METAMORPHOSIS OF THE DRAGON FLY. 



Ill 



The pupa scarcely differs from the larva, except in having 

 larger wing-pads (Fig. 132). It is still active, and as much of 

 a gourmand as ever. When the insect is about to assume the 

 pupa state, it moults its skin. The body having outgrown the 

 larva skin, by a strong muscular effort a rent opens along the back 

 of the thorax, and the insect having fas- 

 tened its claws into some object at the 

 bottom of the pool, the pupa gradually 

 works its way out of the larva-skin.' It 

 is now considerably larger than before. 

 Immediately after this tedious operation, 

 its body is soft, but the crust soon hard- 

 ens. This change, with most species, 

 probably occurs early in summer. 



When about to change into the adult 

 fly, the pupa climbs up some plant near 

 the surface of the water. Again its back 

 yawns wide open, and from the rent our 

 Dragon fly slowly emerges. For an hour 

 or more, it remains torpid and listless, 

 with its flabby, soft wings remaining 

 motionless. The fluids leave the sur- 

 face, the crust hardens and dries, rich m Pupa of ^ 8Chn a. 

 and varied tints appear, and our Dragon fly rises into its new 

 world of light and sunshine a gorgeous, but repulsive being. 

 Tennyson thus describes these changes in "The Two Voices" : 



To-day I saw the Dragon fly 



Come from the wells where he did lie. 



An inner impulse rent the veil 



Of his old husk : from head to tail 



Came out clear plates of sapphire mail. 



He dried his wings; like gauze they grew; 

 Through crofts and pastures wet with dew 

 A living flash of light he flew. 



Of our more common, typical forms of Dragon flies, we figure 

 a few, commonly observed during the summer. The three- 

 spotted Dragon fly (Libellula trimaculata), of which figure 133 

 represents the male, is so called from the three dark clouds on 

 the wings of the female. But the opposite sex differs in having 

 a dark patch at the front edge of the wings, and a single broad 

 cloud just beyond the middle of the wing. 



Libellula 'quadrimaculata, the four-spotted Dragon fly (Fig. 



