Salmonflies
Pteronarcys californica
The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
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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.
- 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.
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Caddisfly Family Thremmatidae
This caddisfly family is important in the fall. Neophylax may be important nationwide, but Oligophlebodes is only known to provide fishable action in the West.
Where & when
In 189 records from GBIF, adults of this family have mostly been collected during October (34%), September (23%), August (15%), July (12%), and June (9%).
In 136 records from GBIF, this family has been collected at elevations ranging from 30 to 11191 ft, with an average (median) of 1880 ft.
Family Range
Specimens of the Caddisfly Family Thremmatidae
1 Female Adult
This large caddisfly looks really neat close-up.
3 Larvae
The size of the head compared to the body in this larva is surprising, and I think this means it's a fairly early instar of something which is going to get a lot bigger, but I'm not sure.
See the forum comments for notes on the identification of this specimen.
2 Underwater Pictures of Thremmatidae Caddisflies:
A variety of cased caddisfly larvae, probably mostly Neophylax, have clustered along the backside of a rock in fast water. There seem to be some Helicopsychidae larvae clustered along the bottom, and a few other taxa are mixed in. It's interesting that several larvae have especially large stones placed over the front openings of their cases, perhaps to block the case off for pupation.
It does seem to be the wrong time of year for Neophylax to be pupating, but that was the ID given for one of these which I collected and photographed up close.
It does seem to be the wrong time of year for Neophylax to be pupating, but that was the ID given for one of these which I collected and photographed up close.
A wide variety of caddis larvae and other insects have clustered together on the backside of this rock in fast water.
In this picture: Caddisfly Genus Neophylax (Autumn Mottled Sedge).
Start a Discussion of Thremmatidae
References
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.
Caddisfly Family Thremmatidae
Taxonomy
Genus in Thremmatidae: Neophylax, Oligophlebodes