Who is this woman?

This is a picture that I found in my Aunt Dot's photo album.  I know everyone in the picture except one lady.  I don't know the year, but my grandmother looks like she might be in her 70's, so maybe 1970's.  I also don't know whose house they were at.

From left is my grandmother Lucy Wait, my dad Dave Waite, my aunt Lucy Hubbard (my grandfather's sister), ???, aunt Lucy's son Bob Hubbard and daughter Nancy.

I have asked my aunt Dot and my aunt Esther if they knew who this lady is.  Neither one remembered.

I'm wondering if it was uncle Harold Wait's wife, aunt Tilly but I really don't know.

I guess now I'll never really know.  I wish I had paid more attention to details when my grandmother was alive.

****Update - In a Messenger text with Greg Hubbard in February 2015, I sent him this picture and asked him if he knew who this woman was.  He said that he was not 100% sure but he thought that it might be Aunt Marion Crawford (my grandfather's and his grandmother's sister).