Metamorphosis 



645 



Fig. 226. Above, A chain of six brainless diapausing pupae had been established in parabiosis and 

 a single chilled pupal brain implanted under the facial window of the anterior-most individual. 

 When pupae 1 and 2 showed the initiation of development, about 17 days later, pupae i and 6 were 

 detached as seen above. Below, The same preparation seven weeks later. After detachment of the brain- 

 containing pupa, the activation has continued to spread down the chain of interconnected pupae. The 

 isolated pupa, however, failed to develop. (After Williams, '52.) 



