11 ON ANIMAL LIFE 69 



course be useless. The workers do not, except 

 occasionally, lay eggs, but carry on all the af- 

 fairs of the community. Some of them, and 

 especially the younger ones, remain in the 

 nest, excavate chambers and tunnels, and tend 

 the young, which are sorted up according to 

 age, so that my nests often had the appear- 

 ance of a school, with the children arranged 

 in classes. 



In our English Ants the workers in each 

 species are all similar except in size, but 

 among foreign species there are some in which 

 there are two or even more classes of workers, 

 differing greatly not only in size, but also in 

 form. The differences are not the result of 

 age, nor of race, but are adaptations to 

 different functions, the nature of which, 

 however, is not yet well understood. Among 

 the Termites those of one class certainly seem 

 to act as soldiers, and among the true Ants 

 also some have comparatively immense heads 

 and powerful jaws. It is doubtful, however, 

 whether they form a real army. Bates 

 observed that on a foraging expedition the 

 large-headed individuals did not walk in the 



