it commenced its opera- 

 tions. Another furrow is then excavated inside of 

 the first circle ; this is succeeded by others, until at 

 last the insect arrives at the centre of its intended 

 hollow. One peculiarity deserves to be pointed 

 out ; the insect neither uses its outward leg nor dis- 

 turbs the sand lying on the outside of the circle ; 

 using the inner leg only, it loads its head with sand 

 taken from the inside of the circle. It seems to be 

 well aware that the sand within the circle is all that 

 requires to be removed, and also that this can be 

 effected only by using the inside leg. If both the 

 legs were used at the same time, the excavation 

 would assume the shape of a cylinder, and not that 

 ,of a cone ; which is the only form that can suit the 

 purpose of the insect. It must, however, be obvious, 

 that if, throughout the whole of this laborious pro- 

 cess, one leg continued to be exclusively used, the 

 limb would get tired. To obviate this inconveni- 

 ence, nature has taught the little pioneer to adopt an 

 apt expedient : one furrow having been completely 

 excavated, another is traced in an opposite direction ; 

 this brings into play the leg which had been previ- 

 ously at rest. It frequently happens that small 

 Btones impede the progress of its labours; these. 

 T2 



