I believe this publicity still was from ~1930, shot during the filming of either Cocoanuts or Monkey Business. The four brothers pictured (L-R) are: Zeppo, Groucho, Chico and Harpo Marx. Also, the towering houseplant in back is named "Margaret Dumont," after one of their beloved movie foils!
To say a single word about the Marx Bros is to risk spending a few weeks fruitlessly trying to sum up their careers in as few essays as possible, but everyone knows how to use WP, and I'll also give you a little gag sequence that went on between Groucho and Chico--
The Sanity Clause: (4min)
https://www.youtube.com/watch?v=dbUDSxJFsDA
And now for something a little bit different! It's Mark Evanier's legendary blog, in which he tells many, many stories from the POV of a longtime writer for TV, comics, and a few other ventures. Most of those insider stories are based on his Hollywood and major USA comics work, plus some of his loves, like Broadway & theatre. His is one of the most 'high-signal / low-noise' blogs you'll every read about anything, so let's see what he had to say about Los Bros ~~Hernandez~~ Marx!
https://www.google.com/search?q=site%3Anewsfromme.com+Marx+Brothers
NOTE: some of the sadder entries are about his interviews and time spent with a fading Groucho (much, much later than in this shot)... which were not necessarily so pretty. :S
Aha, I've barely dived in to the Ritz Bros history myself. Thanks for the mention. I've cued up some highlights on YT and will take a look...
I'm also going to add the lovely "Sanity-Clause" video link above. Check it out if you can!