COMMUNICATION AMONG INSECTS — McINDOO 561 



analyzes a chord. In this respect, if not in the variety of smells, we 

 are able to distinguish, our olfactory sense has degenerated. 



It is well known among beekeepers that bees can easily distinguish 

 the body odors of a person. Usually beekeepers, when handling 

 queenbees, hold them gently and as' little as possible wdth the fingers, 

 because they know by experience that the workers do not like the 

 odor from the fingers, and often kill queens excessivelj^ charged with 

 foreign odor, such as that from perspiration. The writer discovered- 

 that a friendly hive mate can easily be changed to a strange worker 

 by merely stroking its back with a finger. 



The homing and orientation of ants have for ages puzzled the minds 

 of observers. There are really two problems in^'olved. First, how 

 does a solitary forager, after she has found food at the end of a long 

 and raiiibling course, find her way back to the nest? Second, how do 

 ants follow a well-beaten ant trail to and from the nest? Many 

 theories have been advanced to answer these questions. Chief among 

 them are the following: 



Pieron divides ants into three divisions; some follow the trail by 

 smell, some by sight, and others by a kind of muscular sense. In 

 some species there is a kind of muscular memory, the ants simply 

 reversing on the homeward path all the turnings they took on the way 

 out, like a top unwinding itself. Cornetz believes that ants have a 

 mysterious power of registering in their bodies the general direction 

 of their outward course and reversing it when they have found a 

 load to be carried home. The ant behaves, in short, as if she con- 

 tained a compass. This kinesthetic sense acts merely like a roughly 

 constructed pedometer, giving the insect a vague notion of the dis- 

 tance traveled from the nest. Many writers claim that in part, if 

 not entirely, ants are guided by sight in their wanderings and along 

 the trails. 



Brun gives the best and most complete general survey of the entire 

 subject of orientation in insects, birds, mammals, and man. In 

 regard to ants he strongly advocates the theory that they are guided 

 by contact and by odors, although he fully discusses the various other 

 factors involved. As to distant orientation in ants, he admits to 

 consideration only the contact-odor sense and the sense of sight. He 

 states that the faculty of self-orientation is in its broadest sense a 

 primary property of living protoplasm. The higher ants are able 

 to see the large distant objects which serve them as landmarks for 

 finding their nests, and in a certain measure this faculty ajDpears to 

 serve the lower ants. The higher ants, by folloAving a straight course 

 from their nest, are able upon returning to deviate to the right or 

 left, thus sometimes describing a polygon during their wanderings, 

 but they do not possess a sense of angles, as suggested by a few 

 writers. In the higher species a true associative memory of location 



