Mayflies

Mayflies, or shadflies, are aquatic insects in the order Ephemeroptera. There are several thousand species of mayflies, distributed among 20 families. Mayflies have a relatively protracted nymphal stage, which occurs in freshwater habitats. The adults are a short-lived stage during which dense aggregations of animals engage in a frenzied procreation, needed to perennate the species in its local habitats.