The two go hand in hand. One is almost essential for the other. Teasing out the difference is sometimes a fool’s errand (appropriate day for that). Digital Literacies are defined in all kinds of ways. The most clearly in Howard Rheingold’s book Net Smart, or Doug Belshaw’s Eight Elements (slide 28 onward, for those who need no context).
But just like literacy is an essential element for the development of a democratic society, digital literacy is essential for quality digital citizenship. One very good resource for a slew of very good tools for defining and developing good digital citizenship from the Northern Gateway school district and recommended by FreeTech4Teachers. Alec Couros has 5 elements of Digital Citizenship that include Identity, copyright, critical thinking, activism and one other I can’t remember.