LIFE HISTORY OF CARPENTER ANT. 211 



Experiment I. 

 December 24, 1906, I connected a Fielde nest containing a 

 colony of C. pennsylvanicus with a feeding-room by means of a 

 series of five glass tubes, each about six inches long. Five days 

 later, when the ants had become accustomed to these tubes, I 

 turned one of the sections of the tube end for end and ants passed 

 through in both directions without seeming to notice the change. 

 Next I removed one of the sections and replaced it with a new 

 piece of tubing of the same size. At this time three workers 

 were in the feeding-room, and soon one of them started to go to 

 the nest. She went hurrying along the tube until she came to 

 the new section, when she suddenly stopped and began feeling 

 cautiously about. She then made several trips to the feeding- 

 room and back to the new section, but did not venture a full 

 length into it. While she was continuing in this way another 

 worker came from the nest and she too came to a sudden stop 

 on reaching the new section of the tube. She examined it care- 

 fully and then, without returning to the nest, proceeded cautiously 

 through it. Here she met her friend who had formerly discovered 

 the change, and after they had exchanged antennal greetings, 

 the two returned to the nest. This experiment was repeated a 

 number of times and always with the same results, that is, those 

 ants which were in the feeding-room always refused to cross the 

 new section until they had met some friends directly from the 

 nest, while those coming directly from the nest always crossed 

 the new section, at least, after making one trip back to the nest. 



Experiment II. 

 The same nest as above was connected with the feeding-room 

 by means of a glass tube four feet long which had been bent at 

 the center to form an angle of about 1 io°. The ends were bent 

 in the opposite direction, so that by slipping the ends of this tube 

 over the smaller tubes which led from the nest and feeding-room 

 respectively, and by rotating the larger tube about the smaller 

 ones as axes, I could vary the elevation over which the ants must 

 travel in passing from nest to feeding-room. The tube was 

 allowed to lie flat on the table usually, and at intervals I would 

 raise it up so as to cause a steep incline. When this was done 



