A fly stitch is also called Y stitch as it resembles the alphabet Y.
the stitch consists of up of a V-shaped loop fastened by a vertical
straight stitch. The stitch is often used as scattered stitch like grass
or in borders as a plant shape. When worked one upon other and in
branches, it takes a plant shape.
To work Fly stitch, bring the thread through the fabric out at the top
left of the line that is to be worked. Hold the thread down with the
left thumb and insert the needle a small space, level and to the right
of where the thread first came out. Make a small stitch downwards to the
center. With the thread under the needle, pull it through the fabric and
secure it in position with the loop.
The length of the fastening stitch can be varied to produce different
effects. The stitch best represents twigs and grass.