Catchstitch
This stitch allows a certain amount of elasticity in a seam and is often used in hemming. It is formed by criss-crossing the stitches over two pieces of fabric butted together.
Work left to right. Secure the thread and take the needle in a little stitch from right to left on one edge. Take the needle through the second fabric edge from right to left, forming a diagonal stitch across the open seam. Keep stitches consistently spaced.