Some call it the carburetor boot, some call it the intake manifold. I think it's called the carburetor joint on parts catalogues. You could seal it temporarily until you buy a new one.
I had temporarily repaired mine when it cracked with some electrical tape, and it seemed to hold pretty good for a couple weeks. Maybe a combination of some sealant in and around the crack, and then electrical tape tightly wrapped around the neck would seal it up and hold it sturdy enough to keep it from cracking any worse.