Below are some miscellaneous observations on the film.
1) Some of the scenes with Lecter in them, and a few of the scenes with Jame Gumb in them, take place at a physically 'low' level with respect to the ground - in specific, underground. For example, Lecter's cell is located in the basement section of the building in which he is locked up; recall that Starling's first three interviews of him take place while he is in this cell (in Baltimore). And, many of the scenes with Gumb in them, show him in the basement of the house he is occupying. What is being suggested is that each man inhabits a metaphorical Hell.
Above left: The area containing Lecter's cell is below ground level, as indicated by the fact that Starling and Dr. Chilton have to descend steps to get to it. Above right: Jame Gumb in the basement of Mrs. Lippman's former residence in Belvedere, Ohio.
2) In the well in Gumb's basement, where his victims are held hostage for a few days prior to skinning, it is evident that the walls of the well have some blotches of dark greenish coloring on them, and reddish marks where a previous victim had attempted to claw her way out (left-hand screencap below). And, when Clarice is moving throughout the basement in Gumb's house in pursuit of him, it is observed that the brick walls of the basement itself have blotches of varying colors on them (right-hand screencap below; click image to enlarge). Thus, there seems to be a symbolic correspondence between the well and the basement. This indicates that Clarice being in the basement, corresponds in some way to Catherine Martin being in the well, implying a correspondence between the two women themselves.
3) See below.
Above left: In the West Virginia autopsy scene, we note that two sections of skin have been removed from the autopsied victim's back (click image to enlarge). Recall that a moth cocoon is found in the victim's mouth. Above right: While this cocoon is being analyzed by the two biologists at the Smithsonian (Roden and Pilcher), when one of the men uses a small, sharp instrument to penetrate the cocoon, to help determine what species of moth it is from, it can be seen that the two cuts which he makes are similar in location and size relative to the cocoon itself, to the locations and sizes of the patterns left on the victim's back by the removed patches of skin, relative to her body.
