TREATMENT OF STRANGERS. 125 
Lasius flavus (belonging to one of my nests of domesti- 
cated ants) had been feeding some hours previously, 
though none were there, or, indeed, out at all, at the 
moment. The entrance to the nest was about eight 
inches off; but she walked straight to it and into the 
nest. A second wandered about for four or five minutes, 
and then went in; a third, on the contrary, took a wrong 
direction, and, at any rate for three-quarters of an hour, 
did not find the entrance. 
At that time, however, I did not ascertain what 
became of the specimens thus introduced into a strange 
community. I thought it would be worth while to 
determine this, so I subsequently (1881) took six ants 
from one of my nests of L. flavus, marked them, and 
introduced them into another nest of the same species. 
As in the preceding cases they entered quite readily ; 
but though they were not at first attacked, they were 
evidently recognised as strangers. The others ex- 
amined them carefully, and at length they were all 
driven out of the nest. Their greater readiness to enter 
a strange nest may perhaps be accounted for by the fact 
that, as a subterranean species their instinct always is 
to conceal themselves underground, whereas, F’. fusca, 
a hunting species, does not do so except to enter its 
own nest.’ 
How do these ants and bees recognise their com- 
‘panions? The difficulty of believing that in such 
populous communities every individual knows every_ 
other by sight, has led some entomologists to suppose 
