Article CI, Section 2, is hereby amended by deleting the entire section and replacing it with the following:

The Senate shall consist of forty members elected at large in every biennial election following the adoption of this article by proportional representation by all the voters of the Commonwealth.  For this purpose, the Commonwealth may be divided into no more than eight districts from which all or some of the Senators may be chosen; if divided for this purpose, each district shall contain as nearly as possible one-fortieth of the population of the Commonwealth for each Senator chosen therefrom, and no such districts shall be formed by dividing any city or town.  Each Senator shall have been an inhabitant of this Commonwealth five years at least immediately preceding his election, and he shall cease to be a Senator when he ceases to be an inhabitant of the Commonwealth.  The manner of calling and conducting the elections for the choice of Senators, and of ascertaining their election, and of filling any vacancy lthat may occur by death, resignation or removal of any of them, shall be prescribed by law.