This Skwala nymph still has a couple months left to go before hatching, but it's still a good representative of its species, which was extremely abundant in my sample for a stonefly of this size. It's obvious why the Yakima is known for its Skwala hatch.
Wbranch on Jul 24, 2007July 24th, 2007, 2:52 am EDT
On the WB but more often on the main stem of the Delaware I have seen sporadic emergences of a pretty large mayfly, maybe a #12, that has a deep yellow waxy colored wing and a tangerine colored body. I don't remember what color the legs or tails are so I can't offer more data for an identification but thought the size, wing and body color would be enough. They never seem to emerge in decent numbers and I can't ever remember seeing a trout eat one but I'm sure they must.
GONZO on Jul 24, 2007July 24th, 2007, 11:54 am EDT
I'd second Roger's ID as being most likely. They are one of the most beautiful mayflies. Though the golden drakes rarely hatch in great numbers, they can still be worth imitating. The rather unusual nymphs swim enticingly to emerge and can be worth imitating as well. I hesitate to mention it, but you can probably confirm the Anthopotamus ID by looking at the tails of the adults--the middle one is shorter than the outer two. Hey, as I've been known to say to my wife, what's wrong with looking at a little tail? ;)
Wbranch on Jul 24, 2007July 24th, 2007, 12:44 pm EDT
The next time I see one that is within reach I'll try and catch it to examine the number of tails. Where do you than get the colors of the nymph? Maybe it is in Selective Trout by S&R.
I just re-read Roger's reply and I thought Potamanthus Distinctus had an all yellow body and wing; see color photo in Art Flick's
"Streamside Guide" on the color plate facing page 81. Do you think their could be so much difference in body color that the bug I see on the WB could have a tanferine/salmony pink abdomen?
GONZO on Jul 24, 2007July 24th, 2007, 12:57 pm EDT
Yes. Even within a species, color can be pretty variable. (Just ask Konchu.) The colors you describe are not unusual, however. Sometimes this is expressed as a deep orange stripe down either side of the abdomen (and some members of Anthopotamus/Potamanthus are whitish). The nymphs are often a heavily mottled/barred tan and brown, and they have very prominent feathery lateral gills. (These gills would be worth imitating for movement alone, to pick up on your post about "Gills.") Hatches and Ames' Hatch Guide for New England Streams both have good pictures of the nymphs, as do several other more recent books. (Although, if you ask, Roger can probably post a picture for you.)
Wbranch on Jul 24, 2007July 24th, 2007, 1:22 pm EDT
Thanks for your adroit information. It appears that there are many bug men here with advanced insect knowledge. I've seen some humongous mayflies on the Susquehanna and always wondered what they were. From now on if I see any I'll try and catch one and photograph it to see if you fellows can identify it for me.