COMMUNITIES OF 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 was supposed by Christ, 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, Pl. I. fig. 1), 
ascend bushes in search of aphides. The ant then 
taps the aphis gently with her antenne, 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 
3 
