In Jonathan Demme's new thriller, The Silence of the Lambs the theme of metamorphosis is in part represented by the life cycle of the moth. In a particularly unappetizing autopsy scene, Dr. Akin (Kenneth Utt), assisted by FBI agent Clarice Starling (Jodie Foster) works his forceps into the mouth of a corpse and pulls out a cocoon. According to moth wrangler and special effects wiz Raymond Mendez, ''We made a copy of a real sphinx moth pupa using a rubber mold. Then I poured melted Tootsie Rolls into the mold to form the pupa. We wanted to have something edible in the actor's mouth, not something plastic.'' In a later scene, the offending cocoon was dissected ''using a plastic model, tubing, and K-Y Jelly.'' And for a scene in which Foster enters the killer's den and sights one of the winged creatures, a dull-looking tomato hornworm moth was outfitted in a little harness with colorful trappings made of acrylic polymer and silk. Maybe Silence will get an Oscar for Best Costumes for Nocturnal Insects.