Yes, once again it's everybody's favorite Anodyne Recordings* superstars, the Tri'Tones!
This is, I believe, a still from their failed attempt to join the cast of The Beverly Hillbillies as a quartet of singing Bugtussle lovelies who come to visit the Clampetts. Either that, or they're showing their devotion to The Lawrence Welk Show by dressing up as Norma Zimmer.
In any case, it didn't get them far - for which I think we can all be grateful.
* A wholly owned subsidiary of Bland-Whitebread Amalgamated Enterprises.