The members of each of the commissions thus created shall be appointed by the governor from among resident citizens of this state and shall hold the office to which appointed from the date of such appointment until the appointment and qualification of a successor. Vacancies in any of such offices shall likewise be filled by the governor. Each member shall qualify by taking the constitutional oath of office. The members of such commissions shall serve without compensation. Actual and necessary traveling expenses and other expenses necessarily incurred by members while on the business of their respective commissions shall be paid from the appropriations for the expenses of the respective commissions upon proper voucher therefor, signed by the chairman of the proper commission.