INTERRELATIONS OF INSECTS 



319 



FIG. 275. 



substitution royalties may contain workers or even soldiers 

 capable of laying eggs. 



Architecture. While many termites simply burrow in dead 

 wood, other species construct more elaborate nests. A Jamai- 

 can species builds huge nests in the forks of trees, with covered 

 passageways leading to the ground. 



In parts of Africa and Australia, where they are free from 

 disturbance, termites erect huge mounds, frequently six to ten 

 and sometimes eighteen or twenty feet high, with galleries 

 extending as far below the 

 surface of the ground as 

 they do above it. These im- 

 mense structures (Fig. 275) 

 consist chiefly of earth, ce- 

 mented by means of some 

 secretion into a stony clay, 

 with which also much excre- 

 mentitious matter is mixed; 

 they are pyramidal, colum- 

 nar, pinnacled or of various 

 other forms, according to 

 the species, and are perfor- 

 ated by thousands of pass- 

 ages and chambers, while 

 there are underground gal- 

 leries extending away from 

 the mound to a distance 

 of often several hundred 

 feet. 



An extraordinary type of mound is constructed by the 

 " compass," or *' meridian," termites of North Australia, for 

 their wedge-shaped mounds (Fig. 276), commonly eight or 

 ten feet high, though sometimes as high as twenty feet, are 

 directed north and south with surprising accuracy. By means 

 of this orientation the exposure to the heat of the sun is re- 

 duced to the minimum, as occurs also in the case of many Aus- 



Termite mound, Kimberley type, Australia. 

 After SAVILLE-KENT. 



