194 JOHN L. PRICER. 



" The peculiarities in which the workers differ from the corre- 

 sponding sexual forms are, therefore, not innate or blastogenic, 

 but acquired, that is somatogenic. Nor are they transmitted as 

 such, but in the form of a peculiarity of the germ plasm, that 

 enables this substance to take different developmental paths 

 during ontogeny." 



Wheeler remarks in connection with this quotation that the 

 view presented has never received the attention that it merits, 

 and I trust that the data that I have brought out in connection 

 with the life-history of a colony may serve to strengthen it ap- 

 preciably. Wheeler has also elsewhere (" A Neglected Factor 

 in Evolution," Science, N. S., Vol. XV., pp. 766-774) referred to 

 the influence of the age and trophic status of the colony on the 

 variability of the polymorphic ants. 



Division of Labor. 

 Division of labor among the workers, like their polymorphism, 

 is incomplete ; and yet, in the one outdoor colony which I studied, 

 very marked traces of it were seen. This colony, which I shall 

 designate as colony A, lived in a large maple tree which stood 

 on the border of a city block containing but three houses, the 

 rest of the block being vacant, and allowed to grow up in weeds. 

 One hundred and fifty feet away from the nest tree of this colony 

 and just at the rear of one of the houses, stood a cotton wood tree, 

 five or six years old ; and near this was a clump of small boxelder 

 trees. The cottonwood was infested with one species of aphis 

 and the boxelders with another. The ants adopted these two 

 "herds" of aphids as their main source of food, but showed a 

 decided preference for those on the cottonwood. At the base of 

 this tree they constructed a temporary chamber, by entering into 

 a crack in the ground and carrying out the particles of earth as 

 they do the particles of wood from their permanent home. After 

 they had used this retreat for a time, I tore it open and, by means 

 of glass plates, constructed a chamber for them somewhat like a 

 Fielde nest, covering it with a piece of orange-colored glass 

 through which I could easily observe what occurred beneath. 

 This the ants readily accepted as equivalent to the one that they 

 had constructed, and used it throughout the summer. 



