44 ANTS AVOID THE OPEN AIR. 



expose themselves to the open air, without the great- 

 est necessity; but either travel under ground, or 

 within such trees and substances as they destroy. 

 If that necessity occurs, they makes pipes, of the 

 same composition as their nests, varying the ma- 

 terials according to their kind ; one species using red 

 clay, another black clay, and a third a woody sub- 

 stance cemented with gums, as a security from the 

 attacks of their enemies, particularly the common 

 ant, which, being defended by a strong, homy shell, 

 is more than a match for them, and when they can 

 get at them, rapaciously seize them, and drag them 

 to their nests, for food for their young brood. If 

 any accident breaks these pipes, they repair the 

 breach with all speed. Instinct guides them to per- 

 form their office in the creation, by mostly confining 

 their attacks to trees that are beginning to decay, 

 or such timber as has been severed from its root 

 for use, and would decay in time. Vigorous, 

 healthy trees do not require to be destroyed, and, 

 accordingly, these consumers have no taste for 

 them. i 



On opening one of their hills, a general alarm is 

 excited. Some of the fighting insects immediately 

 run to the place, and appear to survey the mischief, 

 though they can only do so by feeling, as it may 

 be remembered that they are blind: their quick 



