A New and Unwelcome Biting Fly

It's a fly, the same size as a common housefly, with a green-speckled abdomen. They are quite persistent and bite like a deerfly or horsefly. It will fly into your kayak and bite your legs. I only encounter them when I'm on or near the water. I've never seen them before this summer.

Does anybody know what it is?

Stable fly.

Pretty common out on the water at times.

Quick aren't they?

Everything matches up except the appearance. The flies I'm talking about (emerald-green dotted abdomen) don't look like stable flies (striped abdomen) and they aren't in my Audubon field book.

Hmmmm, Don't know then.