The ornamental design for a portion of a footbed, as shown and described.
FIG. 1 is a perspective view of a portion of a footbed in a used condition showing my new design;
FIG. 2 is a side elevational view thereof;
FIG. 3 is another side elevational view thereof;
FIG. 4 is a front elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is another top view of a portion of a footbed with the top portion of the shoe removed.
The broken line showing of portions of a shoe in FIGS. 1–7 is included for the purpose of illustrating only and forms no part of the claimed design. The broken lines which defines the bounds of the claimed design form no part thereof.