CH 1938 B1y Pro Patria FDC ill. no address

Switzerland 1938 B (Swiss National Fête and PRO PATRIA - issues)
Tellskapelle at Lake Lucerne, smooth rubber, SBK B1y, Michel 326y,
FDC illustrated cover without address, 2 stamps cancelled "15.VI.38 Schweiz. Postmuseum BERN", in excellent condition.