EXPERIMENTS WITH PUPA, 131 
was not satisfied. I put in, therefore, two more at 
5 pM. At 5.30 they were all right; at 5.45, ditto, 
one being almost cleaned. At 6 one was all right; 
the other was no longer recognizable, having been quite 
cleaned. At 6.30 also one was quite at home; the 
other could not be distinguished. At 7 both had been 
completely cleaned 
The following day I marked another, and put her 
in at 6 am. At 6.15 she was all right among the 
others, and also at 6.30, 7, 7.30, 8, and 9.30, after 
which I could no longer distinguish her. 
Again, on the following day I put in another at 
6.45 am. At 7 she was quite at home, and also at 
7.15, 7.30, 8, and to 9.30, after which I did not watch 
her. 
To test the mode in which the ants of this nest 
would behave to a stranger, I then, though feeling no 
doubt as to the result, introduced one. The difference 
was very striking. The stranger was a powerful ant; 
still she was evidently uncomfortable, started away 
from every ant she met, and ran nervously about, 
trying to get out of the nest. She was, however, soon 
attacked. 
Again, on October 1 some pup of Lasius niger 
were placed in a glass with five ants from the same 
nest. 
On December 8 I tcok three of the ants which had 
emerged from these pups, and at midday put them 
back into their old nest, having marked them by nick« 
