PLATE D. 



Dytiscus marginalis digging itself in for pupation. 

 1 to 6. Successive stages of operations. 

 All slightly less tlian i> natural size. 



PLATE E, 



Dytiscus marginalis. Pupation. 



1. Exterior of pupation chamber. 



2. Showing opening made by imago for exit. 



3. Pupa shortly after emergence. 



4. Pupa in normal resting position, lateral view. 



5. ,, „ ,, anterior view. 



6. „ „ ,, posterior view. 



All slightly less than h natural size. 



PLATE F. 



Dytiscus marginalis. 



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 larvs 



preparing for pupation, etc. 



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



