74 GRAMMAR OF ENTOMOLOGY. 



as to remove the sand within the circle with the 

 inner leg ; but it knows that it is the sand within 

 the circle that is to be excavated, and it therefore 

 constantly uses the leg next the centre. 



235. After the first series of circles is com- 

 pleted, a second, of less diameter, and deeper, is 

 commenced within it ; and so on with others, 

 until the hole assumes the shape of the impression 

 of an inverted cone, when the work is finished. 



236. As the constant use of one leg during 

 the whole of this operation would necessarily 

 exhaust the animal so much that it would be 

 compelled to waste much time in recovering its 

 strength, it adopts a plan which prevents this : 

 the first circle is excavated with one foot ; it 

 then turns completely round, so that the second 

 is excavated with the opposite foot ; and this 

 alternation proceeds regularly through the whole 

 work. 



237. Small stones are jerked out by its head 

 in the same manner as the sand, but larger ones 

 occasion more trouble : when it meets with one 

 too heavy to jerk out, the ant-lion poises it on 

 its back, keeps it in a steady position by the 

 motion of the segments of its body, and care- 

 fully walking up the ascent with its burden, 

 deposits it on the outside of the margin. 



238. Sometimes the stone, from its roundness, 

 will slip from the back of the labourer, and roll 

 down the side of the hole a dozen times ; as often 



