Trout feed on Blue Winged Olive mayflies (BWO&';s) from March to October, the BWO assortment is a curated pack of flies aimed at imitating all the stages of this prolific hatch. With nymphs, emergers, and dries, you&';ll be able to trick picky fish and kept your rod bent. Here&';s what premium hand tied flies are included. Available as a 16pk or a 32pk so that you never run out of a fly that works. 16pk 2x, 32pk 4x BH Blue Wing Olive Nymph #14 & #18 16pk 2x, 32pk 4x Blue Wing Olive Emerger #14 & #18 16pk 2x, 32pk 4x Blue Wing Olive Parachute #14 & #18 16pk 2x, 32pk 4x Blue Wing Olive Spent #14 & #18