The ornamental design for a mailbox, as shown and described.
FIG. 1 is a perspective view of a mail box showing my new design, and
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.
The side opposite that shown in FIG. 1 is substantially a mirror image
thereof while the bottom and the rear of the mail box is substantially
flat and unornamented.