The ornamental design for a tractor cowling, as shown and described.
FIG. 1 is an enlarged front elevational view of the tractor cowling showing
our new design, the broken lines showing an exhaust pipe projecting
through the top of the cowling are for illustrative purposes only and form
no part of the claimed design;
FIG. 2 is a reduced top plan view thereof;
FIG. 3 is a reduced right side elevational view thereof; and,
FIG. 4 is a reduced left side elevational view thereof.