NUCLEAR SIZE OP NERVE CELLS 75 



in nuclear size in old adults is due to fatigue or old age or both, 

 how are we to explain the larval and pupal change? The larvae 

 of the bee are inactive so that they are more like the pupa than 

 is usual in insects. Metabolism is very active during the larval 

 period but this can hardly result in fatigue to nuclei in the brain. 

 One would expect that the changes that take place during the 

 metamorphosis in the pupa would drain heavily on the energy 

 of the insect, and yet the same rhythmic nuclear changes in size 

 continue through this period. So far as activity is concerned 

 these stages give us the two extremes, the larvae and pupae 

 at rest, the adults of summer extremely busy and the win- 

 ter workers relatively inactive. If there is a definite nuclear 

 change with work, the stages selected should give us some in- 

 dication of it. In place of definite nuclear change with age, we 

 find a constant variation which tends to be rhythmic. 



CONCLUSIONS 



1. In the honey bee worker there is a definite variation in the 

 nuclear size of the nerve cells studied. 



2. Changes in nuclear size dependent on the life cycle are un- 

 Uke in cells of different type. 



3. The changes in nuclear size can not be explained as due to 

 the effect of old age or fatigue. 



