342 RECOGNITION OF FRIENDS AFTER A 
The difference of behaviour to friends and strangers 
was therefore most marked. 
The friends were gradually licked clean, and except 
for a few moments, and that probably by mistake, 
never attacked. The strangers, on the contrary, were 
not cleaned, were at once seized, were dragged about 
for hours with only a few minutes’ interval, by one, two, 
or three assailants. 
Though the above experiment seemed to me con- 
clusive, I thought it would be well to repeat it with 
another nest. 
I therefore separated a nest of Formica fusca into 
two portions on October 20, 1876. 
On February 25, 1877, at 8 a.m. I put an ant from 
the smaller lot back among her old companions. At 
8.30 she was quite comfortably established among them. 
At 9 ditto, at 12 ditto, and at 4 ditto. 
Jume 8.—I put two specimens from the smaller lot 
back as before among their old friends. At 1 they were 
all right and among the others. At2 ditto. After this 
I could not distinguish them amongst the rest; but they 
were certainly not attacked. 
June 9.—Put in two more at the same hour. Up 
to 3 in the afternoon they were neither of them attacked. 
On the contrary, two strangers from different nests, 
which I introduced at the same time, were both very 
soon attacked. 
July 14.—I put in two more of the friends at 10.15. 
In a few minutes they joined the others, and seemed 
quite at home. At 11 they were among the others 
At 12 ditto, and at 1 ditto. 
July 21.—At 10.15 I put in two more of the 
old friends. At 10.30 I looked; neither was being 
attacked. At 11 ditto, 12 ditto, 2 ditto, 4 ditto, and 
6 ditto. 
October 7.—At 9.30 I put in two, and watched 
them carefully till 1. They joined the other ants and 
