Unknown prelim by Sprouse

This light penciled prelim is on the back of the Catspaw sketch which itself is on a cut in half DC art board. I'm not sure if this prelim was from a Legion story or a Tom Strong story or what. It does look somewhat familiar to me but my memory isn't what it used to be.
I did darken the scan to make the art easier to see.

EDIT: Here's what Chris had to say on this prelim and the Catspaw sketch on the front:
This is actually my self-rejected unfinished model sheet for Catspaw, not a con sketch (but it does kind of look like a con sketch). Jason Pearson designed the character, and I was attempting to get a handle on her before I began my Legionnaires run. My second and final take (inked by Karl Story) was published in the back pages of one of the first three issues of Legionnaires, along with all of the other (20+) model sheets I did for all the characters . This is drawn on the back of another self-rejected unfinished piece, a page from a later issue of the DC mini-series Hammerlocke. Hope that clears it up a bit! --CS