212 JOHN L. PRICER. 



ants which were in the feeding-room would not hesitate to pass 

 through it, but they would invariably try to walk on the side 

 which was lowermost when in the usual position. 



Experiment III. 



I have repeatedly taken a stick and made a narrow mark in 

 the earth across the path of the ants from the nest to the aphid 

 tree and have observed that only very few of the ants going from 

 the nest to the aphid tree seem to notice it, while nearly all those 

 going in the opposite direction would stop and examine the mark 

 carefully for some time, and some would return to the aphid tree 

 rather than cross the mark. 



These experiments show clearly that the ants behave differently 

 when traveling from the nest than when returning to it. They 

 are seemingly willing to venture into new territory when travel- 

 ing away from the nest, because of something akin to a con- 

 sciousness that they can at any time retrace their steps and find 

 the nest, while when traveling toward the nest the link is broken 

 when the surface of the earth is disturbed across their path. 

 This may be either because the continuity of the outgoing trail is 

 destroyed, or because the appearance of things with which they 

 are familiar is altered. 



Observation 2 seems to indicate quite strongly that these ants 

 possess a sense of direction and an unusual power of using it 

 under unfavorable circumstances. The rough ground all matted 

 with weeds must have appeared to them much as a mountain 

 region over which a cyclone had torn the forest to shreds would 

 appear to us, and yet they made a straight path across it in the 

 darkness. Their determination to cross this hazardous region at 

 once seems also to imply that had some realization of the inter- 

 ests at stake and some memory of the direction in which the 

 goal lay. 



Experiment IV. 



A Fielde nest containing a large colony of C. pennsylvanicns 

 was connected with a feeding-room by means of a system of four 

 glass tubes, each one half inch in diameter. One of these tubes 

 was straight, another was bent into a vertical loop, another into 

 a horizontal loop, and the fourth was arched so as to form a steep 



