50 Annals Entomological Society of America [Vol.1, 



centrating his attention on the reactions of the animal to the stim- 

 uli proceeding from its environment, is inclined to study its later 

 stages as determined by the reactions to such stimuli, without 

 regard to any internal or hereditary predetermination or disposi- 

 tion, while the embryologist seeks out the earliest moment at 

 which the organism may be shown to deviate from the ontogenetic 

 pattern of its parent. If this moment can be detected very early 

 in the development he will be inclined to project the morphologi- 

 cal differentiation back into the germ-plasm and to regard the 

 efforts of the physiologist as relatively unimportant if not alto- 

 gether futile. Now in his study of the social insects the embryol- 

 ogist is at a serious disadvantage, since he is unable to distinguish 

 any prospective worker or queen characters in the eggs or even 

 in the young larvae. Compelled, therefore, to restrict his inves- 

 tigations to the older larvae, whose development as mere processes 

 of histogenesis and metamorphosis throws little or no light on the 

 meaning of polymorphism, he is bound to abdicate and leave the 

 physiologist in possession of the problem. 



The physiologist in seeking to determine whether there is in 

 the environment of the developing social Hymenopteron any 

 normal stimulus that may account for the deviation towards the 

 worker or queen type, can hardly overlook one of the most impor- 

 tant of all stimuli, the food of the larva. At first sight this bids 

 fair greatly to simplify the problem of polymorphism, for the 

 mere size of the adult insect would seem to be attributable to the 

 quantity, its morphological deviations to the quality of the food 

 administered to it during its larval life. Closer examination of 

 the subject, however, shows that larval alimentation among such 

 highly specialized animals as the social insects, and especially 

 in the honey-bees and ants, where the differences between 

 the queens and workers are most salient, is a subject of con- 

 siderable complexity. In the first place, it is evident that 

 it is not the food administered that acts as a stimulus but the por- 

 tion of it that is assimilated by the living tissues of the larva. 

 In other words, the larva is not altogether a passive organism, 

 compelled to utilize all the food that is forced upon it, but an 

 active agent, at least to a certain extent, in determining its own 

 development. And the physiologist might have difficulty in 

 meeting the assertion that the larva utilizes only those portions 

 of the proffered food which are most conducive to the specific 

 predetermined trend of its development. In the second place, 



