INTERRELATIONS OF INSECTS 



263 



chambers, while there are underground galleries 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. 280), 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 reduced to the minimum, as occurs 

 also in the case of many Australian plants, 

 the leaves of which present their edges in- 

 stead of their faces to the sun. 



More than one species of termite may 

 inhabit a single nest; in one South African 

 nest Haviland found five species of ter- 

 mites and three of ants. The widely dis- 

 tributed genus Eutermes is essentially a 

 group of inquiline, or guest, species. Ter- 

 mite mounds afford shelter to scorpions, 

 snakes, lizards, rats, and even birds, some 

 of which nest in them. The Australian 

 bushmen hollow out the mounds to make 

 temporary ovens, and even eat the clay of 

 which they are composed, while hill- 

 tribes of India are accustomed to eat 

 the termites themselves, the flavor of 

 which is said to be delicious. 



Ravages. In tropical regions the 

 amount of destruction done by termites 

 is enormous, and these formidable pests 

 are a constant source of consternation 

 and dread. They emit a secretion that 



corrodes metals and even glass, while anything made of wood is simply at 

 their mercy. Always avoiding the light, they hollow out floors, rafters 

 or furniture, leaving only a thin outer shell, and as a result of their in- 

 sidious work a chair or a table may unexpectedly crumble at a touch. 

 Jamestown, the capital of St. Helena, was largely destroyed by termites 

 (1870) and had to be rebuilt on that account. 



In the United States and Europe few species of termites occur, and 

 they do little injury as compared with the tropical species; though our 



FIG. 280. Mound of the "com- 

 pass" termite of North Australia. 

 After SAVILLE-KENT. 



