Federal Rule of Civil Procedure 38
Rule 38. Right to a Jury Trial; Demand
(a) Right Preserved. The right of trial by jury as declared by the Seventh Amendment to the Constitution—or as provided by a federal statute—is preserved to the parties inviolate.
(b) Demand. On any issue triable of right by a jury, a party may demand a jury trial by:
(1) serving the other parties with a written demand—which may be included in a pleading—no later than 14 days after the last pleading directed to the issue is served; and
(2) filing the demand in accordance with Rule 5(d).