278 LIFE AND HER CHILDREN. 
It will be remembered (see p. 203) that the 
aphides plunge their trunks into plants, and suck all 
day long, filling their bodies with juice. Now, when 
the ant comes running up the stem in search of 
food, she comes behind the aphis and strokes it 
gently with her antennae, and the little creature 
gives out from the end of its body (or sometimes from 
the little horns), a drop of sweet liquid which the 
ant licks up, and it is probable that this is pleasant 
to the aphis, which in any case always gives out 
juice from time to time. The ant, on her side, pro- 
tects these plant-lice, keeping off the lady-birds or 
other insects, which might attack them, and even 
taking care that, for a certain distance round her 
own nest no ant from a strange community shall 
poach upon her grounds. 
And now, as these well-fed ants, with their crops 
filled with two or three drops of aphis juice, hurry 
home again they meet with others, those that have 
been collecting leaves, or those which have been 
sweeping out the galleries of the nest, and have had 
no time to get food. These hungry ants run up to the 
full-fed ones, and stroke them with their antennas, 
asking for food, and then lifting up their mouth, they 
receive the juice which the others squeeze out of 
their crop ; for one of the principal rules in ant-cities 
is for every member to help another for the general 
good. 
Busy, however, as every one seems to be outside 
the nest, they are still busier within. If you could cut 
one of these ant-hills in half downwards, you would 
find that the nest extends often a foot or more into 
the earth, and everywhere it is a maze of narrow 
