Vinaya Texts, Part II · 166 of 189
Kullavagga, Third Khandhaka, Chapter 13
13.
1.Now at that time the venerable Udâyi committed an offence—the first Samghâdisesa—and for half a month he concealed it.
[The rest of this chapter is precisely the same as chapter 3, reading ‘for half a month’ instead of ‘for one day.’]