This is an aspect of ZTA's history that I really find interesting. According to
The History of Zeta Tau Alpha, Beta Sigma Omicron was "absorbed" into Zeta Tau Alpha and seven of its chapters became Links in the Zeta Chain. "In the end we have agreed to affiliate only certain of their chapters and have selected only those that will be advantageous to Zeta Tau Alpha." The seven chapters that were installed were: Millsaps College (Delta Phi chapter), William Jewel College (Delta Chi chapter), Howard College (Delta Psi chapter), Westmister College (Delta Omega chapter), Thiel College (Zeta Beta chapter), Evansville College (Zeta Alpha chapter), and Youngstown University (Zeta Gamma chapter).
I have repeatedly tried searching the internet for any information or history about Beta Sigma Omicron, but unfortunately I have not been able to find any.
