90 THE STUDY OF INSECTS. 



Like the adults, the nymphs are strictly carnivorous. 

 They feed on a great variety of insects ; and they also 

 destroy worms, crustaceans, fish-fry, and tadpoles. 



There are two quite distinct types of insects included 

 in this order; these represent two suborders. 



Suborder Anisoptera (An-is-op'te-ra). 



The Dragon-flics. 



The dragon-flies are easily distinguished by the relative 

 size of the two pairs of wings, and by the attitude of the 

 wings when at rest (Fig. 97). The hind wings are larger 



Ftc. 97.— A dragon-fly. 



than the fore wings and are of a somewhat different shape ; 

 the name Anisoptera, from the Greek anisos, unequal, and 

 pteron, wing, refers to this fact. But the most striking 

 characteristic is the fact that the wings are extended 

 horizontally when at rest. 



Darning-needles, devil's-needles, snake-doctors, spin- 

 dles, and dragon-flies are some of the names given to these 

 insects which dart back and forth over streams and wet 

 places, their rapidly moving wings throwing out gleams 

 of metallic color as they go. Still more beautiful are they 

 when at rest, their wings wide-spread above the abdomen, 

 and as rigid and motionless as if made of iridescent glass; 



