Also on these boards
MB Boucher Pave and Metallic Enamel Bird Male Marvellous Spatuletail Hummingbird Pin
Like other MB Boucher pieces in 1941 marked Pat Pend, no patent was issued. Brunialti, American Costume Jewelry - Art and Industry (2008) Vol 1 pp 47-61, part of the 1941 metallic enamel series, designer Marcel Boucher.
1941 RARE Marcel Boucher MB LG 4" Rhodium Enamel Locust Grasshopper Pin Brooch | Sold for $ 1,234.56 on Ebay