Doing research this morning I came across an image from Claire McCardell, an all time favorite designer of mine, which I dont recall seeing before. Caption partially reads" pique bathing suit costume with its inseparable sunbonnet." It makes me happy when I see animage and I know exactly who the designer is. Claire has played with the 'sunbonnet' or scarf/headress treatment throughout her career.
Here's another from her that sports something similar, this one from 1954. I'll take one of each please!