The ornamental design for a bag in an envelope, as shown and described.
FIG. 1 is a top plan view of a bag in an envelope in an extended, open position, showing my new design;
FIG. 2 is a side elevational view of the bag in an envelope in a collapsed, closed position, the side elevational views being mirror images and the front and rear elevational views duplicative of the side elevational views;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a top plan view of the bag in an envelope in the collapsed, closed position;
FIG. 5 is a top plan view of the envelope portion of the bag in an envelope;
FIG. 6 is a top plan view of the envelope with the bag attached thereon;
FIG. 7 is a top plan view of the envelope partially closed with the bag therein;
FIG. 8 is a front elevational view of the bag in the completely closed envelope, the rear elevational view being a mirror image of the front elevational view;
FIG. 9 is a side elevational view of the bag in the completely closed envelope, the side elevational views being mirror images;
FIG. 10 is a bottom plan view of the bag in the closed envelope; and,
FIG. 11 is a top plan view of the bag in the completely closed envelope.
The broken lines representing stitching are part of the claimed design.