THE WEB OF LIFE 355 



ever, the slaves gradually decrease in number, and the 

 mixed colony becomes a pure red colony. In this case, 

 therefore, the slave-keeping need not be more than tempor- 

 ary. In fact, Prof. Wheeler has shown that the largest 

 American colonies of Formica sanguinea are very often 

 pure. 



In the Amazon ants (e.g. Polyergus rufescens in Europe 

 and P. lucidus in America) the ' institution of slavery ' has 

 developed, and there are probably no slaveless colonies. 

 A fertilized queen is accepted by some queenless colony of 

 Formica fusca or F. rufibarbis ; her offspring are tended 

 and become dominant ; and the number of slaves is sus- 

 tained or increased by slave-capturing raids. Forel calcu- 

 lated that a single colony may capture in the course of 

 one summer as many as forty thousand larvae and pupae of 

 slaves who grow up to do everything for their masters, 

 just as if these were their own kith and kin. For the 

 Amazons can do nothing but raid ; their mandibles have 

 become sabres quite unsuited for humble toil ; they cannot 

 dig, but to beg they are not ashamed. Dr. Louis Dublin, 

 to whose interesting paper on this subject we acknow- 

 ledge our great indebtedness, writes : 



" It has been most clearly shown by many observers 

 that, if left for as short a period as two or three days with- 

 out the aid of their slaves they would starve to death, 

 even if surrounded with an abundance of food. Replace 

 the black ants and the scene changes immediately ; the 

 Amazons take new courage and are soon fed with the 

 regurgitated food which the slaves are only too eager to 

 offer them." 



In a sense, then, the tables have been turned, and the 

 slaves are the masters. The Amazons fight and reproduce, 



