This is one of Gwilym's patterns, works equally well on stillwaters and rivers. Just hope I haven't missed a part off or I'm in for a hiding.
Hook: B100 or any curved hook to as small as you can tie them.
Thread: Black
Wingpost: Whatever you like to use
Hackle: Black.
Insert hook in vice, start thread and tie in an ant shaped body at the rear of the hook.
Varnish and leave to dry completely.
Restart thread between body and eye and tie in a parachute post, tie in hackle.
Wrap hackle and tie off, trim post to size, job done.
I've tied the hackle in slightly higher up the post so the body sits in/slightly under the flim, you can of course tie it where you normally do.