v SOCIAL LIFE OF ANIMALS 87 



anti-social ' art of war," sometimes against other com- 

 munities of the same species, sometimes with other kinds. 

 Their battles," Kirby says, " have long been celebrated ; 

 and the date of them, as if it were an event of the first 

 importance, has been formally recorded." ^Eneas Sylvius, 

 after giving a very circumstantial account of one con- 

 tested with great obstinacy between a large and small 

 species on the trunk of a pear tree, gravely states, ' ' This 

 action was fought in the pontificate of Eugenius IV., in 

 the presence of Nicholas Pistoriensis, an eminent lawyer, 

 who related the whole history of the battle with 

 the greatest fidelity." In the fray the combatants 

 are thoroughly absorbed, yet at a little distance other 

 workers are uninterruptedly treading their daily paths ; 

 the melee is intense, yet every ant seems to know those 

 of its own party ; the result of it all is often nothing. 

 We laugh at the ants the laugh conies back on our- 

 selves. 



In some cases an expedition has the definite end of 

 slave-making, as is known to be true of Formica san- 

 guinea -a British species, and of Polyergus rufescens, 

 found on the Continent. The former captures the larvae 

 of Formica fusca, carries them home, and owns them 

 henceforth as well-treated slaves ; while the Amazon 

 Ant (Polyergus) draws its supply from both F. jusca and 

 F. cunicularia, and comes to depend very largely on its 

 captives. While the Amazon ants can fend for themselves 

 if they choose, there are other slave-keeping species which 

 can neither procure food nor use it apart from their 

 dependents. Sir John Lubbock (Lord Avebury) noted 

 that every transition exists between bold and active 

 baron-like marauders and enervated masters, who are 

 virtually helpless parasites upon their slaves a sugges- 

 tive illustration of laziness outwitting itself. 



Slaves somewhat painfully suggest domesticated 

 animals, and these are also to be found among ants. 

 For what Linnaeus said long ago, that the ants went up 

 trees to " milk their cows, the Aphides," is true. Certain 

 species of ants tickle the plant-lice with their antenna?, 

 and lick the juice which oozes from them ; nay, more, 



