I claim the ornamental design for a bowtie, as shown and described.
FIG. 1 is a perspective view of a bowtie, showing the new design.
FIG. 2 is a front plan view thereof
FIG. 3 back plan view thereof
FIG. 4 is a first end view thereof.
FIG. 5 is a second end view thereof.
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines of the bowtie strap depict portions of the bowtie that form no part of the claimed design. The broken lines along the claimed surfaces of the bowtie depict features of the bowtie that form no part of the claimed design.