brown hackle for the tail and a professor for the dropper??? About four o'clock the guide told Walter to rig his rod and they would go in quest of their dinner. Paddling over to a cove where several springs fed the lake they drifted idly while the guide studied the various insects on and above the water. Finally he told Walter to rig two flies, a brown hackle for the tail and a professor for the dropper. The boy had already become fairly proficient in getting his line out cleanly and dropping his flies with that lightness which so closely simulates the falling of the living insects on the water. For "Finally he told Walter to rig two flies, a brown hackle for the tail and a professor for the dropper.", i cannot fully understand the meaning of " brown hackle for the tail and a professor for the dropper." Please kindly help explain it. Thanks.