Mailable Live Animals
One important restriction on mailing is that you CANNOT mail fertile ants through USPS.  Which means that all of those ant farms you see being sold to kids?  You pay money, and get some sterile workers who are guaranteed to die pretty fast, leaving an unhappy kid.<p>If you want a real ant farm, you need to either collect ants locally, or buy ants in person from someone who did themselves.  And you'd better known the rules if you want to cross state lines with your ants.<p>(Source, I have a teenager who loooves ants and knows everything about them.  He now has multiple species of ants that he keeps.)