Lay a thread base all the way back to the start of the bend, using a thread colour that matches the body colour you are going to use.
Catch in three pheasant tail fibers for the tail with a pinch wrap or two, held on top of the shank, a little longer than a hook gap. Roll the fibers in your fingers first to break them apart.
Take loose wraps forward over the butts to form the underbody, then run the thread halfway back and forward again to build a slight taper.
Prepare the vinyl D-rib: singe the tip and pull it away quickly so it draws out to a flat spot, which lets you tie it in without a lump. Catch it in back at the bend with the rounded side of the D facing up.
Wrap the D-rib forward in touching turns over the back half to two-thirds of the shank, pulling hard on the first few turns and easing off toward the front so the body swells slightly. Secure with about four wraps so it cannot come undone, snip as close as you can and squash the stub smooth.
Tie in ten to twelve pheasant tail fibers at the front of the body as the wing case, then add a few extra wraps to ramp the step down so the thorax wraps go on easily.
Wax the thread and dub a thick, tight thorax of hare's mask - pull guard hairs from the base of the ear and mix in softer fur from the cheek. It may take a couple of applications to get it thick enough.
Pull the wing case forward over the thorax, secure with a couple of wraps and snip close. Sweep stray fibers back, take the thread to the eye and build the head back up into a ramp. Whip finish and add a drop of head cement.
Brush the thorax out with a dubbing brush, toothbrush or a velcro stick - be rough with it - to pull legs out of the thorax, and pluck out any that finish too long.