The spread of the alfalfa weevil through the medium of alfalfa hay and meal has been studied throughout a period of thirteen months. The conclusion is drawn that the large number of weevils present in the growing crop diminishes with each step in the handling of the hay so that the accumulation on the premises of an alfalfa meal mill, even at the end of the summer, is negligible, and the only source of contamination in the mills, generally speaking, is the hay which is being ground. In certain mills whose product was accepted by quarantine officers for interstate shipment, it was possible for weevils to pass through the machine alive, but this condition was easily remedied, so that meal could be delivered uninfested at the door of the freight car. Cars which have been used for infested alfalfa hay, however, remain infested for an indefinite time thereafter and are used more frequently for other commodities than for alfalfa meal. These cars move rapidly and in large numbers into every part of the United States and it is they, and not the alfalfa meal, which constitute the real danger.