170 ANTS, BEES AND WASPS 



aloft in its jaws a tiny piece of leaf like a little umbrella, and from 

 this they have gained their popular name of Umbrella Ants. The 

 pieces of leaf are used to form a kind of thatch over the mounds 

 which rise above the entrance to the subterranean nests, the thick 

 layer of leaves being finally covered with a layer of earth which 

 the workers bring up from some depth below the surface of the 

 ground. 



Besides stripping the young trees of their foliage, armies of 

 Sauba Ants will sometimes raid houses at night and carry off the 

 stores of farinha or mandioca meal, which is largely used as food 

 by the artisan classes in Brazil. Bates noted that on these plunder- 

 ing expeditions there were always two classes of workers present 

 the small worker minors, who carried off the farinha grain by grain 

 in their jaws, and the large major workers with the huge smooth 

 heads, who apparently did nothing at all. 



The Ecitons or Foraging Ants of Brazil are fierce, carnivorous 

 insects, hunting their prey in large, well-organised armies. There 

 are two types of workers large-headed majors and small-headed 

 minors ; and in some species of Ecitons the large-headed workers 

 have very peculiar jaws, so greatly lengthened as to make it quite 

 impossible for them to do any work. These ants have no fixed 

 nest, but wander about from place to place in large armies and 

 form temporary resting-places, usually in hollow trees, where they 

 cluster together like a swarm of bees. There are several species 

 of Eciton Ants, some of which are quite blind ; these shun the 

 light, habitually moving along when on a hunting expedition 

 under fallen leaves, and when obliged to cross an open space 

 constructing temporary covered ways with granules of earth. In 

 other species the visual organs are partially or fully developed. 



The Driver Ants (Dorylides) of the Eastern hemisphere corre- 

 spond in many ways to the Ecitons, which are peculiar to the 

 New World. Like them, they are wanderers with no fixed place 

 of abode, and in many species the workers and females are totally 

 blind. In Western Africa the Driver Ants play the part of natural 

 scavengers. When on the march they attack all creeping insects 

 and small animals ; and devour all dead animal matter that may 

 come in their way. They will sometimes enter a house, and when 

 they leave it and pass on their way the house is most effectively 

 cleared of rats, mice, cockroaches, and vermin of all kinds. 



