88 THE STUD V OF INSECTS, 



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. The life of the 

 nymph is from one to three years, according to the species. 



