HARVESTING ANTS. 87 



It seems difficult to understand how it comes that 

 these galls are systematically placed among the 

 seeds, for it was evidentl}^ no chance occurrence, and 

 I can only conjecture that the worker ants may have 

 brought them in and stored them under the impres- 

 sion that they were really seeds ! Even ants make 

 mistakes, and of this I have given an example above 

 (p. 19). Though I have frequently found colonies of 

 several distinct species of ants inhabiting nests made in 

 the earth traversed b}^ the widespread galleries of Atta 

 strudor and barbara, I have never detected any inter- 

 mixture of species in the chambers of a nest,* and but 

 rarely found even the galleries and entrance used in 

 common by more than one species. On one occasion 

 when opening a nest of structor I cut through a 

 colony of the tiny, large-headed, yellow ant Fheidole 

 mcr/acejjJiala, lying in the midst of, though distinct 

 from, the former. AVhen, however, it chanced that 

 one of the sfructors fell from the crumbling earth 

 into the midst of the P/ieidoIes, it was curious to see 

 how fiercely it would be attacked, and with what 

 terrified speed it would scamper off, without attempt- 

 ing any resistance, and often carrying two or three 

 Fheidohs haniicino: on to its leg's. 



Accidentally in this way battles do sometimes take 

 place between ants of different species ; but by far 

 the most savage and prolonged contests which I 

 have witnessed were those in which the combat- 

 ants belong to two different colonies of the same 

 species. 



* Except in a few cases wbere I have seen one or two structors in nests of 

 harhara and viceversd, and in the curious instance to be mentioned below, 

 where one colony cousisted of nearly equal parts of structor, iarbara, and the 

 red-headed variety of barbara. 



