Genus Hexagenia

Burrowing Mayfly, Giant Mayfly, Golden Mayfly

Author of genus is Walsh 1863

5 spp. in our area(1)

14-30 mm

Very large mayflies. Usually pale golden yellow at least when freshly emerged, i.e., subimago. Several species dark with bold striped pattern as mature imagos. Wings not uniformly dark, as are some other genera of this family. Pale brown band across abdomen. Antennae, legs, and tails yellow. (Photographs show either pale golden mayflies--probably subimagos, or very dark individuals, full imagoes?) H. limbata is very large (18-30 mm), widespread in east. H. bilineata is smaller, 14-18 mm, and is common in southeast.

Naiads have three anal filaments.

all spp. occur in the east, H. limbata throughout NA, H. bilineata ranges to sw. US(1)

streams, lakes

Summer. May-September

Eggs are dropped onto water surface, sink to bottom. Larvae (naiads) burrow in muddy bottoms of streams, lakes at up to 20 meters (60 feet) in depth. They usually spend one year in this stage, perhaps two in northern areas. Adults emerge in evening, disperse widely, coming to lights--often far from bodies of water.