This is an appeal in forma pauperis from a denial of a motion under 28 U.S.C. § 2255 to correct an allegedly illegal sentence. Appellant has served the sentence of three years imposed on him on his plea of guilty to Count I of a three count indictment charging the illegal transportation of aliens. 8 U.S.C.A. § 1324(a) (2). Appellant also pleaded guilty to Counts II and III, and was sentenced to two consecutive terms of two years each, to be served consecutively to the Count I sentence.

Each indictment of the transportation referred to one time, one auto, one origin, and one destination, but referred to three individual aliens. Appellant urges this can be but one offense.

The statute to which appellant entered his pleas, itself specifically provides that transportation of each alien shall constitute a separate offense.

The appropriate punishment for a particular federal offense is a matter subject only to the discretion of Con *241 gress, provided no constitutional limitation is violated. Bell v. United States, 1955, 349 U.S. 81, 75 S.Ct. 620, 99 L.Ed. 905. When Congress clearly defines the unit of prosecution, the courts cannot intervene, nor by “interpretation” change the law.

We have heretofore passed on this same appellant’s identical claim. We affirm what we have previously said, Vega-Murrillo v. United States, 9 Cir., 1957, 247 F.2d 735, and we affirm the district court herein.