This genus of dragon flies is one of the groups whose members are accounted rare in collections, though quite abundant in nature. With the exception of three species, two of which have only been obtained in numbers by breeding, few imagoes have been taken. Although I have collected carefully for several years in localities where a few species were common enough, I have seen but three imagoes at large, but I have bred one species by hundreds, and have seen the exuviæ upon the banks of streams by tens of thousands.

Nymphs of this genus seem to prefer the sandy or gravelly beds of clear, rapid streams, flowing through rocky woods. What becomes of the countless imagoes which issue from such places by night in early summer I have not as yet been able to find out.