My guess is that this was a third grade of gasoline of lesser quality than "premium" or "regular" Most major oil companies had such gas grades in the 30s. Note the needle kit also says "Marathon Oil Co." Ohio Oil Co. used that name for what was once Transcontential Oil for about 5-6 years, before selling off their refining & marketing operations in that part of the country. Road maps from 1931 & 1933 read "Marathon Oil Co., but the 1937 issue it becomes "Ohio Oil Co." The change would have come somewhere between 1933 & 1937.
BTW...There was once a BLUEBONNET beer produced by the Dallas-Ft. Worth Brewing Co. in Dallas. The only cans produced are quite rare and go $400+ in can collecting circles!!!