(a) Subject to the limitations imposed by sections
3204 and
3207 of this title, there may be transmitted as penalty mail
(1) official mail of
(A) officers of the Government of the United States other than Members of Congress;
(B) the Smithsonian Institution;
(C) the Pan American Union;
(D) the Pan American Sanitary Bureau;
(E) the United States Employment Service and the system of employment offices operated by it in conformity with the provisions of sections
49–49c,
49d,
49e–49k of title
29, and all State employment systems which receive funds appropriated under authority of those sections; and
(F) any college officer or other person connected with the extension department of the college as the Secretary of Agriculture may designate to the Postal Service to the extent that the official mail consists of correspondence, bulletins, and reports for the furtherance of the purpose of sections
341–343 and
344–348 of title
7;
(2) mail relating to naturalization to be sent to the Immigration and Naturalization Service by clerks of courts addressed to the Department of Justice or the Immigration and Naturalization Service, or any official thereof;
(3) mail relating to a collection of statistics, survey, or census authorized by title 13 and addressed to the Department of Commerce or a bureau or agency thereof; and
(4) mail of State agriculture experiment stations pursuant to sections
325 and
361f of title
7.
