Portion of a Cabin of a Tractor

FIG. 1 is a right side elevational view of a portion of a cabin of a tractor, showing our design; FIG. 2 is a left side elevational view of the portion of the cabin of the tractor, with the right side elevational view being a mirror image thereof; FIG. 3 is a front elevational view thereof; FIG. 4 is a top plan view thereof; FIG. 5 is a bottom and front perspective view thereof; FIG. 6 is a top and right front perspective view thereof; FIG. 7 is an enlarged front elevational view shown within an area labeled VII in FIG. 1 ; FIG. 8 is an enlarged right side elevational view shown within an area labeled VIII in FIG. 3 ; FIG. 9 is an enlarged cross-sectional view of the portion of the cabin of the tractor illustrated in FIG. 3 , without showing the shape of the disclaimed portion; and, FIG. 10 is an enlarged top and right front perspective view shown within an area labeled X in FIG. 6 . All broken lines shown in the figures represent environmental structures and form no part of the claimed design. The enlarged right side elevational view is omitted, because the portion of the cabin of the tractor has the right-left symmetrical shape.