Mid 1920s.
Here's a nice photo from Shorpy from 1920 showing what was probably a purchased bathing suit made of knitted fabrics. By now we've definitely abandoned the earlier dress-and-bloomers style that we saw in May Manton 7853 but some sort of skirt is still thought necessary.
For this pattern the designers recommends Jersey for the "tights," as they're are calling the undergarment. At this time Jersey would have been a fairly sturdy knitted fabric of wool. Recommendations for the "apron" include taffeta, shantung, satin, printed crepe and crepe de chine.
The print on view A looks very much like Egyptian hieroglyphics to me.
As it happens, King Tut's tomb had been discovered by Howard Carter in 1922, and worldwide Egyptomania promptly ensued.
