We’re kicking off our new Sunday Spotlight series with a focus on Caddis for good reason. First, it's that time of year when caddis are prolific across most rivers and streams in the country. Second, mastering a fly pattern for each stage of the caddis life cycle can lay a strong foundation for improving your on-the-water approach.

This week, I tied up one of my favorites for imitating the final act of the caddis’s journey: Mercer’s Missing Link.

Why Mercer’s Missing Link?

This pattern is one of the most clever and effective dry flies around—especially when trout are targeting cripples or egg-layers. The Missing Link is tied to suggest multiple stages of the caddis’s end-of-life struggle, making it an excellent all-purpose fly during active hatches.

Here’s what makes it work:

The elk hair post and hackle give the impression of a crippled adult caddis struggling to emerge—something that happens surprisingly often (While no definitive studies exist, trout seem to key on crippled caddis or caddis experiencing difficulty emerging enough to suggest a high percentage of these exist in every hatch).
The flash wrapped abdomen of the fly can also imitate an egg-laying caddis, dipping down on the surface film before vanishing in a rise.

And like most things in nature, reproduction is risky business. For the trout, that vulnerability translates into an easy meal. For us, it translates into a highly productive pattern.

Mercer’s Missing Link Materials

Hook: Standard dry fly hook. Here a Hends BL454
Thread: Brown Veevus 16/0
Abdomen: Sulky Holoshimmer thread
Thorax: BWO Superfine dry fly dubbing
Wing: Elk Hair
Hackle: Any color you want, here a brown whiting 100 pack hackle in sz 16
Spent Wings: White EP Fibers

Tying Tips & Variations

This is one of those flies where creativity pays off. You can adjust the flash, body tone, or hackle color to match your local hatch.

There’s no real “wrong” version of the Missing Link. In fact, altering the profile can imitate both a caddis and a mayfly. Drop the wing down and it’s full on caddis, keep it up and it’s more like a sparkle dun. No matter what hatch is on, small adjustments to color and silhouette can make this fly even more dialed-in.

Pro tip: Tie up several at a time. Fish absolutely love this pattern, and you’re likely to go through a few when they’re feeding with confidence.

Final Thoughts

If you’re looking to add a dry fly with versatility, realism, and built-in movement to your box, Mercer’s Missing Link deserves a spot. It’s a killer representation of that vulnerable moment when adult caddis are at their most exposed—and trout know it.