The Hydropsyche, together with its greenish Caddis cousin Rhyacophila and unrelated but similarily shaped Gammarus is one of the most often cited inspirations for the Czech nymph fly style. This is not entirely unreasoneable.
The pic shown above is of a dead specimen - the living critter is too active to stand still while being photographed with my limited equipment - but its pose is not unnatural. You can see where the C shape of the CZN hooks comes from :)
I have come to conlusion that the right way to imitate in fly fishing is not to slavishly copy each body part of an insect in its static form, but to reflect on its main features and design an impressionistic imitation. This is why I decided not to reproduce such things as gills, head and leggs.
Not to mention that I learned the hard way a most profound truth of nymph fishing: you are going to snag; mabye sooner, maybe later, but you are gonna lose that fly. A dispensable fly is a must. This is what I came up with.
#8 Skalka Gammarus hook
a layer of flat lead
tan tying thread
rootbeer colored Sybai shellback
0.16 mm spining line as ribbing
beige rabbit dubbing for abdomen
home made mixture of hare and fox squirrel for thorax / legs
a light touch of black marker to finish