THE Cows THAT ANTS MILK 17 



dation. The aphis wants to get rid of a trouble- 

 some waste product which is apt to clog it. The 

 ant wants to secure that waste product as a valuable 

 food-stuff. Hence, from all time, an offensive and 

 defensive alliance of the profoundest type has been 

 mutually struck up between ants and aphides. 

 How far this alliance has gone is truly wonderful. 

 The ants not merely " milk " the aphides, but actu- 

 ally collect them together in herds and keep them 

 in parks as domestic animals. Nay, more ; as Sir 

 John Lubbock has pointed out, different kinds of 

 ants domesticate different breeds of aphides, as each 

 is suited to the other's conditions. The common 

 black garden ant attends chiefly to the aphides 

 which frequent twigs and leaves, such as this very 

 rose-aphis for the black ant is a rover and a good 

 tree-climber ; he is much given to exploring ex- 

 peditions over the surface of plants in search of 

 honey, and he is not particular whether he happens 

 to gather it from flowers or from insects. The 

 brown ant, on the other hand, goes in rather for 

 such species of aphides as frequent the crannies 

 in the bark of trees ; while the little yellow ant, 

 an almost subterranean race, living underground 

 among the grass roots in meadows, " keeps flocks 

 and herds" (says Lubbock) "of the root-feeding 

 aphides." All these facts you can verify for your- 

 self with very little trouble. 



It is most interesting to watch a black ant on the 

 prowl after honey-dew. He is evidently led on to 

 the herd by smell, for he mounts the stem where 



