Here are some photos,
The front hackle of the duns sits into the water supporting the thorax and the wings which lie above it,
the tails and body lie in the surface film supporting the fly.
Hope the above is clearer.
I've included a photo of the small midge patterns with detached bodies which I use. Size ? Around size 18
The hooks are Tiemco 212y which I find very good.
I've included a photo of the detached body sedges and detached body daddies , I use.
They are not my best because I've packed away some fly boxes in my house move.
As an aside, one problem with detached bodies is that the foam and thread connection can become broken either through
casting or by being chewed by a fish.
An easy way around this is to reinforce the detached body by taking a piece of monofilament, say 3-4lb strain,
and with a cigarette lighter slightly but one end to form a very small melted ball.
You then tie this into the centre of the foam detached body and then tie the completed detached tail including the nylon onto your hook shank.
I usually add a small drop of superglue onto the hook shank prior to tying in the detached tail with its central reinforced
core of nylon.
It really does make detached bodies significantly more durable