COMMUNITIES OP ANTS. 25 



ants thus associated together must have been enor- 

 mous. Even in single nests Forel estimates the 

 numbers at from five thousand to half a million. 



Ants also make for themselves roads. These are 

 not merely worn by the continued passage of the ants, 

 as has been supposed, but are actually prepared by 

 the ants, rather however by the removal of obstacles, 

 than by any actual construction, which would indeed 

 not be necessary, the weights to be carried being so 

 small. In some cases these roadways are arched over 

 with earth, so as to form covered ways. In others, the 

 ants excavate regular subterranean tunnels, sometimes 

 of considerable length. The Rev. Hamlet Clark even 

 assures us that he observed one in South America, which 

 passed under the river Parahyba at a place where it was 

 as broad as the Thames at London Bridge. I confess, 

 however, that I have my doubts as to this case, for I 

 do not understand how the continuity of the tunnel was 

 ascertained. 



The food of ants consists of insects, great numbers 

 of which they destroy ; of honey, honeydew, and fruit : 

 indeed, scarcely any animal or sweet substance comes 

 amiss to them. Some species, such, for instance, as 

 the small brown garden ant (Lasius niger, PI. I. fig. 1), 

 ascend bushes in search of aphides. The ant then 

 taj.s the aphis gently with her antenn.-p, and the aphis 

 emits a drop of sweet fluid, which the ant drinks. Some- 

 times the ants even build covered ways up to and over 

 the aphides, which, moreover, they protect from the 



