Stonefly nymph (Genus Stenoperla) Stenoperla prasina

Kingdom: Animalia
Phylum: Arthropods
Class: Insecta
Order: Plecoptera
Family: Eustheniidae
Genus: Stenoperla
Species: S. prasina
Binominal name: Stenoperla prasina
Common name: Green stonefly

Stenoperla prasina is a member of Large Green Stoneflies (Genus Stenoperla). The nymph lifespan is about 1 year. 

“Early instar nymphs of S. prasina feed on diatoms and algae but later become carnivorous feeding mainly on the nymphs of mayflies, Deleatidium, Coloburiscus, Ameletopsis, and Oniscigaster, but also prey upon blepharicerids, chironomids, other small stoneflies, fish eggs and even upon their own species. Nymphs come out at night and actively hunt the substratum. They will not eat dead food but must have living prey, which is killed and devoured on the spot” (Helson 1934, Winterbourn 1974).

Stenoperla prasina 2-001.jpg

Green Stonefly Stenoperla prasina . 1.jpg  

Stonefly larvae possibly Stenoperla hendersoni.jpg 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/