What mayfly

[Steve S]

Was up on a ridge at a friend's place in Occidental, CA in October when this mayfly blew in the house and landed on the wall.
Am pretty sure it is a Callibaetis, but not sure of the exact species. Any thoughts?

[Bill Kiene semi-retired]

You might be right......the adult usually has a completely modeled wing and the spinners have that modeling on the leading front edge?

[corytay]

Have you found some information online. You can try to search using Google Images search.

[Bill Kiene semi-retired]

What size was it? #14, 16, 18 or 20?