FAMILY CORDULEGASTERID^E 



This group is also considered by recent authors to be simply 

 a subfamily of the ^Eschnidae. They resemble the species of the 

 foregoing group, but the eyes touch at a single point on the top 

 of the head. They are all large insects, and there are compara- 

 tively few of them in the United States. None of them are 

 common. The colors are not metallic, but their bodies are 

 usually banded with brown and yellow, the wings for the most 

 part being nearly clear. 



Needham says: "The images are strong of flight, and are 

 oftenest seen coursing back and forth over some small stream, 

 flying on a regular beat, and passing and repassing the same 

 point at intervals of a few minutes. The collector may take 

 advantage of this habit and so station himself that he may reach 

 the specimen as it passes and capture it if dexterous enough with 

 the net. The nymphs live on the bottom in shallow water, 

 buried in clean sand or in vegetable silt. Though buried, they 

 do not burrow, but descend by raking the sand from beneath 

 them by sweeping lateral movements of the legs. When deep 

 enough, they kick the sand up over the back till only the elevated 

 tips of the eyes and the respiratory aperture at the tip of the 

 abdomen are exposed. By placing a live nymph in a dish of 

 sand and water, and watching, its method may be observed in a 

 very few minutes. The whole comical performance reminds one 

 strongly of the descent of an old hen in a dust bath." The same 

 authority says that, when once placed, the nymph will remain 

 for weeks without changing position, but when some little insect 

 comes near it throws out its jaws and captures it. One species 

 was seen in the nymph stage to capture and eat young brook 

 trout as long as the nymphs themselves. 



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