370 ANTS. 



develop into repletes. In the nests which I excavated during July 

 there were many callow workers, males and females. While keeping 

 several colonies in artificial nests it occurred to me that the change from 

 the ordinary to the replete worker must begin during the callow stage, 

 while the integument of the gaster is still very soft and distensible. I 

 accordingly isolated a number of young callows in two of my nests and 

 fed them with maple syrup and cane sugar water. They partook of 

 these substances greedily, and a few of the workers in each nest grad- 

 ually began to assume the replete condition. During the course of four 

 to six weeks several of them became what I have called semirepletes 

 (McCook's semirotunds), and four, three in one nest and one in the 

 other, actually attained the dimensions of the perfect replete. Most of 

 the workers, however, showed no inclination to assume this form. In 

 most cases, as Me Cook has shown, it is the major workers which most 

 readily become repletes, but this is not an invariable rule. In the 

 honey chambers of opulent colonies I have usually found also a few 

 replete mediae and minima? hanging among their larger but no more 

 turgid sisters. Thoroughly hardened workers of the ordinary form, 

 according to my observations, are no longer able to become repletes. 

 It is probable that McCook's failure to secure these from isolated major 

 workers was due to his using old individuals in his experiment. 



Why certain callows should aspire to become animated pots or tuns,, 

 while others prefer to be active foragers and providers, is an enigma. 

 I do not believe, however, that this is due to differences in the " struc- 

 ture or form of the intestine and abdominal walls," as McCook sug- 

 gests. It is more probably an unusual example of the division of labor, 

 which is shown by careful study to exist in various forms and degrees 

 among all ants with monomorphic workers. The individual worker 

 performs different duties at different stages in its life, beginning in its 

 callow stage as a mere nurse, then becoming a forager, warrior or 

 guard, and in its old age sometimes encroaching on the function of the 

 queen and becoming a parthenogenetic mother, or gynaecoid. It is not 

 improbable that many worker ants acquire habits using this word, for 

 the moment, in its restricted and technical sense as employed in human 

 psychology and tend to perform throughout life the particular func- 

 tion which they happen to assume while in the callow stage. This may 

 account for the development of the passive replete, not only in M. Jiortt- 

 deonun, but also in all other honey ants. Those who, in anthropo- 

 morphic mood, are wont to extoll the fervid industry and extraordinary 

 feats of muscular endurance in ants, should not overlook the beatific 

 patience and self-sacrifice displayed by the replete Mynnccocystns as 



