The object of this little booklet is to give a detailed, easily understood definition of the dry fly in compact form as a handy guide, to describe exclusively how the art may be practiced with dry flies copied from native insects. The strictly consistent rule laid down by dry fly experts is, whatever dry fly is used, it must exactly imitate the species of insect that trout The object of this little booklet is to give a detailed, easily understood definition of the dry fly in compact form as a handy guide, to describe exclusively how the art may be practiced with dry flies copied from native insects. The strictly consistent rule laid down by dry fly experts is, whatever dry fly is used, it must exactly imitate the species of insect that trout are then taking as food, or at least the insects visible at the time on the water.