March River/Lake Selection. This is a selection of our favourite patterns based on the natural entomology found on the rivers and lakes during the month of March. This Box contains 2 of each of the following flies. Rough Olive March Brown x 1 and M.B. Spider(#12) X 1 Greenwell's Spider G.R.Hare's Ear (Variant) Pheasant Tail Nymph Partridge and Orange