mexicana

Man at left appears to be Edgar Gott, then head of Keystone Aircraft:

#5 is Francisco Ignacio Madero, President of Mexico 1911-1913. The caption says "F. I. Madero" and the photo is a match for the one in the Wikipedia article.

#3 in the photograph is Venustiano Carranza. I haven't heard of the Carrenas name in Mexico, unless it could be Carreñas. Yet, when I saw who the person was, no doubt, his beard and eyeglasses says it all... he is Venustiano Carranza. When president Madero (#5 in the photograph) and Pino Suarez are assasinated by Huerta (not in the picture), Venustiano Carranza declares war against Huerta on the inconstitutionality of the coup d'etat. His army was known as the Carrancistas or the Ejercito Constitucionalista (Constitutionalist Army). He also became president but was also assasinated.

tolteca_pilo: Thank you for the additional information! We will edit the source data to reflect that #3 appears to be Venustiano Carranza and then reload the description to Flickr.

After writing my first comment I learned a new fact. According to Taibo, biographer of Pancho Villa, this is one of two similar photographs. Both are the same, only difference is that Pancho Villa appears in one. No one knows why he dissappeared for the second photo.

muy interesante la colección de fotos sobre el moviento de la Revolución Mexicana...! He posteado algunos tags como referencia, exito!

This is the ill-fated Keystone Pathfinder named "American Legion." See: en.wikipedia.org/wiki/Keystone_Pathfinder