NEUTER INSECTS. 477 



The conclusions, then, reached in this paper are, that in many 

 cases the differences between fertile and infertile insects are due to 

 the quality or quantity, or both, of the food given to the larvae. This 

 conclusion is of worth, since it is supported by Huber, Smith, Wood- 

 bury, and others ; though these naturalists only apply it to the social 

 bees. The suggestion of Professor Wyman, that the difference in de- 

 velopment is due to the difference in the time the eggs are laid after 

 fertilization, seems to be opposed to facts ; especially to the experiment 

 of Kleine, who reared worker-larvae into queens by feeding them on 

 royal food. The other conclusion is, that the neuters represent the 

 type from which the true males and females have diverged ; that in 

 those cases where food is powerless, the neuter retains its immutabil- 

 ity for the reason that its development is arrested at a certain stage ; 

 that is, it does not go beyond the state reached by the typical progeni- 

 tor, while the perfect males and females go beyond this stage, and 

 that the differences between them and the neuters were inaugurated 

 at this time ; that changed conditions have been potent in producing 

 such differences ; that the differences are only inherited at that ad- 

 vanced period of progression in which they were initiated. In other 

 words, to render this conclusion plain to the general reader, we believe 

 that if the neuter- worker of the white ant, for example, were to pro- 

 gress in development, it would turn into the fertile female ; if the 

 neuter soldier of the white ant were to continue on the line of de- 

 velopment, it would become a fertile male. This does not give support 

 to the theory that the worker and soldier are immature male and fe- 

 male ; that they are the perpetual babies, while the perfect insects are 

 adults since we believe that in their way the neuters are as adult as 

 their parents. This proposition may be rendered clearer by a symbol, 

 which may be represented by the letter Y. The stem of this letter 

 will stand for the typical insect represented at the present day by the 

 neuter, and the two arms, respectively, will represent the male and the 

 female, which, after the typical insect reached a stable form, diverged 

 into new routes of progression. 



At some future time we hope to work out this subject more elabo- 

 rately, and, from the observations and facts already collected, it is be- 

 lieved that the theory can be defended if not vindicated. Our present 

 purpose, however, has been accomplished to introduce to the general 

 reader a subject which has perplexed, and still perplexes, our greatest 

 naturalists. 



