RECOGNITION OF FRIENDS. 321 
The observation recorded by Huber was made 
casually, and he did not take any steps to test it by 
subsequent experiments. The fact, however, is of 
so much importance that I determined to make 
further observations on the subject. In the first place, 
I may repeat that I have satisfied myself by many 
experiments, that ants from one community introduced 
into another,—always be it understood of the same 
species,—are attacked, and either driven out or killed. 
It follows, therefore, that as within the nest the most 
complete harmony prevails—indeed, I have never seen 
a quarrel between sister ants—they must by some means 
recognise one another. 
When we consider their immense numbers this is 
sufficiently surprising ; but that they should recognise 
one another, as stated by Huber, after a separation of 
months, is still more astonishing. 
I determined therefore to repeat and extend his 
observations. 
Accordingly, on August 20, 1875, I divided a colony 
of Myrmica ruginodis, so that one half were in one 
nest, A, and the other half in another, B, and were 
kept entirely apart. 
On October 3, I put into nest B a stranger and 
an old companion from nest A. They were marked 
with a spot of colour. One of them immediately 
flew at the stranger; of the friend they took no 
notice. 
October 18.—At 10 a.m. I put in a stranger and a 
7 
