The Brushlegged Mayfly (Ephemeroptera) is in Old Quebec City, Quebec, Canada, on June 26, 2025. Mayflies are unique among insects in that they moult one more time after acquiring functional wings; this is also known as the alate stage. This last-but-one winged instar usually lives a very short time, often a matter of hours, and is known as a subimago or, to fly fishermen, as a dun. Mayflies in this stage are a favorite food of many fish, and many fishing flies are modeled to resemble them. The adult mayflies are short-lived, from a few minutes to a few days depending on the species. About 2,500 species of mayflies are known worldwide, including about 630 species in North America. (Photo by Creative Touch Imaging Ltd./NurPhoto via Getty Images)
