EXPEEIMENTS WITH PUP^ 131 



was not satisfied. I put in, therefore, two more at 

 5 P.M. 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 a.m. 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 A.M. 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 pupae of Lasius niger 

 were placed in a glass with five ants from the same 

 nest. 



On December 8 I took three of the ants which had 

 emerged from these pupae, and at midday put them 

 back into their old nest, having marked them by nick- 



K 3 



