84 ON THE HABITS OF ANTS. [user. 



I supplied one of my ant-nests of Lasius flavus with a 

 frame, containing, instead of earth, a piece of linen, one 

 portion of which projected beyond the frame, and was 

 immersed in water. The linen sucked up the water by 

 capillary attraction, and thus the air in the frame was 

 kept moist. The ants approved of this arrangement, 

 and took up their quarters in the frame. To minimize 

 evaporation, I usually closed the frames all round, leaving 

 only one or two small openings, for the ants, but in this 

 case I left the outer side of the frame open. The ants, 

 however, did not like being thus exposed ; they therefore 

 brought earth from some little distance, and built up a 

 regular wall along the open side, blocking up the space 

 .between the upper and lower plates of glass, and leaving 

 only one or two small openings for themselves. This 

 struck me as very ingenious. The same expedient was, 

 moreover, repeated under similar circumstances by the 

 slaves belonging to my nest of Polyergus. 



I have also made many experiments on the power 

 possessed by ants of remembering their friends. It will 

 be recollected that Huber gives a most interesting ac- 

 count of the behaviour of some ants, which, after being 

 separated for four months, when brought together again, 

 immediately recognized one another, and " fell to mutual 

 caresses with their antennae." Forel, however, regards 

 these movements as having indicated fear and surprise 

 rather than affection, though he also is quite inclined to 

 believe, from his own observation, that ants would re- 

 cognize one another, after a separation of some months. 

 The observation recorded by Huber was made casually .; 

 and neither he nor any one else seems to have taken any 

 steps to test it by subsequent experiments. The fact is 



