Missing an air hose that goes from the air breather to ? what is it called?

If its about as big as your little finger in diameter it may be but if its an inch or larger its a manifold heat tube that comes up from the exhaust shroud on the header pipe which is used to preheat air on really cool days.. its usually around a foot long and flexible(bendable) and made from flexhose..parts store sells by the foot if needbe..its like an exhaust patch..they will know when you tell what car it is..(normally)