Source : WordNet®

ephemerae
     See {ephemera}

ephemera
     See {ephemeron}
     [also: {ephemerae} (pl)]

ephemera
     n 1: something transitory; lasting a day
     2: an insect that lives only for a day in its winged form [syn:
         {ephemeron}]
     [also: {ephemerae} (pl)]