mayfly

From May +‎ fly.

mayfly (plural mayflies)

1. Any of the many fragile insects of the order Ephemeroptera, that develop in fresh water and live very briefly as winged adults.
   • 2002, John Gooderham, Edward Tsyrlin, The Waterbug Book, page 132,

     Adult mayflies have large compound eyes and most have two pairs of wings. […] Mayfly nymphs are distinguished by their three tails (two cerci and a terminal filament) and the set of gills on each side of their abdomen.

   • 2005, Terry Hellekson, Fish Flies: The Encyclopedia of the Fly Tier's Art, page 213,

     Mayflies are fragile, gossamer-winged insects that arise from bodies of water and often swarm in great numbers.

   • 2010, Barbara L. Peckarsky, J. David Allan, Angus R. McIntosh, Brad W. Taylor, Chapter 9: Understanding the Role of Predation in Open Systems, Ian Billick, Mary V. Price (editors), The Ecology of Place, page 195,

     Stoneflies have negligible consumptive (thin solid line) and behavioral effects (thin dashed line) on mayfly abundance. Consumption by trout decreases the abundance of mayflies (solid line), but trout suppress mayfly emigration (drift) and thereby increase their abundance (thick dashed line).

In some English dialects, the alternative plural form is "mayfly". For exampleː While some animals take months to reproduce, mayfly need just one perfect day.

• (any species of Ephemeroptera): shadfly

• hatch