A Douglas O-2 variant but not an observation aircraft. The rear cockpit has no gun ring but otherwise it looks like an O-2H. Possibly a clue is the two stars on the fin. Is it a personal transport for a two-star general?
The Douglas O-2 was an O-2H variant used as a communications aircraft and the two stars on the fin does indicate a personal transport for a two-star general. He was Major-General James Fechet. Quite a number of our readers knew of him!

Самолёты на фотографии: Aircrafts on the photo: Douglas O-2 / BT - СШАUSA - 1924