THEIB LIFE HISTORY. 



299 



you will find that whenever the insect glides along in 

 this mysterious manner, the sand is scooped away so as 

 to form a shallow groove. 



This is caused by the singular mode of propulsion 

 employed by the dragon-fly while still in the larval state. 



DRAGON-FLY LARVA TAKING ITS PREY. 



If you look at the tail of the insect, you will see that 

 there are three radiating spikes. These surround the 

 entrance to a tube which traverses nearly the whole body 

 of the insect. By a peculiar structure, water can be 



