Negative Future Imperatives

Question

In reading through Book VI of Vergil's Aeneid, I came across the following line:

851 tu regere imperio populos, Romane, memento

I believe this is translated as "you, Roman, remember to rule the people with authority", where memento is a future imperative. Evidently, future imperatives are used when the command is given for some point in the future. This got me thinking about the situations in which future imperatives could be used.

It makes sense for affirmative future imperatives to exist, because you could give someone instructions to do something for a later date. However, it seems that negative future imperatives would not really be necessary because you could just avoid giving any order or give a negative present imperative (I figure, chances are, if you don't want someone to do something today, you wouldn't want them to do it tomorrow).

Here are my questions:

1. Do negative future imperatives exist?
2. If so, what are some examples? (preferably from the Classical Latin works, but anything is fine)
3. Would this construction be favoured over using a negative subjunctive or non with a periphrastic?

Answer 1

Negative future imperatives do indeed exist. A great many can be found in the laws of twelve tables. Example:

Hominem mortuum in urbe ne sepelito
Do not bury a dead person in the city

Judging by these examples, the syntax is simply ne + future imperative.

I am not sure if memento should be semantically treated as a future imperative. It is a future imperative by form, yes, but the verb meminisse is irregular and this is the only imperative it has. I do not know to what extent memento(te) has the sense of a future imperative. (I asked a separate question about this.)

I have the impression that the future imperative adds a festive or pompous tone to a command. I would use the future imperative in grandiose orders like "go forth and serve your people" but probably not in mundane orders regarding the future like "bring me an apple tomorrow". My idiosyncrasies are no indication of good classical style, so take this bit with a grain of salt.