The ornamental design for a portion of an electronicmouse, as shown and described.
FIG. 1 is a front perspective view of a portion of an electronic mouse showing our new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a right side view thereof; and,
FIG. 7 is a left side view thereof.
The broken line showing of various regions in the Figures and the unshaded areas therein is for illustrative purposes only and forms no part of the claimed design.