ODONATA. 211 



adults; May-fly nymphs, some weaker nymphs of their 

 own kind, and aquatic worms. 



Some dragon-fly species do not attain their full size 

 under a year, while others reach adult size in a few months. 

 ■The nymph comes to maturity by frequent moultings; 

 the exact number of moults is not known, but an old 

 nymph may be known by its size and dingy color. Just 

 before each moult, the colors are uniformly dingy brown, 

 while the new nymph will be a brighter color, usually 

 greenish; and- when it approaches maturity it will 

 approximate the size of the adult dragon fly. 



If you are fortunate enough to live near a pond, go 

 down to it some warm spring morning or morning in the 

 early summer, and you may be lucky enough to see some 

 dragon fly making its final moult. Here it comes, a 

 clumsy,^ big-headed thing, dragging itself up out of the 

 water on to a grass stem or on to the mud at the water's 

 edge. It sits still in the sunshine while its old nymphal 

 skin dries and cracks along the back, and out of the rent 

 there begins to appear the adult insect, shoulders first, 

 and head afterward. After considerable maneuvering 

 it is finally free, and you see a wet-skinned, soft-bodied 

 dragon fly, with its big wings wet and wrinkly and yet 

 lacking the brilliant colors. It may take. a good share of 

 the forenoon to dry. Drying means the hardening of the 

 chitin in its body wall; and in its wings the chitin ribs 

 must dry before the insect can perform its wonderful 

 feats of flight. The colors gradually come out as the 

 body dries, and possibly while you are looking, the shining 

 wings expand and off sails the insect on its maiden flight, 

 for its first breakfast on land. 



The old nymphal cases, or exuviae, may be found 

 around the water's edge, or you may rake them out as you 



