INSECTA 



71 



in through the anus and then squirting the body forward. 

 The adult dragon-flies rest with their wings stretched out 

 on either side of the body. They are expert flyers and are 

 of benefit to man on account of the great numbers of mos- 

 quitoes they destroy. A dragon-fly catches all its prey 

 on the wing. Its enormous eyes cover the whole of the 



FIG. 39. Termite nests. At the right is a section of a tree and a carton nest; 

 at the left a mound nest is shown. 



head (30,000 facets are present in one species); its long 

 light wings enable it to fly with great swiftness in any direc- 

 tion. The larvsB of all Odonata have a peculiar grasping 

 pair of mandibles, which can be greatly extended to capture 

 food, or folded up like a hinge beneath the head when not 

 in use. 



Order 4. Plecoptera (Fig. 38). The stone-flies are 

 heterometabolous, aquatic insects, with biting mouth parts. 



