http://www.theflystop.com/page/page/4433054.htm
I've used several of these patterns to great effect, particularly the hydropsyche. If I remember correctly from Borger's Presentation they're much more widespread than the net-builders (the green rockworm) which tend to be the bright green caddis larvae... I think those are to be saved for very cold waters, headwaters, etc. I think he said the hydropsyche is the most commonly occurring caddis larva, not necessarily the most abundant in any one stream, but in the most streams.
I know aaron has a cased caddis pattern that is killer in PA. Those larvae are also green.