16 Chapter I. 



stitution of ants 1 is in fact organic; it consists in the 

 descent from one fertile female, and in the differen- 

 tiation of the descendants into castes differing in 

 bodily and psychic qualities, as a result of the very 

 same specific fertility. The social bond, however, 

 which unites the members of an ant colony and sep- 

 arates them from other colonies of the same species, 

 is psychic and instinctive. It is the feeling of fellow- 

 ship, the instinct of sociality, resulting from common 

 descent ; it is, moreover, the instinct of imitation 

 which urges the workers of the same colony to act 

 in concert. This unity and co-operation is effected 

 by means of a certain sensile feeler language : by a 

 touch of their feelers thousands of members of a 

 colony immediately recognize one another as belong- 

 ing to the same community and effectually discover 

 the intruder ; by taps of their antennae they exchange 

 their feelings and perceptions and thus draw the 

 attention of other workers of their colony to the same 

 work. The same feeler language is also the means 

 of communication of ants in mixed colonies with their 

 auxiliaries of other species, and of genuine ant guests 

 with their hosts. 



This distinction between members of their own 

 colony and those of others is effected by very delicate 

 organs of smell 2 situated in the antennae. Members 



') We mean here in the first place the simple ant societies which 

 embrace no members of different species. 



2 ) We have already proven in our work, "Die psychischen Faehig- 

 keiten der Ameisen" ("Zoologica," 26th issue, p. 10-16), that there is 

 not merely question of a "chemical reflex" (as Bethe calls it), but of 

 a real sensitive perception. On the other hand, Lubbock's experiments 

 ("On the senses, instincts and intelligence of animals" [London, 1889], 

 p. 233 and foil.) have shown that an arbitrarily chosen sign or pass- 

 word is equally out of place, as is evident from the fact that an ant 

 which has lost its feelers is nevertheless recognized by her nest mates. 



