EXPEEIMENTS WITH INJOXICATED ANTS. 233 



It may be remembered that my nests have enabled 

 me to keep ants under observation for long periods, and 

 that I have thus identified workers of Lasius niger and 

 Formica fusca which were at least seven years old, but 

 my oldest ants have been two queens of Formica fuscay 

 which I took in a nest in December, 1874. They must 

 then have been nine months old, and of course may 

 have been more. One of these queens, after ailing 

 for some days, died on July 80, 1887. She must 

 then have been more than thirteen years old. I was 

 at first afraid that the other one might be affected by 

 the death of her companion. She is, however, still 

 alive (May, 1888), and, though a little stiff in the 

 joints, as far as I can judge, in her usual health. 

 Still, there are only a few queens in a nest, and no 

 doubt the majority of the workers, at least in the 

 summer and when the community is most active, are 

 very young, which adds greatly to the difficulty of sup- 

 posing that they are personally known to one another. 



It has been suggested that each nest has, perhaps* 

 a special signal or pass-word. To test this I took, as I 

 have already mentioned in my book on " Ants, Bees, and 

 Wasps," a number of ants, half from one nest and half 

 from another, and made them very drunk, so as to be 

 thoroughly insensible. I then marked them with spots 

 of different colours, so as to distinguish the two lots, 

 and put them on a table near where some ants belonging 

 to the nest from which one half of them had been 

 taken, were feeding on some honey. The table was 

 surrounded by a moat containing water to prevent the 

 ants from wandering away. The sober ants were rather 

 puzzled; but, after examining the intoxicated individuals, 

 they picked up the strangers and threw them into the 



