I cannot find this census entry. I have tried my most clever searches without success. I give up and declare "no census entry" for this person. A small reward for the first to prove me wrong.

In the 1913 Supreme Court decision she was using an alias (Mabel Claire) and was operating a massage "parlor". The local eugenics club was trying to brand her an unfit person, so I assume that she was long separated from Fred Day and living on the fringe of society. This may explain her absense from the census.