During the movie, the Air Force sends out a message to members of the Ground Observer Corps asking for help in spotting the mantis. This was a real group that existed at least since World War Two. It was comprised of regular citizens who received basic training in spotting and identifying aircraft, but was discontinued in 1958.
Two actors went on to become well-known TV detectives: Craig Stevens became Peter Gunn on Peter Gunn (1958), while William Hopper became Paul Drake on Perry Mason (1957).
Marge reads a newspaper which contains a story with the headline "Mercury New X-ray Source, Two Scientists Report". This same story appears in many movies and TV shows with newspaper close-up scenes. In real life it originally appeared in newspapers in 1934.
In the movie, the prehistoric insect is 200 feet long - twice the wingspan of the C-47. Extrapolating from a 5 gram praying mantis the creature weighs over 705,000 pounds or 320 tons - about the same as a fully loaded Boeing 747.