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Family Cordulegasteridae

This group is also considered by recent authors to be simply a subfamily of the Aeschnidae. 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 comparatively 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 imagos 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.