'Tis the season for Mayflies (Fishflies) to give us something to watch on radar each night as they hatch. #miwx pic.twitter.com/9QxPss2w0g
— NWS Detroit (@NWSDetroit) June 19, 2016
When mayflies “hatch”—that is to say, moult into their final, adult “imago” form—they emerge in truly enormous numbers. Numerous enough to turn up on the National Weather Service’s radar earlier this month. [CBC News]