PLATE T>. 



Dytiscus marginalis digging itself in for pupatictn. 

 1 to 6. Successive stages of operations. 

 All slitrlitlv less than J naturol size. 



PLATE E. 



Dytiscus marginalis. Pupation. 



L Exterior of pupation chamber. 



2. Showing opening made by imago for exit. 



3. Pupa shortly after emergence. 



4. Pu])a in normal resting position, lateral view. 



5. ,, „ ,, anterior view. 



6. ,, ,, ,, iJosterior view. 



All slightlv less than i natural size. 



PLATE F. 



Dytiscn s m argina lis. 



1. Male, just emerged from pupal skin. 



2. Male, 24 hours later. 



3. Female, just emerged from pupal skin. 



4. Female, 24 hours later. 



5. Artificial pond and bank for the observation of the larva 



preparing for pupation, etc. 



1 to 4, slightly less than h natural size; 5, about J natural size. 



