Dayfly

A neuropterous insect of the genus Ephemera and related genera, of many species, and inhabiting fresh water in the larval state; the ephemeral fly; -- so called because it commonly lives but one day in the winged or adult state. See Ephemeral fly, under Ephemeral.

slender insect with delicate membranous wings having an aquatic larval stage and terrestrial adult stage usually lasting less than two days