We tied these using orange 6/0 Danville thread, the body is a mix of equal parts yellow and orange dubbing with a smidgen of brown to mute the bright colors, the rib is doubled and twisted 3/0 brown monocord, and the collar is a brown speckled hen body feather.
(Click on images to enlarge)
This is an easy tie that works well this time of the year, fished any time of the day. We've been known to fish them with a split shot on the tippet to get them down into the deep holes and runs. Fish them through the run and don't lift the fly to cast again until the current has brought the fly to the surface. We get some hard takes on the end of the drift just as the fly ascends to the surface.
Have fun and sharpen your hooks!