iv.] DIVISION OF LABOUR. 137 



again on the llth December, but with these two excep- 

 tions, the whole of the supplies were carried in by Nos. 

 5 and 6, with a little help from No. 7. 



Thinking now it might be alleged that possibly these 

 were merely unusually active and greedy individuals, I 

 imprisoned No. 6, when she came out to feed on the 5th. 

 As will be seen from the table, no other ant had been out 

 to the honey for some days; and it could therefore 

 hardly be accidental that on that very evening another 

 ant (then registered as No. 9) came out for food. This 

 ant then took the place of No. 6, and (No. 5 being 

 imprisoned on the llth January) took in all the 

 supplies, again with a little help from No. 7. So 

 matters continued till the 17th, when I imprisoned 

 No. 9, and then again, i.e. on the 19th, another ant 

 (No. 10) came out for the food, aided on and after the 

 22nd by another, No. 11. This seems to me very 

 curious. From the 1 st November to the 5th January, 

 with two or three casual exceptions, the whole of the 

 supplies were carried in by three ants, one of whom, 

 however, did comparatively little. The other two were 

 imprisoned, and then, but not till then, a fresh ant 

 appeared on the scene. She carried in the food for a 

 week, and then, she being imprisoned, two others under- 

 took the task. On the other hand, in Nest 1, where the 

 first foragers were not imprisoned, they continued during 

 the whole time to carry the necessary supplies. The 

 facts therefore certainly seem to indicate that certain 

 ants are told off as foragers, and that during winter, when 

 but little food is required, two or three are sufficient to 

 provide it. 



I have already mentioned that while Lasius niger, the 



