Sec. 2-a. The salary and expenses provided for in Section 2 of this Act shall be paid monthly upon the order of the County School Trustees of such counties out of the county's available and State per capita apportionment coming to such counties; providing that the month of September shall not be paid until the County Superintendent of Public Instruction shall have presented a receipt or a certificate from the State Superintendent of Public Instruction showing that he has made all of the reports required by him.