Thesis (Ph.D.)--Boston University. / The "wetback" and bracero episodes of 1930-1960 had their origins in the Quota Act of 1921. The Act, as amended, limited immigration to 150,000 annually and established quotas based on the national origins of the population of the United States. It thereby cut off large-scale immigration from Southeastern Europe. The "wetbacks" who gained their name from their surreptitious and successful attempts to ford the Rio Grande and thus slip illegally into the United States, occasioned no serious problems in the 1930's; during the depression years only a few Mexicans crossed the border and sought work in American fields at harvest time. The American involvement in World War II, however, impelled a substantial displacement of American farm workers; the "wetback" traffic accelerated proportionately. The War's end did not check the swelling influx of illegal entrants. The number grew steadily, prior to 1954, until it approximated 1,200,000 annually. Most members of the migratory labor force, remaining in the United States only during the crop-growing season, returned each year to their homeland. Not more than a small percentage attempted to remain permanently north of the border. [TRUNCATED]