INTEGRATION OF AGGREGATIONS 89 



culture media beat at different rhythms even when taken from the 

 same individual and kept as far as possible under identical cultural 

 conditions. When two such pieces succeeded, by outgrowths from 

 each, in estabHshing close organic union, the two beat in unison. 

 Such a modification of behavior may involve factors of transmission 

 distinct from those we usually regard as tactile. 



CONTACT AND ODOR INTEGRATION 



Sex recognition frequently causes animals to give characteristic 

 group reactions; often there are only two animals forming a diminu- 

 tive group. Sex recognition is frequently accomplished by contact 

 relations alone. Such behavior is recorded for crayfishes (Pearse, 

 1909; Andrews, 1910), spiders (Montgomery, 1910), frogs (Banta, 

 1 91 4), amphipods (Holmes, 1903), as well as others. 



Among other methods of sex recognition, that due to chemical 

 sense deserves prominent mention. This is well illustrated by the 

 long distances certain male moths will fly to cluster about a female 

 ready to copulate (Kennedy, 1927). Animals may aggregate at other 

 times than the breeding season, due to the same sort of stimulus; 

 and this stimulus is also frequently eft'ective in maintaining the 

 aggregations once formed. In fact, it is common for the principal 

 stimulus causing animals to congregate to be the effective one in in- 

 tegrating their aggregation. 



These two senses, odor and contact, are sufficient means of group 

 integration to form the basis of well-unified societies. Much of the 

 social organization of the ants and the termites appears to be based 

 on them. The ants apparently live in a world of contact-odor shapes, 

 as we live primarily in a world of color-shapes (Wheeler, 1913a). 



VISUAL INTEGRATION 



Sight plays an important role in the organization of many animal 

 groups. When one vulture, soaring aloft, sees another swoop miles 

 away, he moves over and also swoops; his action is seen by others, 

 and thus these scavenger groups congregate rapidly, although they 

 are practically lacking in a sense of smell. 



Aggregations of male frogs in the breeding season will follow and 



