Airmail cover with oval 'Norman Stocks Asuncion' imprint on flap franked with 1927 1p scarlet and 1p 50c lilac (SG 303 & 306) tied by diamond 'ENSAYO SERVICIO AEREO INTERNO' cancel with SCIO AEREO POSTAL PARAGUAY 4 SET 30 cds alongside. Flown on the ASUNSCION - TOBATI trial flight with TOBATY arrival cds dated 5 SET 1930 on reverse. Rare. (Muller unlisted).