DIMORPHISxM AND POLYMORPHISM 377 



complete formation of the sexual organs would be prevented. 

 We know, indeed, that a fertilised egg may develop into a queen 

 or a worker, according to whether the larva arising from it is 

 fed on royal diet or with the less nutritious food supplied to 

 the workers. 



This explanation, however, even if correct as regards the 

 degenerated parts of the workers, does not sufficiently account 

 for the other differences between the two kinds of females. 

 For the workers are not inferior to the queen bee in all respects : 

 on the contrary, the workers sting is straighter, longer, and 

 stronger, and is provided with more teeth, than the queen's ; 

 the wings, moreover, are longer, the tarsal segment of the 

 hind-limb is provided with the well-known brush, and the tibia 

 has a depression known as the pocket, for carrying the masses 

 of pollen which the insect collects. These two characteristic 

 parts are wanting in the queen. Important differences must 

 also exist as regards the minute structure of the brain, for the 

 instincts of the queen are very different from those of the 

 workers. After fertilisation has taken place, the queen lays 

 eggs, but she neither gathers honey from flowers, excretes wax, 

 nor makes the honeycomb. It is therefore incredible that the 

 queen and workers should be formed by the agency of similar 

 determinants. The germ-plasm must contain double-deter- 

 minants for certain parts of the body of the queen and workers 

 respectivelv. But as we have already assumed the existence 

 of double-determinants for the formation of male and female 

 bees, or at any rate for the development of those parts which 

 differ in the two sexes, we can only make the further assumption 

 that t/ie "- female ' halves of the doitble-detenninants may theiu- 

 selves consist of two halves, corresponding to the queen and 

 worker respectively, and that each of these halves must naturally 

 be looked upon as a complete determinant as regards size 

 and structure. It is of no consequence whether they are re- 

 garded as being closely connected together, or as independent 

 structures in close proximity with one another : in either case 

 they must have arisen by the doubling or tripling of a single 

 ancestral determinant. The terms ' double-determinant ^ and 

 ^ half -determinant are simply used for the sake of simplicity. 

 Their relation to one another is similar to that existing between 

 the homologous but heterodynamous determinants of different 

 ids. 



