They are rather simple to tie once you get the hang of it. I prefer to use small bead heads to get them to sink quickly and hang vertical (important). The photo shows 3 different variants, the smallest I tied. Most should be in the 12-14 size range, at least that is my preference. For the body, I use very tiny larva lace, green or black are excellent colors. Add a tiny wire rib to give it some segmentation and flash. Dacron or ostrich make good gill immitations.
I second the recomendation for midge size lace or tubing. It's the stretchability and translucent aspect that makes the difference. The stretch allows you to build a subtle taper to a small, very thin chironimid larvae and the translucency allows you to use an under body to full effect.
The stuff I have been using is distributed by Hareline under the name "Micro Tubing". The Blood Red color is outstanding over white thread on a standard bronze hook.
Try it, you'll like it.
#8,10,12 Scud hook
Black tunsten bead head to size
Build a tapered underbody out of anything white to the head from the middle of the bend.Yellow floss ( I use the new stretch floss these days) and black v-rib wrapped together with one little tiny strand of pearl krystal hair to form segment to the head.
Currently don't have a picture of one but it's pretty straight forward.
it's a vinyl lace/rope type material , similar but not the same as larva Lace- only flat on one side , round on the other. Maybe it's sold under another name these days. Hell, I don't know. I just call it v-rib.