Mezhraiontsy [SEP] inception
November 1913 by three Bolsheviks (Konstantin Yurenev, A. M. Novosyolov and E. M. Adamovich) and one Menshevik, N. M. Yegorov. Yurenev was the informal leader of the organization until May 1917 except for one year between February 1915 and February 1916, which he spent in jail on charges of subversive activities.
The members of the Inter-District Organisation occupied a centrist position between Bolsheviks and Mensheviks.
Organizational history Growth during the war.
At the outbreak of World War I in July-August 1914 (and subsequent change
Mezhraiontsy
The Mezhraiontsy (), usually translated as the "Interdistrictites," were members of a small independent faction of the Russian Social Democratic Labor Party (RSDLP), which existed between 1913 and 1917. Although the formal name of this organization was Russian Social Democratic Labor Party (Internationalists), the names "Mezhraionka" for the organization and "Mezhraiontsy" for its participants were commonly used to indicate the group's intermediate ideological position between the rival Menshevik and Bolshevik wings of the divided RSDLP. 
The Mezhraiontsy merged with