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Fly Tying: Peeking Caddis

Fountains of Youth – Classic trout flies that have withstood the test of time … flies that remain “forever young”

by Rusty Dunn

‘Stoneflies’ are named for the stony-bottomed, well-oxygenated streams that the insects inhabit.  ‘May­flies’ for the month of May, during which hatches of histori­cally famous English species reach their peak.  But what of ‘caddisflies’?  How were they named?  To­day’s term ‘caddis’ originated in the middle ages from the root word ‘cod’, which is a husk, bag, or pouch.  Larvae of many caddisfly species live within such cods, known today as ‘cases’. 

Dame Juliana Berners recommended use of cased caddis larvae as live bait when she wrote in 1496 “put on thyn hoke a cod­worme” in A Treatyse of Fishing with an Angle.  ‘Cod’ and ‘cad’ were often used inter­changeably in Middle English, and by the 1600s, common names for cased caddis were various permutations of both words, in­cluding ‘cad bait’ (1620, Secrets of An­gling), ‘cados worme’ (1634, Theatrum Insectorum), ‘Cadis-worme’ (The Com­pleat Gentleman, 1622), and ‘cadice’ (The Art of An­gling, 1651).  The modern spelling ‘cad­dis’ ap­peared as early as 1653 in the first edition of The Compleat Angler by Isaac Walton, whose entomologi­cal naiveté was evi­dent when he wrote that a trout “especially loves the May­flie, which is bred of the Cod-worm or Caddis“.

Caddisflies inhabit all trout water and are espe­cially important in streams whose water quality is com­pro­mised.  When water quality declines, the num­ber of aquatic in­sects declines similarly.  Stoneflies are the first to dwindle in number, followed by mayflies.  As the food base shrinks, so does the sustainable popu­lation of trout.  The good news is that cad­disflies are a hardy lot, per­sist­ing in the face of most human in­sults. You’ll find vary­ing num­bers of stone­flies and mayflies during your trouty trav­els, but caddisflies will al­ways be there.  A well-stocked box of cad­dis patterns is per­haps your best angling com­panion.

Most caddisfly species build cases of sand, gravel, or
foraged vegetation glued together with a sticky se­creted silk.  Larvae live within such protective cases, which are attached to rocks or wood on the stream bottom.  Many caddis species carry their cases like travel trailers as they forage and move about the bot­tom.  Trout feed on cased caddis by pluck­ing cases from rocks or taking them adrift in the current.  A few cased cad­dis probably drift throughout the day, but greater num­bers are available during times of behav­ioral drift.  Like many aquatic insects, cased caddis exhibit a daily behav­ioral drift, during which oc­cupied cases de­tach from the bottom at re­produci­ble times and drift downstream be­fore reattach­ing.  Behav­ioral drifts of most aquatic in­sects peak at dawn and dusk, but those of several im­portant cased cad­dis species occur in mid-day.  Trout feed readily on drift­ing cases, es­pe­cially when little else is hatching.

Many generic nymphs are reasonable imitations of cased caddis, but the Strawman nymph, designed by Detroit’s Paul Young, was the first explicit imitation of the group.  Young, who is most famous for his delight­ful hand-made split-bam­boo fly rods, offered Straw­man nymphs in his tackle catalog as early as 1927.  The pattern was later published in his 1934 book Making and Using the Dry Fly.

Today’s most popular cased caddis pattern is prob­a­bly that of George Anderson, owner of a well-known fly shop in Livingston, MT.  He designed the ‘Peeking Cad­dis’ in the 1970s to imitate Mother’s Day cad­dis of the Yellowstone River.  Quoting Ander­son, “The key to tying an effective (cased caddis) imi­tation lies not only in imitating the case but in convinc­ing the trout that it actually con­tains life“.  His pattern imitates a cad­dis larva protrud­ing from the open end of its chim­ney-like case.  A band of brightly colored dubbing imi­tates the abdomen, and a collar of ostrich herl imi­tates the pro­truding thorax and head.  The fly catches trout wher­ever they are found.  If you’ve ever been puzzled by the seemingly inexplicable effectiveness of John Bethke’s Pink Squir­rel, look no further than George An­der­son’s Peek­ing Caddis for inspiration and guid­ance.

Copyright 2017, Rusty Dunn

Peeking Caddis


Hook: 2X-long nymph hook; #10 – #16
Weight: An underbody of lead or non-toxic wire.
Thread: Black, 6/0 or 8/0
Rib: Oval or flat gold tinsel.
Body: Natural hare’s mask fur, tapered slightly.
Thorax: A band of cream or bright green fur dubbing.
Legs: Brown partridge feather barbs, tied either as a collar (Anderson original) or a beard (most popular today).
Head: Black ostrich herl.