76 



THE STUDY OF INSECTS 



molt these grow larger, until finally the last skin of the water-nymph is shed, 

 and gills and mouth-parts arc all left behind, and the insect comes forth, a 

 winged mayfly. But there is still another change to be undergone. The 

 insect has not yet reached the adult state. After flying a short distance it 

 alights and sheds its skin again, a thin layer coming off from all parts of its 

 body, even from its wings. After this the delicate creature is more fragile 

 than before. It now has but one duty to perform in its brief life in the air, 

 and that is to lay its eggs. These are sometimes laid on the surface of the 

 water, and sometimes the mother wraps her wings about her like a diving- 

 bell and goes down into the water and deposits her eggs on stones and then 

 dies. 



This excellent illustration after Needham, shows a characteristic may- 

 fly (A), with its long front legs, triangular wings, and slender caudal 

 setae. It has transformed from the nymph (B), which spent its long life 

 in the water where it obtained air by means of the feathery gills along 

 the sides of the abdomen. 



