NEUROPTEKA. 



177 



This species is common throughout the United States. 

 The larvae are called Dobsons by anglers and are used by 

 them for bait, especially for bass. Figure 216 represents a 

 full-grown Dobson, natural size. These larvae live under 

 stones in the beds of streams. They are most abundant where 

 the water flows swiftest. They are carnivorous, feeding 

 upon the nymphs of Stone-flies. May-flies, and other insects. 



Fig. 215. — Corydalis cornuta. 



Fig. 216. — Corydalis cornuta, larva. 



When about two years and eleven months old, the larva leaves 

 the water, and makes a cell under a stone or some other 

 object on or near the bank of the stream. This occurs dur- 

 ing the early part of the summer ; here the larva changes to 

 a pupa. In about a month after the larva leaves the water 

 the adult insect appears. The eggs are then soon laid; 

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