The Burrowing Mayfly is one of North America's largest mayflies and produces some of the most spectacular emergences in the insect world — hatches on the Great Lakes and large midwestern rivers can be so dense they show up on weather radar and cause road closures as drifts of insects pile up like snow. Nymphs spend 1–2 years in silt burrows before the mass synchronized emergence.
Best time to see a Burrowing Mayfly
The best time to see a Burrowing Mayfly is May–July, when about 67% of U.S. sightings happen, based on 2,101 research-grade iNaturalist observations.
Not certain it is a Burrowing Mayfly? What bug is this? walks through what to check first and the lookalikes that catch people out.
Recent Burrowing Mayfly sightings near you
Live, research-grade observations from iNaturalist. Allow location to center the map on you.
Spotted a Burrowing Mayfly?
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