PLATE XXIII. 

 Dytiscus dauricus Gebler. 



Fig. I. Dorsal view of larva (X !)• 



2. Under surface of the head (X 6.5)> 



Agabus tristis Aub6 



Fig. 3. Dorsal view of larva (X 7- 75)' 



4. Maxillae and labrum (X 35)' 



5. Mandible (X 35). 



6. Ventral view of pupa (X 7'75)' 



(3S2) 



