No Miss San Antonio 1931
The Inter-City Beauty Contest (Miss America Pageant) did not exist in 1931.
The International Pageant of Pulchritude held its 6th and final pageant in the United States in 1931, however, the pageant was dealing with internal issues. The previous year confused the public due to the fact that two International Pageants were held; one in the United States and the other in Brazil.
It is possible that the internal issues with the pageant caused San Antonio to lose interest in the event. There is no record of any Miss San Antonio 1931.