Beyonce -- Solidarity With Solange

Beyonce is putting it out there as clearly as she can ... she's a member of one big happy family.

Beyonce and Solange reunited in New Orleans Saturday ... Bey posted a pic of the two embracing on Instagram -- and captioned the date and location to show it was legit.

No sign of Jay Z.

Until 4 hours later ... when she posted the trailer for her upcoming collab with Hova and a ton of celebs called "Run."

They are indeed ... just like us.