From Longman Dictionary of Contemporary Englishmayflymay‧fly /ˈmeɪflaɪ/ noun (plural mayflies) [countable] HBIa small insect that lives near water, and only lives for a short time
Examples from the Corpus
mayfly• The other main type of life-cycle is followed by insects such as the aphids, grasshoppers, dragonflies and mayflies.• In lakes, crustaceans, molluscs, leeches and mayflies dwindle, although predators remain more numerous, feeding on alternative prey.• There were squirming, naked mayfly nymphs that had always been hidden before.• The nymphs, or first larval stages of mayflies, are also adapted to very particular conditions.• This is the day in the life of the mayfly.• Yet the return of the mayflies is no longer as inevitable as the return of May.• The loch has some splendid fish and, in late June and early July, a wonderful mayfly hatch.Origin mayfly (1600-1700) May + fly; because it was believed it only lived in May 