Explanation of Plate C. 



To illustrate colour differences in pupae of P. brassicae exposed to 

 different temperatures at period of pupation (see Proceedings, p. Iviii). 

 All the P. brassicae were affected like those photographed. Pupae 

 of P. rapae treated in the same way showed similar effects, but with 

 decided exceptions. 



3 upper figures at normal temperature. 

 3 lower figures at 86°. 



Twice natural size. 



