This was a suit to collect an undercharge in express rates upon interstate shipments of strawberries. It was brought more than two years, but less than three years, after the shipments were made.

The defenses were: (1) Prescription of two years under the Louisiana statute; and (2) estoppel, in that appellant had settled with the farmers whom it represented upon-the basis of the rates charged and collected as the shipments were made.

As these were interstate shipments, the state statute of prescription does not apply. Suit within three years from the time the cause of action accrued is authorized by act of Congress. USCA tit. 49, § 16, par. 3(a).

The carrier was bound to collect the legal rate, and a shipper who has paid less cannot invoke the principle of estoppel. Pittsburgh, etc., R. Co. v. Pink, 250 U. S.. 577, 40 S. Ct. 27, 63 L. Ed. 1151.

The judgment is affirmed.