Tying is simple.
Body.......Pearl Core Braid
Hackle.....colour to match body?
You don't have to tie them as picture, you can tie them as the squirmies, you can even use the PCB to make "Daddies"
Hareline Dubbin co. or Funky Fly Tying have the material in at least two sizes.
you can make your own, but thats another story that i'm trying to put together.