My house is 200 feet from the river bank, and so attracts a few mayflies if lights are on in the evening.
The night before last, some dark colored duns came to the screens. 36 hours later, they are molting into spinners. I measure this one as 0.42 inch long (Dark Hendrickson ?).
Now today we have a few samples of another species, 0.34 inch long (Sulfur ?)
Very cool. I love the pic of the dun molting into a spinner.