[Evolution] One folder suddenly messed up

[Carpet Nailz <carpetnailz researchintegration org>]

One of my folders has somehow gotten messed up. About a month's worth of
emails are missing, although the titles show in the list of emails. But
when I click on the titles I get connected to a very different piece of
mail. That is, for about the month prior to when the emails are missing,
the titles in the email list aren't correctly linked to the emails: I
open an email with subject line saying 'x' but the title bar at the top
says 'y'.

I suspect that something went wrong when I was deleting trash--or moving
from this folder to trash.

Anyway I have a rdiff-backup that includes the entire .evolution folder.
But I'm not sure about the best way to go about restoring from that. Can
I just restore the one folder that has gotten messed up? (The mail
folders look like separate documents in the .evolution folder, but I
don't think they really are.)

Thanks.