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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It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.
I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.
The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.
Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.
The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.
Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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PaulRoberts on May 4, 2012May 4th, 2012, 8:10 am EDT
This tiny little caddis larva was pumped from a small canyon stream brown trout stomach:
From the curled abdomen I was guessing it's Helicopsyche. Why is it out of its case? It looks too intact to have already had the case digested, although maybe the silk bound sand grains dissolve quickly. They shouldn't drift case-less as I believe they continue adding on the the same case. Anyway, thought I'd share it.
After looking at images of Helico, it doesn't look like it is. Too young to tell? It's tiny, like #28. Heck of a set of grippers eh? How about a very young Rhyacophilia -colors are right for it?
From the curled abdomen I was guessing it's Helicopsyche. Why is it out of its case? It looks too intact to have already had the case digested, although maybe the silk bound sand grains dissolve quickly. They shouldn't drift case-less as I believe they continue adding on the the same case. Anyway, thought I'd share it.
After looking at images of Helico, it doesn't look like it is. Too young to tell? It's tiny, like #28. Heck of a set of grippers eh? How about a very young Rhyacophilia -colors are right for it?
Creno on May 4, 2012May 4th, 2012, 1:41 pm EDT
I have never seen a green bodied Helicopsyche larva and legs don't look right. Do you think those black areas at apex of abdomen are large and sclerotized? If so, that is too many for Rhyacophila. Was it Bear Creek? lateinstar Leucotrichia?
PaulRoberts on May 4, 2012May 4th, 2012, 2:39 pm EDT
This is the only image I have. The end of the abdomen looks sclerotized to me. It was from Middle St Vrain canyon at about 6500ft -the trout from a seething pocket water pool. Late instar would seem timely wouldn't it? Leucotrichia? But the abdomen is not very wide.
Here's an image of a Leucotrichia:
http://www.dfg.ca.gov/abl/lab/CA_digital_ref_level1_Leucotrichia.asp
Here's an image of a Leucotrichia:
http://www.dfg.ca.gov/abl/lab/CA_digital_ref_level1_Leucotrichia.asp
Entoman on May 4, 2012May 4th, 2012, 8:41 pm EDT
I don't recognize any of the genera mentioned in this specimen. The size really throws me for a loop. Size 28? And the dorsal plates could go beyond the last two for all we can see...
"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
Creno on May 5, 2012May 5th, 2012, 12:35 pm EDT
Sorry, by late instar I did not mean last instar. Should have said penultimate. And as Kurt implied - size already helps. Early instar caddis in general look quite different than the final instar. Early instar hydroptilids are no exception and have the typical, slightly tapered caddis abdomens rather than the enlarged abdomen. Very few figures/pictures are available in the NA literature. Do you have access to Hicken 1968? Wiggins 1996 has Leucotrichia.
In your specimen there looks like more than the single sclerotized apical plate typical of Rhyacophila. That led me to Leucotrichia, or a terrestrial larva like a beetle. If you don't have the specimen we will never know.
In your specimen there looks like more than the single sclerotized apical plate typical of Rhyacophila. That led me to Leucotrichia, or a terrestrial larva like a beetle. If you don't have the specimen we will never know.
PaulRoberts on May 5, 2012May 5th, 2012, 4:39 pm EDT
I don't have the specimen. Nor Hicken. It does look like there are more than a single apical plate. The size is what surprised me. Leuctrichia is probably best bet, but we'll never know I guess. Thanks for the responses guys.
Entoman on May 5, 2012May 5th, 2012, 11:57 pm EDT
The earlier instar would also explain the lack of case as well, Paul. As to what it is, I'm no closer than I was before and I wouldn't hazard a guess as to genus, but I do agree with Dave that it's probably a hydroptilid (Microcaddis) of some kind.
"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
Entoman on May 6, 2012May 6th, 2012, 12:27 pm EDT
On second thought, Dave's genus suggestion is a good one. I forgot the other common genera (Hydroptila and Agraylea) like slower water.
"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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