Crossed buttonhole stitch
Leaving a loop on the surface, bring the needle up in line with the base ensuring the needle comes to the surface left of the loop.
Take the needle down by crossing over the last stitch, again leaving a loop on the surface.
Structure of stitch
An effective border or edging stitch that can also be used for filling.
Mary Thomas’s Dictionary of Embroidery Stitches (1934) , p.22