The Anato-May Olive is a favorite of ours in sizes 16 and 18 for Baetis nymphs. The Anato-May series of nymphs is a cool collection of patterns from Ken Morrish. We can only assume the name comes from the fact that the patterns are so anatomically correct. They also feature a small bead head that doesn't stray away from the mayfly silhouette and is a neutral black color. Size 16 pictured.