PLATE III. 
1. Dytiscus punctulatus (male). 
2. Agabus maculatus. 
3. Hydroporus rivalis. 
4. Haliplus obliquus. 
5. Pelobius Hermanni. 
6. Gyrinus bicolor. 
6 a. Head of ditto, seen later \ 
6 b. Antenna of ditto. 
6 c. Hind leg of ditto. 
