The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
|Option 1||Option 2|
|Dorsum of head light brownish yellow with numerous discrete, small, dark spots (sf 19.312) ||Dorsum of head with varied markings, usually darker than at left|
|Case cylindrical, made of longitudinally arranged sedge or similar leaves (sf 19.337) ||Cases of wide range of shapes and materials (sf 19.25, 19.442a–19.442c)|
|North||Widespread except not deep Southeast (i.e., not east of Texas or south of Arkansas and South Carolina)|
1 Example Specimen
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 is present.
- 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 segments.
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.
5 Example Specimens
This caddis is one of the most abundant caddisflies in temporary ponds of Glacier Park. The larvae build a round case of detritus and dead plant material that can get quite large.