ST in YN describes types of haircuts in a 1930 issue.
Sam Taylor, "Taylored Topics" Y News, November 4, 1930, 2
Have you noticed them?—The group, or class, of society that shows its age and stability by the heighth of the hairline at the rear: Research has failed to disclose the exact geographic location from which its members hail, but suspision is that it is rural. All of the type have the neck shaved 'around' when getting a hair trim, and the ears are used a[s] guide lines. A young blood, somewhat of a rounder and hell-about-town has his hair line well above the ears in the rear[.] More conservative types lower it to the middle of the ears; and married men, mature members of society, earnest seekers after the light, and bankers, have but a scant half inch of smooth skin above the collar.