This is surely the most distinctive-looking species in Ephemerellidae. I like the rugged, spindly look. If mayflies made movies, Penelomax septentrionalis would probably play the supervillain. Maybe I should take a break and get something to eat.

I captured this specimen in the same color as this photograph, during its egg-laying flight. The emergers are much lighter.

Several users have interesting comments in the discussion of this specimen, but this observation by Creno is especially good: Also, this is what I would call an "immature" pupa. The wingpads of caddis pupae darken to nearly black as the enclosed adults near emerging. The darkening is the developing adult wing inside the pupal wing pad. The ultimate coloration of the adult wing is not very apparent in most pupal wing pads as the majority of the adult wing coloration comes from the color/position of the adult wing hairs and setae. But dark pupal wingpads are a good indication that the emergence will occur very soon, likely that day or so, and that the adult parts are sufficiently developed within the pupae to make a species determination from the specimen, particularly if it is a male.

This yellow drake dun hatched out of my aquarium over a month before her brethren in the wild are slated to emerge. She seems a bit small, and that might be the reason.

I photographed this nymph in the middle of molting between one instar and the next (not hatching).

Based on the pale longitudinal forewing veins (excepting the costals), dark middle terga, and genitalia (Burks '53), this specimen is P. adoptiva.

This spinner and hundreds of others like it were dancing over the road through a very narrow valley carved by a tiny, steep tributary of the trout stream I was fishing. I got strange looks from a few passers-by, standing around on the road with a butterfly net...

I collected this specimen along with a female dun of the same species. Unfortunately it's not in very good shape. After poking at it for a while under a microscope with a good scientific key in hand, I'm pretty sure this is either Leptophlebia cupida or Leptophlebia nebulosa. I can't tell which.

I collected this mayfly after user Al514 tipped me off to the presence of some Leptophlebia mayflies I didn't seem to have yet with his ID request of a male dun. This seems to be of the same species. I also collected a female spinner. Based on that spinner, I can tell that this is either Leptophlebia cupida or Leptophlebia nebulosa, but I can't tell which. Unfortunately none of the specimens I collected made it through the hot, sunny day very well. So the pictures aren't great, but they're better than nothing.

This seems to be a mottled sculpin, Cottus bairdi. Normally this species is more mottled.

This specimen isn't in the best of shape, as it's missing all three tails, but it's the only one of its species I captured in this sample.

This is one of the most vividly green Hydropsychidae larvae I've caught.

This specimens shows that the name "green rockworm" doesn't quite fit all Rhyacophila larvae, even though it does fit the majority. This is actually the first of their larvae that I've found in a different color. I'm not sure if it's because of the species or because this is a young one, but I have found equally small green larvae, so I'm guessing it's the species.

I think this is a pretty early instar Ameletus nymph. It's certainly a striking one.

The size of the head compared to the body in this larva is surprising, and I think this means it's a fairly early instar of something which is going to get a lot bigger, but I'm not sure.

This one got a little bit damaged in the abdomen when I extracted it from its case. That's a delicate job.

Even though I already have pictures of a Rhyacophila pupa in its cocoon, I took this one and then tried to keep the pupa alive, hoping to photograph it in several stages of development. That didn't work out; it seems to have died without changing much. Oh well.

The closed-off case opening suggests this one was already beginning to pupate, which also explains the unusual shape. I damaged it a little bit getting it out of its case.

This is either Neoleptophlebia or Paraleptophlebia; I know of no way to be sure from a female dun alone. The genus is only a guess based on the fact that I found more Neoleptophlebia nymphs in the general area.