RECOGNITION OF FRIENDS. 



413 



Lasius niger containing a large number of pupae. 

 Some of these I placed by themselves in charge of 

 three ants belonging to the same species, and taken 

 from a nest which I have had under observation for 

 rather more than ten years. On August 28, I took 

 twelve of the young ants, which in the meantime had 

 emerged from the separated pupae, selecting some 

 which had all but acquired their full colour. Four of 

 them I replaced in their old nest, and four in that from 

 which their nurses were taken. 



At 4.30. In their own nest none were attacked. 



In their nurses' nest one was attacked. 

 5. In their own nest none were attacked. 



In their nurses' nest all four were attacked. 

 8. In their own nest none were attacked. 



In their nurses' nest three were attacked. 



The next day I took six more and marked them 

 with a spot of paint as usual, and at 7.30 replaced them 

 in their own nest. 



At 8 



8.30 



9 



10 

 11 

 12 



1 



4 



7 



9 



I found 5 quite at home. The others I could 



not see, but none 

 were attacked. 



,. 3 



The next morning I could only see two, but none 

 were being attacked and there were no dead ones. It 

 is probable that the paint had been cleaned off the 

 others, but it was not easy to find them, all among so 



