iv.] TENDENCY TO FOLLOW OLD TRACKS. 129 



course be little, if any, doubt, that bees are capable of 

 distinguishing colours ; but I have in my previous papers, 

 read before the Linnean Society, recorded some experi- 

 ments which put the matter beyond a doubt. Under 

 these circumstances, I have been naturally anxious 

 to ascertain, if possible, whether the same is the case 

 with ants. I have, however, found more difficulty 

 in doing so, because, as shown in the observations just 

 recorded, ants find their food so much more by smell 

 than by sight. 



I tried, for instance, placing food at the bottom of a 

 pillar of coloured paper, and then moving both the 

 pillar and the food. The pillar, however, did not seem to 

 help the ant (Lasius niger) at all to find her way to the 

 food. I then, as recorded in my previous paper, placed 

 the food on the top of a rod of wood 8 inches high, and 

 when the ant knew her way perfectly well to the food, so 

 that she went quite straight backwards and forwards 

 to the nest, I found that if I moved the pillar of wood 

 only 6 inches, the ant was quite bewildered, and 

 wandered about backwards and forwards, round and 

 round, and at last only found the pillar, as it were, 

 accidentally. 



Therefore, I could not apply to ants those tests which 

 had been used in the case of bees. At length, how- 

 ever, it occurred to me that I might utilize the dislike 

 which ants, when in their nests, have to light. Of course 

 they have no such feeling when they are out in search 

 of food ; but if light be let in upon their nests, they 

 at once hurry about in search of the darkest corners, 

 and there they all congregate. If, for instance, I un- 

 covered one of my nests and then placed an opaque 



K 



