Influence of the Primary Reproductive Organs. 605 



gland). There was no case of the absence or modification of the 

 secondary sexual characters in any of these eighteen moths. All 

 males had both antennae of the usual male type although the 

 testis of one side or the other was wholly wanting, or even both 

 were absent. 



The experiments prove that for Bombyx mori (a) there is no 

 regeneration of mutilated or destroyed developing reproductive 

 glands even though the glands be destroyed or mutilated as early 

 as just after the second larval moulting, and (b) that the destruc- 

 tion of the primary reproductive organs (ovaries or testes) before 

 the secondary sexual characters are developed has no effect on 

 the normal course of development of these characteristics. 



