Giant Salmonfly (Stonefly)
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.