The ornamental design for a housing for a meteringpump, as shown and described.
FIG. 1 is a front view of a housing for a metering pump showing our new design;
FIG. 2 is a back view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a right side view thereof; and,
FIG. 6 is a left side view thereof.
The broken lines in the drawings are included for the purpose of illustrating portions of the housing for a metering pump that form no part of the claimed design.