Fifth Harmony's Lauren Jauregui Misses Brazil Show After Pot Bust

And then there were 4 -- Fifth Harmony went on in Brazil without Lauren Jauregui ... who was clearly grounded after her marijuana bust at Dulles Airport.

The group performed Wednesday night at the Fun Pop Fun Festival in Sao Paulo, proving that old adage about the show going on ... even in Lauren's absence.

We broke the story ... she got popped Tuesday night at TSA. She was trying to board a flight for the Brazil concert. She was cited for possession and released, but not in time to make the show, obviously.

Lauren's attorney says she'll be rejoining the ladies for all future performances.