Wikipedia: Using the original report as a basis, Langmuir estimated the deer botfly’s true speed at a more plausible 25 mph/40kmh. Time magazine published an article in 1938 debunking Townsend’s calculations. To maintain a velocity of 800 miles per hour, the 0.3-gram fly would have had to consume more than 150% of its body weight in food every second; The fly would have produced an audible sonic boom; The supersonic fly would have been invisible to the naked eye; and The impact trauma of such a fly colliding with a human body would resemble that of a gunshot wound.
Holy Moses! Yes, history making—the parting of the ‘bed scree’.