I'm starting to lean toward hooks with a straight eye for Pupa. And of course Scud hooks are good, nice curve simulates wiggle. And tie em on with a loop eye on your leader, a Garcia knot I think it's called. Gives the fly more freedom to wiggle, but still hangs straight down.
There are numerous theories on what fish see in a chironomid. The only theory I
adhere to is carry lots of Size/Color patterns and switch till you get on the bite. I catch many fish on black wool with a white everglow rib. No flash at all.
Often though the fish will prefer a little translucence and/or flash. I don't often find great bites on chromers, but I do like LiquidLace for translucence. Also other plastic wrapswith mylar ribs for flash and coated w/superglues will often outproduce "plainer ties".
But it's all up to the fish and the combination of Water clarity,sun conditions,and current
hatch size and color makes for infinate variation of what they want to see. It's amazing.
I'm no pro at figuring it out. I carry lots of variations and go through a color/size routine untill I get on some action. I often use those little shepards hooks when I'm searching....allows you to change flyz fast and still the fly swings free.
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If you can't go fishing today,
At least talk fishing!