Here's what Wikipaedia has to say about a recent visitor to Cumberland's sewage treatment system:


Dragonflies typically eat mosquitoes, and other small insects like flies, bees, ants and butterflies. They are therefore valued as predators, since they help control populations of harmful insects. Dragonflies are usually found around lakes, ponds, streams and wetlands because their larvae, known as "nymphs", are aquatic. Adult dragonflies do not bite or sting humans, though nymphs are capable of delivering a painful bite.