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.
For example, here's a bit from one journal entry for late May on the Letort: "Noticed some larger 14?? tan caddis with green body. Pretty patterned wing. Long antenna. Green egg mass." Perhaps Eric will have some idea, but I was clueless as to what this might be.
Eric is mostly clueless but maybe a Limnephillid? Possibly Limnephilus rhombicus sorry I don't have a photo for the adult but here is one http://bugguide.net/node/view/190882/bgimage
Edit- I re-read your post Louis, and those Limnephilids are probably a little bigger than a #14. so it could possibly be Neophylax, but they may be a little smaller than #14. So like I stated before Eric is pretty much clueless...
Our late guru, Carl Richards finally decided to straighten us out here by explaining that what we thought, for years, was Chimarra was actually Brachycentrus lateralis. The Chimarra is more like a #20-#22...Our old hatch charts had the Little Black Caddis listed at #16-#18...Plus the really little Black Caddis hatches later in the year here than what we had listed...
I think Spence is right about this. I seem to remember other threads were Gonzo commented on this as well (including a lament on the misuse of the common name Black caddis). Still Grannom, just a different species if I remember right.
Here's my current breakdown for important PA species:
Brachycentrus numerosus--Penn's Creek Caddisfly, Dark Grannom, Dark Shadfly; adults have dark-mottled wings and dark blackish green bodies; pupae usually dark with green lateral stripes and dark wingcases.
Brachycentrus lateralis--Striped Grannom, Dark Grannom, Black Caddis; adults have dark wings and pupae are typically dark olive with tan lateral stripes and dark wingcases.
Brachycentrus nigrosoma--Little Dark Grannom, Little Black Caddis; adults/pupae are smaller and darker than numerosus.
Brachycentrus appalachia--Apple Caddis, Light Shadfly, Light Grannom; adults have very light tannish or grayish wings (almost white when freshly emerged) and apple green bodies; pupae are apple green with tan wingcases.
(Brachycentrus solomoni and incanu are also found in PA)
Most "grannom" activity in PA occurs from mid-April to mid-May. During that time, if you carry imitations of dark and light grannoms (adults and pupae) in sizes #14-16, you should have most bases covered.
The collecting record shows two Brachycentrus spp. for Huntingdon County--B. numerosus and solomoni. The record for Centre County shows four--B. numerosus, solomoni, lateralis, and the related Adicrophleps hitchcocki. And this is not including the smaller, but closely related Micrasema--five species listed for Centre County, and two for Huntingdon. Collecting records are often incomplete for any given watershed, but this does not mean that a species is not present. Neighboring Blair County, for example, has no Brachycentridae recorded; but, because it sits beside the heaviest concentrations of Brachycentrids in the state, I have to assume that this is just due to an incomplete record.
Brachycentrus nigrosoma--Little Dark Grannom, Little Black Caddis; adults/pupae are smaller and darker than numerosus..
the related Adicrophleps hitchcocki
And this is not including the smaller, but closely related Micrasema--five species listed for Centre County, and two for Huntingdon.
Mike did say that the larger "Grannoms" tended to cluster in bushes
I was on the famed Henry's Fork yesterday, and ate a lot of Grannom's.
Is it true that they taste like chicken?