INSTINCT AND INTELLIGENCE. 



, commonly called the ant-lion, represented in its 

 natural size in fig. 1, the larva of which is also represented in its 

 natural size in fig. 2. This larva feeds upon ants and other insects, 

 of which it sucks the juice ; but as its powers of locomotion are 

 greatly inferior to those of its prey, it would perish for want of 

 nourishment, if Nature had not endowed it with instinctive 

 faculties by which it is enabled to capture by stratagem the 

 animals upon which it feeds. 



18. After having carefully surveyed the ground upon which it 

 is about to operate, it commences by tracing a circle corresponding 

 in magnitude with its intended snare. Then placing itself within 

 this circle, and using one of its feet as a spade or shovel, it sets 

 about making an excavation with a tunnel-shaped mouth. It 

 throws upon its head the grains of sand which are digged up with 

 its feet, and by a jerk of its body it flings them to a distance of 

 some inches outside the circle which it has traced, throwing them 

 backwards by a sudden upward movement of the head. Pro- 

 ceeding in this way it moves backwards, following a spiral course, 

 continually approaching nearer to the centre. At length so much 

 of the sand is thrown out that a conical pit is formed, in the bottom 

 of which it conceals itself, its mandibles being the only parts which 

 it allows to appear above the surface. If in the course of its work 

 it happens to encounter a stone, the presence of which would 

 spoil the form of the pitfall, it first pays no attention to it, and 

 goes on with its labour. After having finished the excavation, 

 however, it returns to the stone, and uses every effort to detach it, 

 to place it on its back and throw it out of the pit. If it do not 

 succeed it abandons the work, and departs in search of another 

 locality, where it recommences with admirable patience a similar 

 excavation. 



These pitfalls, fig. 3, when completed, are generally about three 



inches in diameter and 

 two in depth ; and when 

 the slope of the sides has 

 been deranged, which 

 almost always happens 

 when an insect falls into 

 it, the ant-lion imme- 

 diately sets about repair- 

 ing the damage. 



When an insect hap- 



Fig. 3. Pitfall of an Ant-Lion. P ens to fal1 into tne P^ 



the ant-lion instantly 



seizes it and puts it to death, and the fluids having been all sucked 

 out, its dry carcass is treated exactly like the grains of sand, and 

 120 



