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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

Lateral view of a Psychodidae True Fly Larva from Mystery Creek #308 in Washington
This wild-looking little thing completely puzzled me. At first I was thinking beetle or month larva, until I got a look at the pictures on the computer screen. I made a couple of incorrect guesses before entomologist Greg Courtney pointed me in the right direction with Psychodidae. He suggested a possible genus of Thornburghiella, but could not rule out some other members of the tribe Pericomini.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

FISHN50 has attached these 7 pictures to aid in identification. The message is below.
FISHN50's profile picture
Metuchen NJ

Posts: 5
FISHN50 on Aug 25, 2011August 25th, 2011, 7:50 pm EDT
I want to thank all of you for I.D. ing the last 2 bugs. Like I said in the post I'm doing my first invertebrate study of a stream here in NJ that recently had a lot of stream work done on it. I want to get a count & an idea of it.s health & plan on continuing to do the sampling in different sections of the river in the next few yrs.
I can tell a mayfly from a caddis or stonefly but run into problems going any further on the I.D. I picked up a camera & it takes some pretty good macro photos so I intend on photoing most of the collected bugs. I also got a cheap digital microscope on E-Bay & will be using that as I get going.
This site is amazing & I want to thank you Jason for all the work you put into it. I look at it as a valuable resource & with your help & the rest of you fine fellow's help I'll be able to get most of the bugs I.D.
I have some more photos to post & would appreciate your further help.
If this is too much to ask just ignore my posts & I'll get the message

Taxon's profile picture
Site Editor
Plano, TX

Posts: 1311
Taxon on Aug 25, 2011August 25th, 2011, 10:00 pm EDT

Ignore you? Never!

1) Waterpenny beetle larva
2) Isonychia mayfly nymph
3) Isonychia mayfly nymph
4) Acroneuria stonefly nymph
5) Acroneuria stonefly nymph
6) Unknown caddisfly pupae
Best regards,
Roger Rohrbeck
Entoman's profile picture
Northern CA & ID

Posts: 2604
Entoman on Aug 26, 2011August 26th, 2011, 12:02 am EDT
Hi Neil -

The mayfly nymph photos are most likely Isonychia bicolor (Leadwing Coachman). Though there are other species, they are less common. They are all excellent swimmers.

The stoneflies belong to the Perlidae family and are probably Acroneuria abnormis (Common Brown Stonefly). The top one has molted recently, which explains the lighter color.

Any determination of the caddis pupa in the next photo would be pure speculation on my part (though I have my suspicions). Closeups of the frontal view head, dorsal abdominal, and anal processes would assist in determining the family, but to get to the genus level you will probably need to put the specimens in a covered container after shooting them to see if they will finish the emergence process. Then you can photo them as adults.

The last photo looks to be Maccaffertium mediopunctatum mediopunctatum, one of several Summer Cream Cahills (see edit). It was formerly classified as Stenonema nepotellum. By either name it is still one of the clinger nymphs of the family Heptageniidae.



BTW - That's a scud you have up in the corner of the caddis picture.

Edit: To correct the record, a recent conversation with someone I consider expert on photo identifying eastern mayfly hatches pointed out that the shape and number of posteriolateral projections (spines along the sides of the abdomen) precludes my suggestion and that this specimen is probably either M. modestum or M. ithaca. Between the two it's most likely the latter. Both are also Summer Cahills and pale as duns, so that part of the entry remains valid.
"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
FISHN50's profile picture
Metuchen NJ

Posts: 5
FISHN50 on Aug 26, 2011August 26th, 2011, 11:49 am EDT
Thanks guys

Grants Pass, OR

Posts: 302
Creno on Aug 26, 2011August 26th, 2011, 5:07 pm EDT
There are two caddis pupae in fig 6. The large one looks like a hydropsychid and the wing pads are black enough that is likely you can determine the species with a little work. You will need to carefully clear the abdomen (I use the KOH method) and then compare the private parts to figures in the literature.

The small one looks like a philopotamid. You should be able to determine genus just comparing it to the literature but maybe not species.

If ya want help just let me know.


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