Ditto what Bonnie said.
Or put stuff in the freezer when you first bring it home and leave it there for seven days. That will kill them.
They're called granary weevils and can be found in seeds, grains, rice, cereals, breads (in your case, bread crumbs, Jen), and baking products. If you're absolutely certain that your bread crumbs were sealed, you shouldn't have anything else to worry about. However, if the crumbs were already opened for a while, there are chance that other stuff in the pantry might be infected and you'll have to throw that out.
Here's the good news -- they are simply a grain pest. They don't spread diseases, bite, or sting. They won't poison you and can't make you sick. Chances are, you've consumed a handful or so of the small larvae in your lifetime. They're more of a nuisance to the grain and seed farmers and sellers than anything else.
