Trivia: None of the moths seen in the film are actual Death Head moths. In the interest of avoiding the hassle involved with actually shipping moth eggs over, then halting filming so they could be raised to the proper level of maturity, the production crew simply went with a similar looking domestic breed of moth, and glued false fingernails painted with the trademark skull like visage onto their bodies.
Trivia: The female dead body in the funeral home was a real actress, not a mannequin. Because the bug cocoon would be placed in her mouth until it is taken out in the middle of the examination, the prop master made the bug cocoon out of a mixture of tootsie rolls and gummie bears. This way if she accidentally swallowed it, it wouldn't do her any harm.
Trivia: FBI agent John Douglas made Scott Glenn (the actor who plays Jack Crawford) cry, when Glenn was at the Behavioral Sciences Unit (now called Investigative Support Unit) in Quantico, Virginia. He played a tape (sound, not video) of killers Lawrence Bittaker and Roy Norris torturing, raping and killing young girls (between 13-18 years old) in the back of their van. Before the encounter, Glenn was firmly against capital punishment.
Trivia: During the film's production, while Anthony Hopkins was playing Hannibal Lecter, Brian Cox (who played the character in "Manhunter") was playing King Lear at the National Theater. Ironically, during the production of "Manhunter" five years earlier, Hopkins was playing King Lear at the same theater.