Cover franked with diagonally BISECTED 1914 10c vermilion 'Transitorio' issue (SG CT5) tied by superb strike of O.P.A. No. 205 4a DEVISION SUP GUAYMAS. SON duplex cancel (Travelling post office on the Ferrocarril Sud Pacifico de Mexico line). Addressed to USA with LA CANANEA transit cds on reverse.