French Colonies. (Guyane). 1937. Air Mail envelope addressed to 'Post Restante, Cayenne, French Guyane' bearing France Yvert 189, 15c brown-lilac, Yvert 283, 50c rose (2) and Yvert 311, 2f blue (4) tied by Barsac/ Gironde date stamp '13th July 1937' with 'Par Avion' label and Guyane Francaise Yvert 117, 30c pale green applied and tied by Cayenne/ Guyane receiver '31/7' on face. A very rare item of postage due mail from French Guyane.