I attacked the problem of Boris Dolgov from a different angle and found one tantalizing piece of information. In a telephone directory of New York City from 1957, there is the following listing:
Boris Dolgoff, 630 East 14th Street, Manhattan
That address is in the East Village, a place for artists, musicians, students, and bohemians. Could that be the artist for Weird Tales? There were other Dolgov families in New York City in the early twentieth century. Maybe Boris was from one of them.
Dolgov appears to be a somewhat common name. The Dolgovs in America may have come from Belarus or surrounding areas of the old Russian empire. The name, if Google Translate is correct, means debts. Fitting for an artist.
Copyright 2016 Terence E. Hanley