The name deer botfly (also deer nose bot) refers to any species in the genus Cephenemyia, within the family Oestridae. They are large, gray-brown flies, often very accurate mimics of bumblebees. They attack chiefly the nostrils and pharyngeal cavity of members of the deer family. The larva of Cephenemyia auribarbis, infesting the stag, is called a stagworm. The genus name, also spelled Cephenomyia, comes from the Greek kēphēn, drone bee, and myia, fly.
It was reported for many years that Cephenemyia was the fastest of all flying insects, cited by the New York Times and Guinness Book of World Records as traveling at speeds of over 800 miles per hour. The source of this remarkable claim was an article by entomologist Charles H. T. Townsend in the 1927 Journal of the New York Entomological Society, wherein Townsend claimed to have estimated a speed of 400 yards per second while observing Cephenemyia pratti at 12,000 feet in New Mexico.
Using the original report as a basis, Langmuir estimated the deer botfly's true speed at 25 miles per hour.
The latest edition of Encyclopaedia Britannica cites a speed of 80 km (50 miles) per hour for this fly. Time magazine published an article in 1938 "debunking" Townsend's calculations. But the New York Times, which ran a story in 1937 on "the fastest creature that lives', has not yet published a correction.