112 The Under-Water World 



often seen hawking swiftly over some 

 pond or length of stream, and the other 

 kind belonging to the much smaller and 

 comparatively feebly flying type known 

 as the "demoiselle." Both kinds are 

 carnivorous, the large one particularly 

 so. Certain of the mouth-parts are fused 

 to form a prehensile organ capable of 

 being shot rapidly forward in order to 

 seize the prey ; this apparatus is known 

 as the " mask," as when not in use it 

 conceals the other mouth-parts. Small 

 fish, other insect larvae, tadpoles, etc., all 

 are prey to these fierce larvae. Some 

 species crawl about on the muddy bottom 

 of ponds or climb among the weeds. 

 When the full larval size is reached and 

 the adult insect is ready for emergence 

 the larva climbs up a reed stem until 

 above the water level, and there rests until 

 the skin is dry ; a fissure then appears 

 along the back, and through the opening 

 the perfect insect makes its way. The 



