The Wasp and the HORNET!!!

So I opened up the window, to shoo out the wasp, and in flies... a hornet. So, I took the easy way out, went to Wal-mart, got a $2 can of spray, and that was the end of that. Kills on contact, gotta love it. checked to make sure, no nests out side, not sure where they came from, but apparently, I am not alone, the guy at wal-mart knew right where the spray was, and it was the last can. He said everyone is having problems with the red wasps (really not red, so dark maroon that it looks black until you get right up to it).