BUCKINGHAM. — DIVISION OF LABOR AMONG ANTS. 451 



42, 51, 53, 54, 55). Usually the three-series set embraced two series 

 with the food in B and one with the food in A, but in one instance 

 (colony 24) the reverse was true, two series of observations having been 

 made with food in ^1, and only one with food in li. These three series 

 were so arranged as to eliminate as far as possible any tendency of the 

 colony to a change in its activities during several weeks of observation, 

 by putting one of the two series before, the other after the odd series. 

 Although the results may differ considerably in different experiments, 

 and the proportions found may be so variable as to show that we are 

 dealing with rough approximations only, still the numerical relations 

 are the only basis we have to go by, and are not less reliable than vague 

 statements that there are " many " or " very many " more engaged in 

 this than in that activity. Accordingly, I shall give the numerical 

 results of my observations, which are of necessity the basis of my gen- 

 eral statements of proportions. 



In those cases where two series of observations were made with the 

 food in the same chamber, it was found that there is not much differ- 

 ence in the per cents resulting in the two cases (27.1 and 33.8 ; 25.4 

 and 25.7 ; 6.7 and 6.5 ; 3.2 and 8.9). In experiments with colonies 

 4, 17, 24, 42, and 54 there was a much larger number of ants entering 

 B when the food was in B than when it was in A, as we should expect ; 

 but, for some reason which I have been unable to explain, the reverse 

 was true in colonies 51, 52, 53 and 55. However, the average of these 

 per cents was higher when the food was in B (21.2 per cent) than 

 when it was m A (15.6 per cent). This would leave a difference of 5.6 

 per cent, which may be assumed as the per cent which went to B for 

 food alone. It will be noticed that the per cent of ants entering B is 

 fairly low, showing that not every ant went each day to the food cham- 

 ber, and, indeed, some ants did not enter B at all. This is shown 

 by an examination of the details of a series of observations in colony 

 54. The ants whose numbers are not recorded here died before this 

 experiment was performed. Nos. 25, 28, 35, 37, 39, 45, 47 and 48 did 

 not enter chamber B at all, while out of a possible 33 times, No. 30 

 entered B twenty-two times; No. 2, twenty times; Nos. 21 and 22, 

 seventeen times each; Nos. 10 and 12, sixteen times each; Nos. 3 

 and 52, fifteen times each ; No. 9, eleven times ; No. 20, eight times ; 

 No. 44, six times; No. 14, five times; Nos. 8 and 13, three times 

 each; Nos. 11, 17, 19, 31, 34, and 42, twice each ; and Nos. 15, 19, 

 33, 36, and 40, once each. There were, in fact, instances in all the 

 colonies of failure on the part of some individuals to enter the food- 

 chamber. It might be urged that any one individual does not need 

 food every day, and can readily live for some time without it, as has 



