Conchita

Singer popular enough to have posters in the Gay Desperado story (set in the old West) of anthology comic book Red Seal Comics #21 (October 1947). She only appears on a poster on the wall of the saloon where Rattlesnake Rose sings and Hoagy plays.

"Conchita" is a diminutive nickname of Spanish given name Concepción, so likely the singer is Mexican, as the story is comboy story set in the American Southwest.