Section 184. Prosecutions under the preceding section shall not be commenced until the party concerned is notified and given an opportunity to be heard before the director of standards. No dealer shall be prosecuted thereunder if he establishes a guaranty, signed by the wholesaler, jobber, manufacturer, dealer or other person residing in the United States, from whom he purchased such articles, that they are correctly marked or labelled under section one hundred and eighty-one, designating it, and containing the name and address of such vendor, but in that case such guarantor shall be liable to prosecution and to the penalties provided by section one hundred and eighty-three. If section one hundred and eighty-one has been violated and the guarantor is without the commonwealth, no action shall be brought, but the director of standards shall report the facts to the proper national authorities.