HA R VESTIXG A NTS. 59 



of distinct species, tend to show tliat, even as things 

 are, the}'" frequently have to fight for their food. 



Hitherto, as far as I have been able to learn, only 

 nineteen true harvesting ants have been detected in 

 the whole world, limiting this term to those species 

 which make the collection of seeds the principal occu- 

 pation of their outdoor lives, and are evidently in the 

 main dependent upon this kind of food for subsis- 

 tence. 



Now if we compare these nineteen species of ants* 

 together a very curious fact forces itself upon our 

 notice — namely, that all of them are closely related, 

 so much so that not only do all belong to the same 

 division of ants (the tribe MyrmicinecB), but that with 

 one exception {Pseudou/t/rma) all would have been 

 jDlaced by the great Fabricius in one genus, Atfa, and 

 the one exception is not far removed from it. 



We must not forget, however, that, as has been 

 stated, there are other ants which do occasionally 

 collect seeds, and thus appear to show traces of this 

 remarkable instinct ; but as far as I have yet seen, it 

 is always possible to distinguish them readily from true 

 harvesters. Still I think it verj^ likely that in hot 

 climates the division between harvesters and non- 

 harvesters may be bridged over by a complete chain 

 of intermediates. Here two more questions suggest 

 themselves for more complete future solution. (1) 

 Do true harvesters which store seed in granaries ever 



* These 2ire Myrmica (Atta) harhata, from Texas and Mexico; (Ecohma 

 {Atta) cephalotcs, fiom Brazil and Mexico ; CEcodoina (Atfa) proridens, from 

 India ; (Ecodoma (Atta) dijusa, from India; Atta rufa, from India; Pheidole 

 {^Atia) megacephala, from South France; Atta harbara, from South France, 

 Capri, and Algiers ; Atta structor, from South France; and Fseiidomyrma 

 ru/oni(/ra, from India. 



