I was splitting an oak for fence rails and found this female. She was waiting for spring to emerge from the log. The cast pupal skin is the wrinkled tan thing to the right here. This wasp is in one family - Siricidae - of a larger group of primitive plant-feeding wasps which includes the several sawfly families. They don't sting. The female lays eggs into tree trunks and the larvae feed/burrow in the tree. Might be hard to tell scale here, but she is about an inch and quarter (~35mm) long.