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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GONZO on Apr 3, 2007April 3rd, 2007, 5:00 am EDT
This appears to be Acroneuria. Not sure which species.
GONZO on Apr 3, 2007April 3rd, 2007, 5:53 am EDT
Sorry, Jason--hasty judgement. This specimen appears to have a setal row across the occiput. Probably Paragnetina media. I'm not used to seeing a distinct "W" on the head of media, so this one threw me. But, I can't think what else it could be. (Way too dark for immarginata, and the abdomen would be patterned.)
Mlajoie
Posts: 6
Posts: 6
Mlajoie on Mar 18, 2008March 18th, 2008, 4:49 am EDT
This may in fact be media, but Gonzo is right, the markings are usually not this distinct (especially the 'w'). To me, this looks more like a darkly colored immarginata. Differences of habitat frequently cause variations in color, and it is tough to distinguish for sure, based on the photos. Immarginata has transverse banding on the abdominal terga, and this specimine has an especially dark abdomen, making it hard to tell. Also, just to point out, Gonzo, the occipital ridge is not made up of setae. It is a closely set transverse row of spinules. And to the other comment, a golden nymph will work fine for fishing, as it's still a perlid. Besides, I don't think trout can ID to species...
Entoman on Mar 11, 2012March 11th, 2012, 5:12 am EDT
Jason,
This one is still linked with Acroneuria for some reason, even though the name is now correct.
Two characters that nobody seems to mention are the concave look to the back of the head (caused by the occiputal ridge) and the exaggerated bowling pin shape of the abdomen on many Paragnetina. These are noticable differences from Acroneuria. When these two characters are together and obvious, there should be no need to look at spinules with a microscope or good macrophoto to determine between the two. We have a similar situation out West with Callineuria/Hesperoperla and Claassenia nymphs. Astute observers can easily tell the difference at a glance without enhanced vision, and I suspect this may also be possible between many if not most Acroneuriinae and Perlinae genera in the East.
This one is still linked with Acroneuria for some reason, even though the name is now correct.
Two characters that nobody seems to mention are the concave look to the back of the head (caused by the occiputal ridge) and the exaggerated bowling pin shape of the abdomen on many Paragnetina. These are noticable differences from Acroneuria. When these two characters are together and obvious, there should be no need to look at spinules with a microscope or good macrophoto to determine between the two. We have a similar situation out West with Callineuria/Hesperoperla and Claassenia nymphs. Astute observers can easily tell the difference at a glance without enhanced vision, and I suspect this may also be possible between many if not most Acroneuriinae and Perlinae genera in the East.
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
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