As I prepared to set foot for the first time in the Catskills' storied Esopus Creek, I noticed an Isonychia bicolor nymph crawling out onto a rock at my feet. I pulled out my handy little camera and started snapping pictures.

This process isn't as interesting to fly fishers as the emergence of a dun from a nymph on the water's surface. This is a point in the mayfly's development at which it's temporarily safe from the trout, but it's interesting to watch up close anyway.

Several craneflies formed a mating cluster here in a dark rootwad along the bank of a large limestone trout stream.

I'm not sure what these clusters of grannoms are doing lying dead and mostly upside down in clusters on the rocks.  Anyone have an explanation?

Here's a fresh ball of eggs from a Hendrickson spinner, photographed to show the proper color for the egg-ball on spinner patterns.
The underside of a freshly emerged Ephemerella invaria dun.
This Ephemerella invaria sulphur dun got stuck in its shuck trying to emerge.  This isn't exactly a "natural" pose for a photograph, but it kind of shows what an emerger pattern could look like.
I saw something strange flying around near the streambank, fluttering on and off the water's surface, so I went to check it out.  I didn't recognize the wing profile in flight, and it's no surprise!  These two caddisflies were joined mating, and they were very reluctant to let go.