Hillside. 169 



have found out the advantages of " honey dew " as a food. 

 They do not, however, care to go in search of it, but prefer 

 keeping the aphides near their nests, and for this purpose 

 collect them from a distance, and place them where they can 

 be frequently visited. When an ant wants some honey 

 dew it strokes the body of the aphis gently with its antennae, 

 and this soon causes the aphis to lift up its body and excrete 

 a drop of the limpid juice. Many naturalists have tried to 

 copy the actions of the ant and, as it were, artificially to 

 cause the aphides to excrete, but they have never been 

 successful. The excreted matter is a waste product in the 

 economy of the aphis, and sooner or later has to be got rid 

 of; but the ant appears to be able to secure its discharge at 

 will. 



It is very remarkable, too, how readily ants are able to 

 discriminate between members of their own and members of 

 other colonies. Even when the eggs of one species are 

 hatched in the nest of another, they are at once known to be 

 intruders, whilst if members of their own nest are removed 

 for a time, and then returned to the nest, they are at once 

 recognised as friends and relations. 



Perhaps in no way have ants shown their intelligence in 

 communicating with each other more than in their forays and 

 battles with other ants. An American observer records that 

 whilst watching a battle between Lasius niger, a black, and 

 Lasiusflavus, a yellow species, he frequently saw the yellow 

 ones drop to the rear for refreshments, whilst on the same 

 side a special body of ants were told off to look after the 

 wounded, forming, as it were, a kind of ambulance corps. 

 The yellow ants frequently sent back for reinforcements, and 

 at last drove off the invading black ants, who had attempted 



