((a)) Whoever establishes any private express for the conveyance of letters or packets, or in any manner causes or provides for the conveyance of the same by regular trips or at stated periods over any post route which is or may be established by law, or from any city, town, or place to any other city, town, or place, between which the mail is regularly carried, shall be fined not more than $500 or imprisoned not more than six months, or both.

((b)) Whoever transmits by private express or other unlawful means, or delivers to any agent thereof, or deposits at any appointed place, for the purpose of being so transmitted any letter or packet, shall be fined under this title.

((c)) This chapter shall not prohibit the conveyance or transmission of letters or packets by private hands without compensation, or by special messenger employed for the particular occasion only. Whenever more than twenty-five such letters or packets are conveyed or transmitted by such special messenger, the requirements of , shall be observed as to each piece.