Hi, FSUMummy. Twotimestalia linked you to a useful document (thanks, sister). In short, traditional chapters meet twice per month while career chapters meet once per month. Both types of chapters are expected to conduct 18 educational programs. "Daytime" and "Nighttime" are not official Beta Sigma Phi terms. Some chapters just choose to designate their meeting times in this way, especially if two chapters exist in the same town.
If you are interested in membership, come visit "The Rosies."
www.geocities.com/umassbeta/rosies.html.
Erica