Well, new to me. It's the egg case of a narrow-winged mantis. I was aware that most of our praying mantises are Chinese (although there is a native variety), but this is another that I had never heard of before - another that also comes from Asia, of course. I saw this thing as we were on our way home via the path along the edge of the hayfield and it looked like the material that a praying mantis egg case is made of, but totally different. So I pointed my Seek app at it and it said, after a little hemming and hawing, "narrow-winged mantis." I wasn't sure if that meant it thought the thing was an actual praying mantis or if it had correctly identified an egg case that I'd never seen before. Turns out it was the latter. This page has - quite a long way down - a comparison of the two egg cases.
So I learned something today. Never a bad thing! And once again let's hear it for Seek! What a handy tool.