"Sec. 2218.    Appointment of lieutenants and substitute lieutenants by councilors and their allowances. — Each councilor shall be empowered to appoint one lieutenant in each barrio under his immediate supervision. A lieutenant of barrio shall be a duly qualified elector, shall receive a reimbursement for traveling and other expenses not to exceed fifteen pesos per month, and shall report directly to the councilor appointing him. Each councilor shall be empowered to appoint a substitute lieutenant who shall be a duly qualified elector, for each barrio under his immediate supervision to take the place of the lieutenant of such barrio, during the temporary absence or inability to perform his duties, and he shall receive the reimbursement which otherwise would be received by the proper barrio lieutenant during the latter's absence from duty: Provided, however, That if on account of the allowance of the barrio lieutenants and their substitute by virtue of this Act, the municipality concerned incurs an overdraft in its general fund or the operating expenses thereof exceed the revenue collection of the municipality, the Mayor, upon the recommendation of the municipal treasurer, shall stop the payment of said reimbursement until such time as available fund exists for the purpose to be certified by the municipal-treasurer: Provided, further, That barrio lieutenants may be employed in national, provincial and municipal public works projects and may receive compensation therefrom, but they shall not receive the corresponding reimbursement for traveling and other expenses herein authorized during the days of such employment."