This classic bucktail streamer was first tied by Quebec fly tier Charles Langevin sometime in the 19th century. It was first known as the Langevin but later changed to the Assassin. The assassin was popularized by outdoor writer John Alden Knight. The name “Mickey Finn” arose and was popularized by fellow Canadian writer Greg Clark in the 30s or 40s, who after seeing how effective it was during a fishing trip with Knight, that the fly was as dangerous as a Mickey Finn, referencing the drugged drink. The name stuck and became popular.
The renaming of the fly as a Mickey Finn by Greg Clark stuck as John Alden Knight continued to popularize the fly in his writings of the 30s/40s. The fly has proved particularly effective on BC’s sea run cutthroat trout. [1]
That said, there is some question about the true origin of the fly as claimed by J. H. Brunvand [2] and W. P. Greenwood [3]. The claim is that there is no proof that Langevin created the fly. They also mention that there was in fact a fly named a Langevin as described within Thaddeus Norris’ 1864 book The American Angler’s Book. It however describes a fly made with feathers. They claim the story of Langevin as the creator of the fly story was popularized in 2005 by Canada Post who published it as part of a 4 part stamp set showcasing flies of Canadian origin [4]. The text on their website reads: ” Named after the narcotic-laced drink, the Mickey Finn was another Canadian original, created by Charles Langevin in the 19th century and promoted by John Alden Knight, the inventor of Solunar Tables. It was used on the Jacques-Cartier River in the Quebec City area.”
Recipe:
Hook: 4XL streamer hook
Thread: Black 8/0
Rib: Silver wire
Body: Silver Flat braid or tinsel
Wing: Yellow over red over yellow bucktail (sparse)
Head: Black thread
Type: Bucktail streamer
Originator: Charles Langevin (1789-1869)
[1] https://www.saltwire.com/lifestyles/a-fly-with-a-long-history-190372/?location=pictou-county, May 3rd, 2020.
[2] Brunvand, Jan Harold, “More on the Mickey Finn”, The American Fly Fisher, Vol 41, No 4, Fall 2015.
[3] Greenwood, Willard P. “A Personal and Natural History of the Mickey Finn”, The American Fly Fisher, Vol 40, No 4, Fall 2014.
[4] https://www.canadapost.ca/web/en/blogs/collecting/details.page?article=2005/02/04/fishing_flies&cattype=collecting&cat=stamps, May 8th, 2014.