INSECTA 121 



soon as the youngsters mature, however, she does no more 

 work, but is fed and kept clean by them. 



The large red mound-building ant, Formica rufa, found 

 in various parts of the United States, commonly enslaves 

 other species. A suitable nest is located in advance and 

 the whole colony raids it killing the soldiers and carrying 

 away the workers, larvse and pupae. Some tropical ants 

 are so dependent upon slaves that they are not even able 

 to feed themselves. The harvesting ants collect certain 

 seeds which they husk, dry, and store in little underground 

 granaries. 



The complex communities of ants all center about the 

 queen. She is always guarded, cleaned, and fed with great 

 care. She must be kept in good condition, for the con- 

 tinued existence of the colony depends upon her ability to 

 lay eggs. The males are of no service to the community 

 except to fertilize the queen. The workers carry on all 

 general activities. They gather food and feed each other, 

 fight, dig, gnaw, clean, nurse, etc. The instinct to re- 

 gurgitate food from the crop to feed other ants is strongly 

 developed and is probably largely responsible for the 

 extreme development of castes among ants. It makes it 

 possible for one caste to do all the food collecting and feed- 

 ing, while other individuals become specialized for other 

 occupations. 



Yet, notwithstanding the complex activities of ants, 

 they have little " intelligence." They follow their in- 

 stincts slavishly and are not able to solve the simplest 

 problems. Different individuals of a colony recognize each 

 other largely by odor. Experiments have been performed 

 in which strange ants were smeared over with the extract 

 from the bodies of certain individuals from a particular 

 colony. When these disguised individuals were put in the 

 nest from which their odor came, they \vere received as 

 friends. In another experiment an ant was taken from 

 a nest and its odor was washed off. On being returned to 

 its own nest, it was seized and torn to pieces. 



