This short-legged version of the union suit doesn't seem to show up much past the 1920s. I'm still waiting for an expert on vintage men's underclothes to stumble across this blog and explain all the things that I can't quite fathom.
One of my Women's Institute books of this same period recommends that if making these in quantity, one buy a knit men's undershirt and cut it up to use for the back waistband. This is an extremely sensible idea.
It's interesting to see this garment made up in prints and stripes. From a sartorial perspective, was it acceptable for a gentleman's print undergarment to show through his white shirt?
At this time McCall didn't offer a separate instruction sheet, but printed some minimal instructions on the pattern pieces themselves, must as Pictorial Review did.