Very likely ichnuman flies (actually wasps) and there are lots of them this year. There are many species and they are very colorful. I have seen some bright scarlet ones this year. I have seen more this year than ever. Do not kill them, they use the stinger to drill into larvae eating the inner bark of various trees and lay eggs.
Thanks for the info, glad I didn't kill the 2 I saw though it wasn't for lack of trying.
