Not entirely sure what the story is here.
Horizontal pair of R196 or R207 used illegally for postage on a December 1914 cover. The cover appears to have originated in McKinney, Texas, althrough there is no return address, addressed to recipient in Mississippi.
I'm not sure how it routed through Mexico though. It was caught by the Mexican (postal?) authorities. The violet handstamp reads:
Recibida en el Departamento de Rezagos sin la estampilla correspondiente.
Which per Google translates to:
Received in the Lags Department without the corresponding stamp.
I don't know that "Lags" is a proper contextual translation of Rezagos.
The department name in the handstamp matches that of the black and white seal affixed (and unfortunately cut through when the envelope was opened), which overlays the McKinney handstamps, so clearly it occurred after the letter left McKinney.
McKinney is supposedly north of Dallas, so why would it have routed through Mexico to get to Mississippi?