LIFE HISTORY OF CARPENTER ANT. 1 93 



nation of this is not easy, yet I presume that I shall do no vio- 

 lence if I attempt one. 



The most obvious external condition which may be responsible 

 for this phenomenon is the food supply of the colony. During 

 the first years the workers are few and the domestic duties are 

 proportionally large. The permanent home must be established 

 and there is consequently comparatively little time for food 

 gathering, and probably in many cases relations are not readily 

 established with a suitable herd of aphids, so that in all proba- 

 bility the larvae of these years are scantily fed or are fed a less 

 varied and less concentrated food than that given those that 

 appear when the colony is more mature. During the later years 

 the formicary is well established and there are larger and more 

 powerful workers to make what extensions are necessary. The 

 working force is increased proportionally more than the number of 

 larvae to be fed. These workers range over a wider field and collect 

 not only more, but a greater variety of food. There can thus be 

 little question that the larvae of the large colony are better fed 

 than are those of the small one, and since the better feeding is 

 parallel with the production of more perfect forms, it seems only 

 reasonable to believe that there is some relation between them. 

 If it be asked, why do not all the workers of a given season de- 

 velop into the same size or form, I think that I can say in reply 

 that the food is not equally distributed. I have had numerous 

 instances of a few of the larvae developing much more rapidly 

 than others in my artificial nests. The winter larvae when taken 

 were all practically of the same size, and many of them remained 

 unchanged in size for several weeks after being brought into the 

 insectory, while others, usually a small portion of the whole num- 

 ber, soon began to grow quite rapidly. 



This leads us to the conclusion that the variations in form are 

 ontogenetic in origin, that the fertilized eggs of the queen are all 

 essentially alike when laid, and each capable of developing into a 

 small worker or a winged queen. This conclusion is supported 

 by a view proposed by Emery in a paper entitled " Die Ent- 

 stehung und Ausbildung des Arbeiterstandes bei den Ameisen." 

 I quote the following sentences of this paper from Wheeler's 

 " Polymorphism of Ants " [Bulletin of American Museum of 

 Natural History, Vol. XXIII., Article I.) : 



