Blue Winged Olive
Hook: TMC100 #16-22/TMC101 #16-22
Thread: Gray, tan, brown, olive, rusty dun 8/0
Tail: White or medium dun microfibits (splayed), hackle fibers to match
Dubbing: Gray, olive gray
Hackle: Medium dun hackle/light dun hackle
Post: White Z-Lon, white calf tail, gray or white poly-pro yarn (pink also for a better visual)
Comments: This is a versatile fly in southeast Minnesota when tied in a variety of colors and sizes. It is tied parachute style for a variety of reasons - visual being one of them. BWO hatches are predominant early in the season in mid-March throughout the spring and into summer and begin to peak again in September. It is mainly fished in #18 & #20, but a hatch of #16 Blue Quills is a possibility as well. This is a must have for early season fly fishermen in our area.
In terms of tying, I have switched over to using white calf tail and gray poly-pro instead of Z-lon for the posts. It is a highly visible and durable material for a wing post. Try black posts if the weather would turn sunny.

You can also tie your BWO's comparadun style using dun colored snowshoe rabbit's foot as the wing instead of hackle.