Flit

Flit or FLIT is the brand name for an insecticide with the primary active ingredient of permethrin. It is most often used to control adult mosquitos. Spraying it into the air kills adult mosquitos that are present and then by settling onto surfaces it kills mosquitos that may later land. A device called a flit gun was often used to perform the spraying, although today backpack-mounted and aerial sprayers have largely replaced flit guns.

Flit is best known today because in 1928, when Standard Oil Company manufactured it, they promoted it with a very successful and long running advertising campaign. Theodore Seuss Geisel created the artwork for this campaign, years before he started writing the children's books that made him famous as Dr. Seuss. The ads typically contained the tagline "Quick, Henry, the FLIT!" and showed people threatened by whimsical, menacing insect-like creatures that will look familiar to fans of Dr. Seuss's later work. This advertising campaign continued for 17 years and made "Quick, Henry, the FLIT!" into a national catchphrase.