454 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



were many ants which did not engage in foraging at all (76 out of 195, 



or about 39 per cent), while only a few entered B a large part of the 

 possible number of times — only 8 out of 195, for example, taking ad- 

 vantage of more than half their opportunities. This suggests some 

 sort of division of labor, and thus agrees with Lubbock's ('82) observa- 

 tions, although the number of individuals which constantly engaged 

 in this activity was much larger in my studies than in his. This dif- 

 ference may have been due in part to our having used different species 

 of ants, but also in part to differences in our methods of experiment- 



30 



20 



ID 



30 



20 



10 



5' Z.5 3.5 4.5 S.5 E.5 7.5 B.5 

 52 47 14 6 4 2 I 



Figure 12. 

 (Foraging.) 



5 2.B 3.5 4i5 5.5 6J5 

 14 24- 7 2 



FiGUTtE 13. 



(Tending the Young.) 



Figure 14. 

 (Building.) 



ing and observing. His ants had perfect freedom to go to and from 

 the food, being therefore able immediately to return with food to their 

 fellows ; whereas mine had to wait for a longer or shorter time before 

 returning, in some cases probably nearly twenty-four hours, with the 

 result that those of my ants which entered the food-chamber were for 

 much of the time of no use as a source of food supply to the rest of 

 the colony, in consequence of which other ants probably went in search 

 of food, making the total number of food-seekers somewhat larger than 

 it would have been but for this restraint. His observations of unre- 

 strained ants were made once an hour ; mine, made on ants that were 

 free to enter the food chamber, but could not leave it, were made only 

 once a day. However, I do not think this wholly explains matters, 

 for on days immediately following those on which no record had been 

 taken, there were not many more foraging ants than after an interval 

 of only twenty-four hours, which seems to me to show that nearly all 

 individuals likely to frec^uent the food-chamber had done so during the 

 first twenty-four hours. Moreovp.r. the j^rfifif'inl b^atinc: of mv ants 



