13a In the old western US, homesteaders or farmers who settled in cattle-grazing territory (7) N?S?E?S 15a Also called lumbus, the part of the lower back and sides between the pelvis and the ribs (4) L?I? 19d Short poem with only two rhymes throughout and the opening words used twice as a refrain (7) R?N???U 26a Screening procedure that enables a doctor to predict the likelihood of a woman developing a particular form of cancer (5,4) S?E?R???T