BUCKINGHAM. — DIVISION OF LABOR AMONG ANTS. 471 



large, large, small, and very small, but none of them were so small as 

 those of C. americanus, which had been previously used. The mounted 

 ants, arranged in series for each occupation according to colonies, were 

 then compared colony with colony, keeping in mind the size of the 

 original out-door colony from which they were captured. It was found 

 that in regard to foraging, the sorts of individuals were practically the 

 same, irrespertive of the size of the colony. There was, however, this 

 difference in behavior, that the large colonies sent proportionately more 

 workers into the field, probably because large colonies are apt to be less 

 timid than small ones. Forel (74, p. 249) has also noticed this fact. 



While also proportionally more ants were active in tending the 

 young in the large colonies, I failed to find any correlation between 

 the size of the workers engaged in this activity and the numbers in the 

 colony. In tending the young under excitement and in responding to 

 disturbances, there were hardly any ants from small colonies, so that a 

 comparison between large and small colonies could not be made for 

 these activities. So few ants were seen bringing in food that it was 

 impossible to ascertain whether such correlation exists in that activity 

 or not. As it does not, however, exist in ants seen in the field, when 

 those without food are considered together, it is highly probable that 

 it is also wanting here. In carrying other ants, in being carried by 

 other ants, and in carrying earth, no correlation was found. 



Of course it must be remembered that, — as Wheeler (:02) found in 

 Pheidole and Pricer (:08) in certain species of Camponotus, — in colo- 

 nies which are extremely small because of poor nourishment, due to 

 the youth of the colony or to other causes, there are no large workers, 

 or at most only a few, and hence all the duties must be performed by 

 the small ants. My remarks in regard to lack of correlation between 

 the size of the colony and the sorts of ants engaged in various activities 

 would therefore apply only to such colonies as have all the sizes which 

 are normal to them. Also, there are, in proportion to the whole num- 

 ber of active ants, rather fewer large ants engaged in most of the activ- 

 ities in these wild colonies than in the small colonies in artificial nests 

 described above. 



iii. Correlation between Age and Function. 



1. Methods. — When an ant emerges from the pupal state it is very 

 light in color, but begins almost immediately to grow darker, taking, 

 according to the species, a longer or shorter time to reach its ultimate 

 color tone. McCook ('79, p. 20), Forel ('74, p. 262), P^rez (:00, p. 769), 

 and Mceno (:00) claim that ants, when they first emerge, do not go 

 out or fight, but attend to duties within the nost. That there is some 



