may·fly | \ˈmā-ˌflī \

Definition of mayfly 

: any of an order (Ephemeroptera) of insects with an aquatic nymph and a short-lived, fragile adult lacking mouthparts and having membranous, heavily veined wings and two or three long, threadlike tails

Note: the wings of the mayfly are held vertically above the body when closed.

called also ephemerid

Illustration of mayfly

Illustration of mayfly

Examples of mayfly in a Sentence

Recent Examples on the Web

Adult mayflies live for just a few days, such a short time that evolution didn’t even provide them with a mouth. Heather Radke, Longreads, "A Beginner’s Guide to Fly Fishing With Your Father," 16 June 2018 Hexagenia limbata are a specific breed of mayfly that emerge all at once in early July. Heather Radke, Longreads, "A Beginner’s Guide to Fly Fishing With Your Father," 16 June 2018 The mayflies covered both gas pumps, obscured the overhead lights and buzzed incessantly. Matthew Martinez, star-telegram, "When mayflies swarm: Watch as a massive horde envelops a Louisiana gas station," 30 May 2018 Finally, biology factors in to a mayfly swarm in Louisiana. CNN, "CNN 10 - May 31, 2018," 30 May 2018 These tiny black mayflies with clear wings are like candy to the trout. Lydia Lohrer, Detroit Free Press, "Memorial Day fishing guide: Hot spots in Metro Detroit, around state," 26 May 2018 Look for drift-and-cast fishing with the popular small spinner rigs, also called mayfly rigs or weapon rigs, all tipped with a chunk of nightcrawler, to begin dominating the action., "Fishing Report for May 11: Western Lake Erie walleye fishing drawing crowds," 11 May 2018 The classical pattern was created primarily for mayfly hatches on the Wolf River. Paul A. Smith, Milwaukee Journal Sentinel, "Smith: 13 famous Wisconsin fly patterns take center stage," 21 Apr. 2018 Between the midges and the mayflies, every week there's a new infestation. Grant Segall,, "Indians reliever Andrew Miller loves town, wants to stay: My Cleveland (photos)," 25 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mayfly.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of mayfly

circa 1653, in the meaning defined above

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Time Traveler for mayfly

The first known use of mayfly was circa 1653

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English Language Learners Definition of mayfly

: a small flying insect that lives for only a short time

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Spanish Central: Translation of mayfly

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Comments on mayfly

What made you want to look up mayfly? Please tell us where you read or heard it (including the quote, if possible).


exaggeratedly or childishly emotional

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