Updated: May 13, 2021
(Or MiBS for short.)
Stephanie made this discovery much to our amusement, and this is just right up Princess Doraldina's alley. The original source are a couple of knitting pattern leaflets, published from 1968-75 by the Columbia Minerva Corporation out of Carlysle PA, which feature excellent vintage fashion and an amazing typeface.
And it is just what the title says: Men (or in this case A Man) in (a) belted sweater(s).
The most excellent aspect of this vignette are the many characters brought forth by the belted sweater each man is wearing. From the guy in the upper left who probably thinks this song is about him, to your high school french teacher (upper right), your best friend's older brother (bottom left), your best friend's older brother after he'd been married a few years, and your best friend's older brother going through a mid-life crisis.
The guy in the top center is either about to open up a can of whoop-ass, or knock Little John off a log. It's hard to say.
And the guys down at King Patterns also got in on the act with their version of Men in Belted Sweaters, though these two look more like Chaps in Belted Sweaters...
Out for a game of golf and up to no good whatsoever.
We would be remiss not to note that Men in Belted Sweaters is actually kind of a thing, or at least, a little bit of thing. Quatrina pays excellent homage to Men in Belted Sweaters on Deviantart:
Looking for a band name? Men in Belted Sweaters. You're welcome.