Final answer:
The founder of Beta Sigma Phi is Walter W. Ross, which is an international social, service, and cultural organization for women, not directly related to the National Pan-Hellenic Council or its historically Black fraternities and sororities.
Step-by-step explanation:
The founder of Beta Sigma Phi is Walter W. Ross. However, the information provided refers to several historical figures associated with Greek letter organizations but does not directly answer the question about the founder of Beta Sigma Phi, an international social, service, and cultural organization founded for women. This organization is separate from the National Pan-Hellenic Council, which was mentioned and represents historically African American fraternities and sororities. While Beta Sigma Phi is not one of the historic Black sororities like Alpha Kappa Alpha, nor is it part of the 'Divine Nine' detailed in the referenced work by Lawrence Ross, understanding the context of Greek letter organizations in general, like those mentioned, can be important for appreciating the wide variety of such organizations that exist, including Beta Sigma Phi.