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University of Minnesota Extension

Extension > Garden > Diagnose a problem > What insect is this? > General/curiosity insects > Insects with obvious wings: less than ¾ inch long > Mayflies

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Ephemeroptera order


Whitney Cranshaw, Colorado State University,


Jeff Hahn, University of Minnesota Extension

Description: 1/4 - 1 1/4 inch long. Soft-bodied insects with clear, triangular-shaped wings; slender abdomen with 2-3 long filaments (cerci) at the end of it.

Where/When: Associated with water and nearby areas, attracted to lights and can be found around buildings, often in large numbers; present May into September.

Significance: They can be a nuisance when they occur in large numbers. They do not harm people or property.

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