8 U.S.C. § 1302 : US Code - Section 1302: Registration of aliens

      (a) It shall be the duty of every alien now or hereafter in the
    United States, who (1) is fourteen years of age or older, (2) has
    not been registered and fingerprinted under section 1201(b) of this
    title or section 30 or 31 of the Alien Registration Act, 1940, and
    (3) remains in the United States for thirty days or longer, to
    apply for registration and to be fingerprinted before the
    expiration of such thirty days.
      (b) It shall be the duty of every parent or legal guardian of any
    alien now or hereafter in the United States, who (1) is less than
    fourteen years of age, (2) has not been registered under section
    1201(b) of this title or section 30 or 31 of the Alien Registration
    Act, 1940, and (3) remains in the United States for thirty days or
    longer, to apply for the registration of such alien before the
    expiration of such thirty days. Whenever any alien attains his
    fourteenth birthday in the United States he shall, within thirty
    days thereafter, apply in person for registration and to be
    fingerprinted.
      (c) The Attorney General may, in his discretion and on the basis
    of reciprocity pursuant to such regulations as he may prescribe,
    waive the requirement of fingerprinting specified in subsections
    (a) and (b) of this section in the case of any nonimmigrant.