The two (2) members of the county mosquito control commission who serve by virtue of their office shall serve without compensation. The appointed member of the commission shall serve without compensation except that the necessary expenses for actual attendance of the meetings of the commission and a per diem of Five Dollars ($5.00), not to exceed the sum of Twenty-five Dollars ($25.00) for any one (1) month, shall be allowed and paid by the board of supervisors as provided in this article.