40 HARVESTING ANTS. 



carried on tlie reverse journey into the lower and 

 plundered nest. 



Thus when I fixed my attention on one of these 

 robbed ants surreptitiously making its exit with the 

 seed from the thieves' nest, and having overcome the 

 opposition and dangers met with on its way, reaching 

 after a journey which took six minutes to accomplish, 

 the entrance to its own home, I saw that it was 

 violently deprived of its burden by a guard of ants 

 stationed there apparently for the purpose, one of 

 whom instantly started off and carried the seed all 

 the way back again to the upper nest. 



This I saw repeated several times. 



After March 4 I never saw any acts of hostility 

 between these nests, though the robbed nest was not 

 abandoned. In another case of the same kind, how- 

 ever, where the struggle lasted thirty-one days, the 

 robbed nest was at length completely abandoned, and 

 on opening it I found all the granaries empty with one 

 single exception, and this one was pierced by tlie 

 matted roots of grasses and other plants, and must 

 therefore have been long neglected by the ants. 

 Strangely enough, not one of the seeds in this de- 

 serted granary showed traces of germination. 



No doubt some very pressing need is the cause of 

 these sj^stematic raids in searcli of accumulations of 

 seeds, and there can be little doubt that the require- 

 ments of distinct colonies of ants of the same species 

 are often different even at the same season and date. 

 Thus these warring colonies of ants were active on 

 many days when the majority of the nests were com- 

 pletely closed ; and I have even seen these robbers 

 staggering along, enfeebled by the cold, and in wind 

 and rain, when all other ants were safe below ground. 



