POLYMORPHISM. i*9 



mount to the assumption that the phylogenetic differentiation of the 

 castes arose in the sphere of function before it manifested itself in 

 structural peculiarities. Although this view implies that the female, or 

 (jueen was the source from which the instincts and structures of the 

 worker were derived, it has been obscured by an improper emphasis 

 on the instincts of the honey-bee, in which the female is clearly a degen- 

 erate organism, and on certain specialized instincts, supposed to belong 

 exclusively to worker ants like those of the slave-makers (Polyergus 

 and Formica sangiiinca). We have therefore to consider first the in- 

 stincts of the queen, and second, any evidence that may go to show that 

 instinct-changes precede morphological differentiation in the phylogeny 

 of the species. 



It is evident that the social insects may be divided into two groups 

 according to the instinct role of the queen. In one group, embracing 

 the social wasps, bumble-bees, ants and termites, the female is the 

 complete prototype of her sex. Even the queen of the slave-making 

 ants, manifests in the founding of her colonies all the threptic instincts 

 once supposed to be the exclusive prerogative of the worker caste. 

 These may be called the primary instincts. After the colony is estab- 

 lished, however, and she no longer needs to manifest these instincts, 

 she becomes a mere egg-laying machine and her instincts undergo a 

 corresponding change and may now be designated as secondary. She 

 thus passes through a gamut of instincts successively called into activity 

 by a series of stimuli which in turn arise in a definite order from her 

 changing social environment. The workers, however, are capable of 

 repeating only a portion of the female gamut, the primary series. In 

 gynscoid individuals there is also a tendency to take up the secondary 

 series, but in most workers this has been suppressed by countless 

 generations of nutricial castration. The social insects of this type may 

 be called gyncccotclic, to indicate that the female preserves intact 

 the full series of sexual attributes inherited from her solitary ancestors. 

 In these the primary and secondary series are simultaneous or overlap 

 completely, in the gynsecotelic social insects they are extended over a 

 longer period of time and overlap only in part, as social life permits 

 the extension of the secondary long after the primary series has lapsed 

 into desuetude. It will be seen that the division of labor which led 

 to the special differentiation of like females into workers and queens 

 is clearly foreshadowed in the consecutive differentiation of instincts 

 in the individual queen. The second group of social insects is repre- 

 sented by the honey-bees and probably also by the stingless bees (Meli- 

 poniclae). In these only the secondary instincts are manifested in the 

 queen, while the worker retains the primary series in full vigor and 



