HISTORY OF INSECTS. 81 



gains admittance, to pass off into subterraneous 



263. These passages, some of which are a foot 

 in diameter, and perfectly cylindrical, are lined 

 with clay. They originally served as quarries, 

 whence the materials of the building were derived, 

 and afterwards as the galleries by which the 

 inmates travel under ground, to carry on their 

 depredations at a distance from their home. 



264. These galleries run slantingly downwards 

 to the depth of two or three feet, then branching 

 out in every direction, rise nearly to the surface, 

 and are carried under ground to an almost incre- 

 dible distance. 



265. There are numerous minor galleries inter- 

 secting every part of the nest, and winding round 

 it in different directions to the very top, conti- 

 nually cross each other ; many of these open into 

 the dome in various places. All these minor 

 galleries eventually merge in the large ones be- 

 neath the nest. 



266. The white ants cannot ascend a perpendi- 

 cular surface; yet these galleries in parts are 

 quite perpendicular. The difficulty is overcome 

 by the formation of a spiral pathway of easy 

 ascent, and half an inch in width, which is con- 

 structed of clay, against the wall of the gallery, in 

 the way of a geometrical staircase. 



267. In order to convey the eggs from the 

 royal chamber to the upper nurseries, several 



