BUCKINGHAM. — DIVISION OF LABOR AMONG ANTS. 493 



much difference in respect to the sort of individuals which participate 

 most in each occupation, for the results in this respect seem to agree 

 fairly well for each species, whether studied in the laboratory or in the 

 field. This statement must, of course, be understood as applying to 

 such colonies only as have attained sufficient size to contain individ- 

 uals of all classes. Furthermore, it was found in both Camponotus and 

 Pheidole that in the small colonies which were used in the laboratory 

 the larger ants did more work than they do in the field. This is prob- 

 ably due to a reversion on their part to queen instincts (p. 464). It 

 was found that in both genera the investigated activities of the classes 

 generally overlap ; that is, the activities are not limited exclusively to 

 one class, but probably all individuals share more or less in all ac- 

 tivities. In general, however, there appears to be in certain activities 

 a preponderance of large ants, and in certain others of small ones. For 

 example, in Camponotus americanus the small individuals seem to be 

 engaged especially in tending the young, the minors and intermediates 

 together in building, the intermediates in foraging, and the majors in 

 fighting. In C. pictus the minors are especially engaged in tending the 

 young ; the intermediates in carrying food, in foraging, and in carrying 

 other ants ; and the minors and intermediates together in regurgitat- 

 ing (probably), in building, and in licking other ants. In Pheidole 

 piUfera there is no intermediate class, but all these duties are per- 

 formed by the small workers. Moreover, when, as occasionally happens, 

 intermediates are found, they more often approximate the size of the 

 small than the large workers, and even the shape of the head is not 

 wholly like that of the soldiers. In Camponotus there is a slightly 

 greater break between the functions of the majors and those of other 

 ants than there is anywhere else in the worker series, though there is less 

 difference in structure between the extremes than there is in Pheidole. 

 Nor is there as much difference in behavior between the majors and 

 minors of Camponotus as between those of Pheidole. It therefore 

 seems as if the two classes of smaller individuals, the minors and inter- 

 mediates, taken together, share in the work which in Pheidole is 

 accomplished by the small ants. Again, the soldiers of Pheidole and 

 the majors of Camponotus both seem to take a more active part in 

 fighting than do the other workers of either genus. In some species of 

 Pheidole, however, according to Wheeler (:02, p. 770), the soldiers 

 are cowardly and not inclined to fight. Furthermore it has been 

 established by Wheeler (1. c.) that in Pheidole the soldiers of some 

 species prepare insect food, or grain, so that it may be carried home or 

 eaten. I, also, have seen some evidence of this. The small workers, 

 as I have shown, also undoubtedly share in this. It is seldom that 



