AQUATIC BEETLES 



89 



Mr. W. F. Baker : " Hydrobius is a vegetarian, and 

 may be found in any weed-grown pond, being gener- 

 ally accompanied by another Beetle of like habits, 

 Helophorus aquaticus. One or both of these is 

 pretty sure to be found at the right season in any 

 shallow pond covered with a carpet of Duckweed. 

 In such a pond there will be few or none of the Dytis- 



FIG. 19. Hydrobius fuscipes. X 8. 



cidae (Acilius, Agabus, Dytiscus, &c.), which prey 

 upon small Beetles, for the mode of respiration of the 

 Dytiscidae requires open spaces, where they may 

 come to the surface and breathe without obstruction. 

 Any circumstance which discourages these carnivorous 

 Beetles favours the increase of Hydrobius and Helo- 

 phorus." 



