The ornamental design for a necktie, as shown and described.
FIG. 1 is a front view of a necktie of my present invention having two upper sections that are fastened to provide a loop, showing the necktie as it appears before the upper sections are fastened around the neck of an individual;
FIG. 2 is a front view of the necktie of FIG. 1 showing the necktie as it appears after the upper sections are fastened to provide the loop;
FIG. 3 is a second front view of the necktie of FIG. 1;
FIG. 4 is a side view of the necktie of FIG. 1, the opposite side is essentially the same; and,