Insect Order Ephemeroptera (Mayflies)

A couple Sulphur (Ephemerella invaria) nymphs cling to a log.

In this picture: Mayfly Species Ephemerella invaria (Sulphur Dun).

There are several species of caddisfly larvae and Ephemerella nymphs on this rock.

In this picture: Mayfly Species Ephemerella subvaria (Hendrickson) and Insect Order Trichoptera (Caddisflies).

A large Ephemerella subvaria nymphs clings to a log along with a couple smaller mayfly nymphs.

In this picture: Mayfly Species Ephemerella subvaria (Hendrickson).

Here's the surface of the river viewed from below during a Tricorythodes spinner fall. Several dead spinners are visible.

In this picture: Mayfly Genus Tricorythodes (Tricos).

This is a pretty clear photo of an Epeorus nymph clinging flat against a log. The big mound of debris on the bottom center of the picture, attached to the light rock, is a structure that's been puzzling me. I've found several in one section of the river. It's big, like 2 inches long and maybe 1/2-3/4 inch wide/tall, and hollow, like some sort of coccoon or something. It's clearly a structure built by some sort of little creature, but I'm not sure what.

In this picture: Mayfly Genus Epeorus (Little Maryatts).

Several fast-swimming Siphlonurus nymphs blend in very well with the silt in this slow backwater along a trout stream.

In this picture: Mayfly Genus Siphlonurus (Gray Drakes).

There are a couple Epeorus mayfly nymphs clinging to this rock. One interesting thing I've noticed is that even though the stream has a lot of clingers, they rarely show up in my photos, and I've started paying more attention to the river bottom while I'm fishing I've noticed that clinger nymphs generally see or feel me coming and scurry to the undersides of their rocks before I can get in picture range. I think I have the same problem with stoneflies.

In this picture: Mayfly Genus Epeorus (Little Maryatts).