U.S.A.-1933 Imperforate Minisheet-A Century of Progress-Souvenier

Illustrated below is a partial minisheet issued in 1933 in compliment to the American Philatelic Society, in convention at Chicago from August 21 to 26 1933. The sheet was issued in lots of 25 and this sheet has been cut leaving only 12. Two sheets were issued, the other (also of 25 stamps) showing the Federal Building in the city of Chicago.