AQUATIC BEETLES 



91 



bottom with a large bubble attached to its tail, which 

 clings to it with great tenacity and raises it above the 



ground. 



While hanging from the surface the larva 



Fig. 20. — Larva of Hydrobius fuscipes (magnified) ; head of do., under side ; tail- 

 end, showing respiratory cup and trachese. 



executes a great variety of movements, bending its 

 body upwards, downwards, or sideways in search of 

 its prey. If kept in deep water for a long time it 

 drowns. 



