Notice of lay off and a copy of this clause shall be given to the teacher laid off no later than November 1st for lay off on December 31st, no later than two (2) months prior to the end of a semester for lay off at the end of that semester on or about January 31st, and no later than May 1st for lay off on June 30th. It is understood that lay offs will occur only on the aforementioned dates.