54 On the Habits of Ants. 



longer distinguish the friends. They were however certainly 

 not attacked. The strang-er, on the contrary, was killed and 

 brought out of the uest. 



This case, therefore, entirely confirmed the preceding ; while 

 strangers were always attacked, friends were amicably received, even 

 after a year of separation. 



Thus therefore, in these experiments, as in those previously re- 

 corded, the old acquaintances were evidently recognised. This is 

 clear, because they were never attacked, while any ant from a 

 different nest, even of the same species, would be set on and killed, 

 if she did not succeed in escaping from the nest. This recognition of 

 old friends is the more remarkable, because, in one case, the ants 

 had not seen each other for more than a year. 



To test their intelligence I made the following experiment. I 

 placed some honey suspended over the nest at a height of about 

 half-an-inch, and accessible only by a paper bridge more than ten 

 feet long. Under the glass I then placed a small heap of earth. 

 The ants soon swarmed over the earth on to the glass and began 

 feeding on the honey. I then removed a little of the earth, so that 

 there was an interval of about one- third of an inch between the glass 

 and the earth — but though the distance was so small they would 

 not jump down, but preferred to go round by the long bridge. They 

 tried in vain to stretch up from the earth to the glass, which how- 

 ever was just out of their reach, though they could even touch it 

 with their antenna? ; but it did not occur to them to heap the earth 

 up a little, though if they had moved only half-a-dozen particles of 

 earth they would have secured for themselves direct access to the 

 food. This however never suggested itself to them. At length they 

 gave up all attempt to reach up to the glass and went round by the 

 paper bridge. I left the arrangement for several weeks, but they 

 continued to go round by the long paper bridge. 



It is remarkable that notwithstanding the labors of so many ex- 

 cellent observers, and though ants' nests swarm in every field and 

 every wood, we do not yet know how their nests commence. 



Three principal modes have been suggested : — After the marriage 

 flight the young queen may either 



