288 Fresh Water Aquarium 



ply of air. This it accomplishes by turning 

 the rear end of the abdominal part of the 

 body upward, lifting" it somewhat out of the 

 water, and, at the same time slightly open- 

 ing the wing covers for a moment. In the 

 evening the beetles leave the water and can 

 frequently be seen around electric lights. 

 After dropping to the ground, if the surface 

 is smooth, they have great difficulty in rising 

 again, and they can then easily be collected in 

 large numbers. The object of their flight 

 abroad is either to hunt for prey or to mate. 

 Often they will be found in puddles of rain 

 water, in barrels or other vessels filled with 

 water and remote from any pond or river. 

 To prevent their escape, the vessel, in which 

 they are kept in confinement, should be cov- 

 ered with a fine wire netting. 



The Yellow-bordered Water Beetles are 

 by far the most fearless, aggressive and 

 cruel robbers of the many which make life 

 miserable for the fishes, amphibians and 

 even the larvae populating our waters. 



