Big Yellow May

Family: Ephemeridae

Genus: Hexagenia

Life Cycle: incomplete

Three Life Stages: egg, nymph, adult cycle which includes 2 phases: dun and spinner

Emergence: May-August

Burrower Mayfly Group

Nymph

Body Description

Antennae: 2, short

Head: tusks on head: rounded projection at front of head

Eyes: large

Tails: 3

Wings: pads

Gills: use to circulate throughout their burrows

Legs: 6

Body Colors: pale yellow-brown

Mobility: dig U-shaped burrows

Size: 18-35mm

Hook Size: 6-8, 3X Long

Largest Mayfly. They live in streams and lakes where they can have firm bottoms to dig burrows.

Dun

Body Description

Antennae: 2, short

Eyes: 2 large

Tails: 2

Wings: 2 sets, no marks on them but well veined

Legs: 6

Body Colors: top, light tan to bright yellow with distinct dark markings; bottom, unmarked lighter shade of top

Mobility: are not fast emergers

Size: 22-35mm

Hook Size: 6-10

Spinner

After spinners emerge they mate high above the water. This takes place in flight. After this process the male falls spent to the water and the female returns to lay her eggs, and then falls spent to the water. Trout like all stages of the Big Yellow May but the spinner is least important to the angler.