The Dobson and its Family 



dangerous, but, fortunately, they do not function as jaws, and 

 are simply used for the purpose of holding the female during 

 marital caresses. 



The female lays her eggs in white, chalky-looking masses 

 about the size of a nickel five-cent piece. These masses are 

 somewhat convex, and contain about three thousand very small 

 eggs set on end. They are deposited on the leaves of trees over- 

 hanging the water, or on rocks, or the piers of bridges or similar 

 places where the larvae can readily drop into the stream or pond. 



1 8. — Corydalis cornuta. (After Riley.) 



Sometimes they are so abundant as to make the rocks look as 

 though someone had splashed whitewash upon them profusely 

 with a brush. 



The young on hatching drop immediately into the water, 

 descend to the bottom, and during the entire larval life, which 

 lasts two years and eleven months, feed upon other aquatic 

 insects, especially the early stages of the May-flies and stone-flies. 

 They hide under stones in swift-running currents, and possess at 

 the anal end of the body two strong tubercles, each provided 

 with two curved claws, with which they hold firmly to one 

 object or another. They breathe through several pairs of tufts of 



214 



