Hydrophilidoe 209 



wing covers make a straight line where they join 

 on the back, rest in the water head downward, with 

 the tip of the tail at the surface. Many of the 

 insects carry the air down with them, covering the 

 whole under side of their bellies with minute 

 ])ubbles, which gives them the appearance of being 

 coated with quicksilver. When frightened, the 

 whirligigs hitch a bubble of air to the hind tip of 

 their body, and dive below with this supply of 

 breathing material. They remain under the water 

 clinging to a stone, stick or plant until more air is 

 needed, then come to the surface and renew the 

 supply. 



Some water beetles deposit their eggs upon the 

 under side of a leaf (Fig. 181 ) or floating stick and 

 supply the eggs (and the young when hatched) 

 with air by enclosing the eggs in a waterproof sack 

 or bag in one end of which they attach a horny 

 pipe or tube extending up to the air. 



HYDROPHILIDiE 



You can remember that name by thinking of 

 hydrophobia, hydroplanes and hydrants. The 

 Triangular (Fig. 182) is one and five-tenths inches 

 long and shiny black. ]Most of the water beetles' 



14 



