The ornamental design for a portion of a mudflap, as shown and described.
FIG. 1 is a perspective view of a portion of a mud flap showing our new
design, the broken lines are shown for illustrative purposes only and form
no part of the claimed design; and,
FIG. 2 is a rear elevational view thereof.
The front, top, bottom and side views of the design are not visible in
their normal intended use.