NET-WINGED INSECTS. 



263 



tribe ; for they catch their prey, which consists of Flies, 

 Musquitoes, Butterflies, etc., on the wing. They do this, 

 however, with their claws, and not, like the Swallows, with 

 their mouths. That they may readily see their prey as 

 they fly about so swiftly hi search of it, they have very 

 large, compound eyes, as you see in Fig. 207, one of our 

 common Dragon-flies, or Darning-needles, as they are 

 often called. These formidable-looking insects are en- 

 tirely-harmless, never biting or stinging when we catch 

 them. They are of great service to us in destroying the 

 Musquitoes, of which they devour a great number. Some 

 species are beautifully variegated in color. 



451. The eggs of these insects are deposited on the 

 leaves of aquatic plants. The Iarva3 live wholly in the 

 water. They have some very singular peculiarities. They 

 have a kind of mask with which they can cover up their 

 mandibles and most of the head. But this mask can be 

 unfolded and extended, and, having on its end a pair of 

 claws, it is used as an instrument for seizing their prey, 

 as represented at A in Fig. 208. At B the insect is seen 

 with the mask folded up. You see here, also, water is- 

 suing from the end of the larva's body. It is in this way 

 that it propels itself through the water, just as a rocket 



Fig. 208. 



