INSECTS 



cavity in the earth, perhaps two by three feet in diameter 

 and a foot beneath the surface, walled with a thick cement 

 lining; but from this chamber there may extend tunnels 

 upward to the surface, or horizontally to other smaller 

 chambers located at a distance from the central one. 

 The termites that live in these nests subsist principally 

 upon home-grown food, and it is in the great vaulted 

 central chamber that they raise the staple article of their 

 diet. The cavity is filled almost entirely with a porous, 

 spongy mass of living fungus. The fungi as we ordinarily 

 see them are the toadstools and mushrooms, but these 

 fungus forms are merely the fruiting bodies sent up from 

 a part of the plant concealed beneath the ground or in 

 the dead wood; and this hidden part has the form of a 

 network, of fine, branching threads, called a mycelium. 

 The mycelium lives on decaying wood, and it is the 

 mycelial part of the fungus that the termites cultivate. 

 They feed on small spore-bearing stalks that sprout from 

 the threads of the mycelium. The substratum of the 

 termite fungus beds is generally made ot pellets of partly 

 digested wood pulp. 



The nests that termites erect above the ground include 

 the most remarkable architectural structures produced 

 by insects. They are found in South America, Australia, 

 and particularly in Africa. In size they vary from mere 

 turrets a few inches high to great edifices six, twelve, 

 or even twenty feet in altitude. Some are simple mounds 

 (Fig. 86 A), or mere hillocks; others have the form of 

 towers, obelisks, and pyramids (B); still others look 

 like fantastic cathedrals with buttressed walls and taper- 

 ing spires (Fig. 87); while lastly, the strangest of all re- 

 semble huge toadstools with thick cylindrical stalks and 

 broad-brimmed caps (Fig. 86 C). Many of the termites 

 that build mound nests are also fungus-growing species, 

 and one chamber or several chambers in the nest are 

 given over to the fungus culture. 



Termite nests built in trees are usually outlying retreats 



[148] 



