Hi Gringo,

Spiders are just a "style" of wet fly, a wee wet without wings. The most simple form is just a thread or floss body and a soft hackle, like these:

http://i55.photobucket.com/albums/g142/ ... piders.jpg
http://i55.photobucket.com/albums/g142/ ... ndBlue.jpg

They probably represent a nymph or drowned adult, but oddly are not thought to represent an actual spider! Flies, go figure?

Anyway, so far we've not had any didymo in the north island (knock wood). I've heard reports that they think this particular strain may have a mutation that makes it even worse than usual. You definately do not want it in OZ. Entire rivers look like they've been filled with toilet paper, just devistating. There is some thought that a copper based substance may kill it without destroying everything else in the rivers. Some tests were tried a while back, but haven't heard anything more. Even if that works, it would be to "control it" and they don't think it would totally remove it from a river.

Donald Nicolson from Scotland has a great site that has a lot of information about this kind of fly. He posts on FAOL quite a bit and there's a link to his site as his signature.

- Jeff