GUERRILLA (erroneously written "guerilla," being the diminutive of the Span. _guerra_, war), a term currently used to denote war carried on by bands in any irregular and unorganized manner. At the Hague Conference of 1899 the position of irregular combatants was one of the subjects dealt with, and the rules there adopted were reaffirmed at the Conference of 1907. They provide that irregular bands in order to enjoy recognition as belligerent forces shall (a) have at their head a person responsible for his subordinates, (b) wear some fixed distinctive badge recognizable at a distance, (c) carry arms openly, and (d) conform in their operations to the laws and customs of war. The rules, however, also provide that in case of invasion the inhabitants of a territory who on the approach of the invading enemy spontaneously take up arms to resist it, shall be regarded as belligerent troops if they carry arms openly and respect the laws and customs of war, although they may not have had time to become organized in accordance with the above provisions. These rules were borrowed almost word for word from the project drawn up at the Brussels international conference of 1874, which, though never ratified, was practically incorporated in the army regulations issued by the Russian government in connexion with the war of 1877-78. (T. Ba.) GUERRINI, OLINDO (1845- ), Italian poet, was born at Sant' Alberto, Ravenna, and after studying law took to a life of letters, becoming eventually librarian at Bologna University. In 1877 he published _Postuma_, a volume of _canzoniere_, under the name of Lorenzo Stechetti, following this with _Polemica_ (1878), _Canti popolari romagnoli_ (1880) and other poetical works, and becoming known as the leader of the "verist" school among Italian lyrical writers.