MUTUAL AID AND COMMUNAL LIFE AMONG ANIMALS 393 



the branch on which the plant lice are gets withered and dry, 

 the ants have been observed to carry the plant lice carefully 

 to a fresh, green branch. On page 374 is described how the 

 little brown ant Las-ius brunneus cares for the corn root plant 

 louse. In the arid lands of New Mexico and Arizona the ants 

 rear their scale insects on the roots of cactus. Other kinds of 

 ants carry plant lice into their nests and provide them with food 

 there. Because the ants ob- 

 tain food from the plant lice 

 and take care of them, the 

 plant lice are not inaptly 

 called the ants' cattle. 



Like the honeybees, the 

 young ants are helpless 

 little grubs or larvae, and 

 are cared for and fed by 

 nurses. The so-called ants' 

 eggs, little white, oval 

 masses, which we often 

 see being carried in the 

 mouths of ants in and out 

 of ants' nests, are not eggs, 

 but are the pupae which 

 are being brought out to 

 enjoy the warmth and light 

 of the sun or being taken 

 back into the nest after- 

 wards. 



In addition to the workers that build the nest and collect 

 food and care for the plant lice, there is in many species of 

 ants a kind of individuals called soldiers. These are wingless, 

 like the workers, and are also, like the workers, not capable of 

 laying or of fertilizing eggs. It is the business of the soldiers, 

 as their name suggests, to fight. They protect the community 

 by attacking and driving away predaceous insects, especially 

 other ants. The ants are among the most warlike of insects. 

 The soldiers of a community of one species of ant often sally 

 forth and attack a community of some other species. If suc- 

 cessful in battle the workers of the victorious community take 

 possession of the food stores of the conquered and carry them 

 to their own nest. Indeed, they go even further; they may 



FIG. 246. Nest of the ant, Leptothorax emer- 

 soni, with the nest of another ant, Myrmica 

 scabrinodes. (See account on page 375.) 

 (After Wheeler.) 



