Giant Salmonfly (Stonefly)

Order: Plecoptera

Family: Pteronarcidae

Genus: Pteronarcys

Life Cycle: incomplete

Three Life Stages: egg, nymph and adult

Emergence: April-July

Nymph

Body Description

Antennae: 2 long

Eyes: 2 fair sized

Tails: 2

Wings: pads on top of thorax

Gills: tufts are under the front part of the body or may be absent

Abdomen: 10 segments-evenly cylindrical

Legs: 6 with sharp claws on each

Mobility: poor swimmers

Body Colors: dark brown to black

Size: 1 ½” or more, 25-50 mm

Hook Size: 4-8, 3X long

Nymphs take anywhere from 2-4 years to emerge depending on the temperature and abundance of food. They cling to the undersides of rocks where they feed on plant debris.

Adult

Body Description

Antennae: 2 long

Eyes: 2 fair sized

Tails: 2

Wings: 2 pairs–highly veined

Abdomen: 10 segments

Legs: 6 with claws on each

Mobility: clumsy fliers (females)

Size: up to 2 ½”, 30-50 mm

Hook Size: 4-8, 3X long

Females return several times to the water to deposit eggs. They will live anywhere from a few days to 1 week after depositing their eggs.