Dayfly /(dā"flī`)/

Day·fly

Dayfly

n.
  1. 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. (Zool.) [Outdated]