Quite the collectors piece from the 1930s! This is a really nice Reliance Products, "Little Colonial Sweethearts" with reverse painting techniques and the "Butterfly Wing" effect process. The information on the back of the pieces explains the process:

This truly beautiful creation is done is an exclusive hand process (right on glass) exactly duplicating the world famous "Butterfly Wing" pictures. The delicate colors transferred directly to the glass present a pearly quality which makes them spring to life, and the glass itself seems to radiate an elusive light.
Nothing has ever been offered before in America with such fineness of line, detail and rich coloring, and the "Butterfly Wing" effect process creates a brilliance not to be matched by any other type of decoration. In this very modern frame it will do credit to any room, and particularly attractive when hung in pairs.

This piece has such an awesome Americana vibe and perfect for the parlor, music room, or colonial décor. It would work wonderfully for the 4th of July or other patriotic themed shelf or mantel displays as well.

The background of the piece is camel colored paper and the glass has been painted on the underside in black silhouette with the "Butterfly Wing" process being applied in gold and silver. The back is cardboard with the detailed information stamped in the center. The original hanging cord is still attached.

The piece appears to be in excellent condition, leading me to believe it was displayed indoors, out of sunlight and really cherished. The wood frame is painted black with a gold inner accent. The frame shows a bit of it's age with scuffed corners and a dustiness to the black paint color. It is square and accents the piece well.

Dimensions:
9 3/4" x 12 1/2" x 1/2"