"Dark Grey Caddis"
Polycentropus
cinerus
free-living caddis larva
larva: 11-14 mm
These are unique netspinners that spin silken tubes and suspend them within the current, using hundreds of threads to hold them together . . . like an underwater cobweb.
Other
free-living caddis:
"Little
Orange Caddis" , "Medium Dark Olive
Sedge" , "Small Spotted
Sedge", "Western Olive
Sedge"