UML-actors in the use case

Let's say that i have started making an use case diagram for tourist agency web application. So what bothering me is the thing that i am not sure should i make administrator role and connect him with other actors with the generalization because they share common behaviors.

For example, i have web-site visitor as a role, then i have registered one who can book hotels... Now i was thinking of putting the administrator role who would have permit ions to do what ever he wants to do. So all i need is your advice and what you would do if you will ever have the similar problem.