I call this a Kinder, Gentler Mop Fly because it’s not quite as garish as versions I’ve tied in the past. I think it’s possible that even more traditional tiers would see a good bit of merit in this version because of how well it imitates real cranefly larva, a favorite food source of trout on many rivers and streams.
I begin with a Dai-Riki #135 in size 12. After getting the hook firmly secured in the jaws of my tying vise, I load a bobbin with a spool of 140 Denier dark gray thread. Get your thread started on the hook shank leaving a small space behind the eye and take a few wraps rearward before snipping or breaking off the tag.
The mop tentacle choice is up to you. These mottled gray specimens are from an automotive wash mitt. What I once thought was a lifetime supply is now getting a little low. Get hold of one of the tentacles with the rounded end pointed to the rear of the hook. Gently strip off the outer fuzzy fibers to expose a small portion of the string-like inner core. Place the core on top of the hook shank above your tying thread and then give your bobbin a counterclockwise spin to uncord and flatten the thread. This will also cause it to jump slightly rearward when you make the first wrap so you catch the string core. Continue taking thread wraps to bind the core to the top of the hook shank, making sure that it’s locked down really well. It’s always a good idea to give a little pull on the tentacle to make absolutely certain it won’t pull free.
The head of the fly is created using gray rabbit fur. Take an ample pinch from the packet and set it aside for the moment. Once again, give your bobbin a gentle counterclockwise spin to flatten out the thread. Doing this makes it easier to further flatten the thread with your bodkin and then split it in half to form two roughly equal legs. Insert the tip of your left index finger between the two strands to keep them separated. Then, begin placing small slips of the rabbit fur dubbing up between the two strands. They’ll usually stay in place, even without dubbing wax. Usually three small slips is plenty. Remove your index finger then give your bobbin a clockwise spin which will cord up the thread and trap the rabbit fur to form a nice, bushy dubbing noodle.
Start taking wraps with the noodle, beginning right at the front edge of the mop. Keep making touching wraps forward, preening the fur back as you go. Ideally you want the noodle to end right at the hook eye. Take a few wraps of tying thread behind the eye and then make sure to give your bobbin a good counterclockwise spin to flatten out the thread that you just corded up. Otherwise, when you go to do a whip finish, you’ll likely get a nasty little knot when you pull the loop underneath the thread wraps to tighten it. After completing a 4 or 5 turn whip finish, seat the knot really well and snip or cut your tying thread free. And that’s all there is to it. Flies really don’t get more simple than this.
The long extended body allows for a lot of movement out of the water and, once it gets saturated underwater, it becomes almost jelly-like. To me, it’s remarkable how much this version of the mop resembles real crane fly larva. I mean, c’mon guys, that’s pretty darn close.