THE DOBSON BECOMES A HELLGRAMITE. 



In the spring or early summer of the third season of its 

 existence the dobson leaves the stream in which heretofore it 

 has developed, crawls up the bank and seeks the shelter of 

 some log or stone lying above the water 

 level. In the soil beneath this it hollows 

 out an oval cell, in which it generally lies 

 a week or more before ' changing to the 

 pupa state. Finally it transforms to the 

 pupa (Fig. 43). 



Fig. 43. — Pupa of Dobson. c l \ o / 



Compared with its previous form, the 

 most notable change that has taken place in the dobson is due 

 to the absence of the threads along the sides of the body and 

 the presence of the wing pads upon its back. In these the 

 enormous wings of the adult insect are to be developed. 



The dobson remains in this pupa state two weeks. Then it 

 changes again and the adult hellgramite appears. This also 

 is a curious-looking creature. It is of a dull gray color. The 

 head is large and furnished with prominent' eyes and long feel- 

 ers or antennce. The legs are long and stout, and the wings of 

 immense size. They are membranous with a network of veins. 

 When at rest they project some distance beyond the end of the 

 body. The males have a pair of very large pincher-like jaws 

 (Fig. 44). 



These adult hellgramites are nocturnal insects. They 

 remain at rest during the day in such shelter as they can 

 find, and fly about at night. Occasionally one will come 

 into a lighted room through an open window. Sometimes 



44 



