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Photo#286065
Salmonfly? - Pteronarcys

Salmonfly? - Pteronarcys
Thornton, Grafton County, New Hampshire, USA
June 6, 2009
Size: 50mm
Pteronarcys dorsata?

Moved
Moved from Stoneflies.

Interesting. a few weeks befo
Interesting. a few weeks before seeing the adult I found a number of Pteronarcys nymphs on the same river about 8 miles upstream. My 5 year old daughter was treating them like little kittens- letting them crawl all over her, etc. I was frankly freaked out a bit myself at first as they had scary looking spiney type appendages along its sides.

Maybe comstocki that you are referring to. I'm going to take a walk around that nymph siting area and near the place I saw the adult and see if I can find some shucks. I'll report back if I find anything. thanks for the inspiration.

Pteronarcys
P. dorsata would be likely if this came from a large stream or river. P. biloba and P. proteus inhabit somewhat smaller, colder waters (with proteus usually upstream toward the headwaters). P. comstocki is another species that is found in the Northeast, but it doesn't seem to be nearly as common as the others.

 
thanks Lloyd, It came from a
thanks Lloyd,
It came from a cobble dominated 5-6 order river (100 square mile drainage area) so I'm not sure if it rules in or out P. biloba and P. proteus. It was crawling out along a bar in broad daylight (don't know if it emerged in the night as I understand P. dorsat to do). River temps reach 73 degrees F once or twice a year and the stream is relatively nutrient poor.

I have since found out from a co-worker who grew up near the canadian border that this is the only type of stonefly he ever saw growing up.

thanks again for narrowing down the range

 
You might want to try checking for nymphs
P. dorsata seems like a good possiblity, though I'm not sure that P. biloba can be ruled out. Even though dorsata, biloba, and proteus can sometimes be found in the same watershed, there's usually not much overlap--dorsata is typically downstream in larger, warmer waters, with proteus upstream near the headwaters, and biloba somewhere between.

Unless you can carefully inspect the last few abdominal segments, the nymphs are easier to identify to species than the adults. Nymphs of biloba will have pointed projections ("knobs") along the sides of the abdomen up to and including segment 8, but the knobs will be absent on dorsata. P. proteus has the pointed knobs diminishing or disappearing around segment 7 and has a more squarish pronotum with less "pinched" corners. The knobs along the abdomen of P. comstocki are shaped like long, fearsome-looking spines, and it has a pointed projection on the mesonotal wingpad. Of the possibilities, proteus and comstocki would seem least likely to me.

(You could also try looking for the shucks of the nymphs. Although I sometimes find them on rocks, Pteronarcys shucks are often found on the trunks of streamside trees, sometimes as much as 1'-3' up from the ground.)

 
should have replied to you- my goof
Interesting. a few weeks before seeing the adult I found a number of Pteronarcys nymphs on the same river about 8 miles upstream. My 5 year old daughter was treating them like little kittens- letting them crawl all over her, etc. I was frankly freaked out a bit myself at first as they had scary looking spiney type appendages along its sides.

Maybe comstocki that you are referring to. I'm going to take a walk around that nymph siting area and near the place I saw the adult and see if I can find some shucks. I'll report back if I find anything. thanks for the inspiration.

 
Please do report back...
and if you locate some of the nymphs with the scary looking spines (comstocki), I'm sure that photos of them--even the evacuated shucks--would be welcome additions to this site, as would photos of dorsata.

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