This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn
- The mandible
is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae
on the ventral
edge of the hind femur
- Chloride epithelia
seem to be absent from the dorsal
side of any abdominal
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius
. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally
arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum
of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019)
. The species ID is based on Grammotaulius betteni
being the only species of this genus known in Washington state.