230 
ANIMAL CURIOSITIES 
may deposit their eggs in the buried carcase, 
the ova being hidden from the eyes of prying 
enemies, and the young being assured of a 
supply of food when they hatch out. 
Another beetle (Dytiscus marginalis) is an 
expert diver. It is found chiefly in stagnant 
waters, and swims with the aid of its strong 
hind legs which act as a pair of oars. Like 
other living creatures it requires a supply of 
air in order that it may breathe, and as it is 
unable to extract the oxygen held in the water 
in the manner that fish do through the agency 
of gills, it overcomes the difficulty by taking 
down a supply of air with it, making periodic 
journeys to the surface of the water for this 
purpose, and thrusting its tail into the atmo¬ 
sphere. The air then enters the beetle’s spiracles 
or breathing holes, from whence it is conducted 
all over the body through a number of small 
tubes, while a further supply is also carried 
between the closely-fitting wing-covers and the 
back of the body. 
A diving-beetle has been known to remain 
under-water for nearly twenty minutes on end, 
but as a rule they come to the surface for a 
fresh supply of air at intervals of about eight 
or nine minutes. They are strong flyers, an 
accomplishment that is necessary to enable 
them to reach a new habitation should the 
