The crippled emerger transformer (CET) was designed by Bill Anderson to represent multiple stages of the may fly. It imitates the emerging fly and the spinner form. It features a thread body and tails   and a high floating and durable polypropylene wings. It can imitate any mayfly by simply changing colors and sizes.  Pull the wings up and apply floatant for a crippled dun (Wings out body stuck in the shuck). Pull wings out flat and it becomes a spinner. Clip most of wing off, trim the tails back, sink it and it becomes a true emerger.

A video and materials list is below.

Hook – Daiichi 1130 or Tiemco 2487 fine wire scud hook, #14, #16 and #18.

Thread –  3/0 Rusty Brown Uni-thread for hook sizes 14 and larger . 6/0 Uni-thread for hook sizes 16 and smaller.  Used for abdomen and tails as well as for fly construction.

Dubbing – Sulfur Yellow Superfine or equivalent

Wings – Poly Pro Floating Yarn or “Para Post” , Light Grey (for sulfurs).

Instructions for tying Bill’s Sulfur Cripple Emerger 

  1. Pinch Barb and mount hook in vise leaving bend exposed.
  2. Start thread one eye width behind hook eye and build a tight thread body all the way to the vertical on the hook bend. Wrap the thread back on itself as you hold the tag end in your left hand. Leave the tag end for the middle tail.
  3. Make Loop in thread and wrap first over. then under, then over, locking the loop.
  4. Wrap In a spiral to create segments back up to middle of the hook shank. Note the thread loop you formed will become two of the three tails. The third tail is the tag end from when you built the thread body.
  5. Apply dubbing to bobbin thread using dubbing wax. Dub to a point about 1/3 back from the hook eye. (see pic below).
  6. Tie in “Poly wing” with figure 8,  pass thread over and back one time only,  and finish up with thread 1/8” from rear of wing.
  7. Pull wings upright, take two turns in front and two or three turns behind the wings. Pull wings straight back and cut to length approx. the length of the fly body. Get the proportions from pics and from observing the bug,  i.e. go long and take your scissors with you. Note wings should be fairly sparse and transparent, not thick.
  8. Apply a small amount of dubbing to thread and wrap around shank twice in front of the wings do not go thru the wings.
  9. Whip finish head and apply head cement liberally to abdomen, tails, and head. Be careful not to get cement on the dubbing.
  10. Cut the loop and tag end to form three tails with the thread. Tails should be roughly equal in length to the fly body (see pic).
  11. Split the three tails into position with a bodkin while applying more cement. You’ll get some cement on your vise which you can scrape off later. (Or if you are a clean freak like Cliff you can slip a playing card under the tails before applying cement).

Note: This pattern can be adapted for any mayfly which swims to the surface before leaving its nymphal shuck. I have used it successfully for BWO, Hendricksons, Light Cahills, Grey Fox and others.

CET Sulfur


polypropylene yarn that can be bought for our local flyshops