Hi,
A bit of a mystery for me:


A 3c Washington paid the correct surface rate to Toronto, but the 10c Special Delivery issue underpaid the 20c fee to Canada. The cover mailed from Boston to Toronto on JUN 14 / 1936 and arrived in Toronto on JUN 15 / 36.
The admonition reads: The admonition
"PLEASE ADVISE YOUR / CORRESPONDENT SPECIAL / DELIVERY FEE IS 20c IN / CANADA"Do you think that the admonition was applied in America or in Canada?
The cover also has an added 10c Canadian postage due label.
Best wishes,
Andrew[/left]