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 ' iastitution 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. rufharbis ; 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 ia 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 iateresting paper on this subject we acknow- 

 ledge our great indebtedness, writes : — 



" It has been most clearly shown by many observers 

 that, a 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. Eeplace 

 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, 



