USA: 10c "Missing Propeller" Variety

This is Wiegand #4 (three-line admonition on back panel).

Below is a close-up of the indicum clearly showing the missing propeller, which was listed in the old Kessler catalogues. However, it is not in the Wiegand catalogue.
 

For comparison, here is the normal indicium 

There are other differences as well. Steve Levine has published a good start for further investigations on his website.


Reference:
Wiegand, Katalog der Aerogramme von Canada, USA, UNO New York, 1994