I again urge you to read some books about flyfishing and fly fishing theory
before just trying to copy flies from pictures in flytying books, You need
to understand that somewhat similar apperance does not equal similar
performance or function. For instance, trimming the hackles may give a
somewhat similar appearance (to the human eye at least) to a proper
Griffith's Gnat ( though the overall fly is still several sizes larger than
it should be). but the thick blunt tips of a trimmed hackle will not ride
properly on the surface, will appear wrong to the fish, and will quickly
absorb water and sink.
Even if "genetic" hackles are not available to you in China, you can -
though with some difficulty - find hackles of the proper size. You just
need to be more diligent in your search. A few can usually be found near
the head of good rooster skins. Many of the fly patterns (including
Griffith's Gnat) you are trying to copy originated long before "genetic"
hackle was developed, and several of us on this board are old enough that we
sucessfully tied such patterns for many years before we could get - or
afford - "genetic" hackle.

Bob Weinberger La Grande, OR

I understand your point. Next time I will use the right hook for the
right pattern. You know, even you can read a lot of books, if you do
not try to tie it you can not completely understand it. It is the
reason i tie those flies and post them on this forum. I think I have
to get through it by the following processures:
1. get a general idea about fly fishing and fly tying
2. tie some flies to test myself whether i have understood the theory
or pattern in the books
3. post it and read comments to recheck my understandings about fly
fishing and fly tying
4. redo the pattern
5. receive the comments again
6. then i can have a relatively clear mind to know what to do and how
to do
You know, there are few issues which never mentioned in the books like
how many wrap of hackle should be for a pattern. If you wrap too much
some one will say that you have overdressed the pattern. If you wrap
too small, the pattern will not sit on the water as it should be(I
sometimes put the fly on the water to test whether it will sink or
not). All those hints you can only find them when tying them because
it is not math and it does not have clear rules. Copy pattern is only
the first step to get to know more about it. It is, what i think, i
should do. As a Chinese mailand guy, i do not have the fly tying
circumstance around me, it is another reason i have to post my
patterns in this forum to receive your guys comments. Fly pattern is
not only a commercial products, but also a representation of culture
for me. i can feel the connection between human and natural. i hope i
could completely understand it before being buried into the ground.