The alfalfa weevil destroys a great deal of alfalfa in northern Utah and southern Idaho. It also inhabit southwestern Wyoming and is spreading slowly to new territory in all directions. I may in time infest most of the United States. The adult, a small brown snout-beetle, and th larva, a green wormlike creature, usually escape notice during the first two or three years that they are present in a locality, but as soon as they begin to become numerous enough to do harm they are readily found, and their effect upon the appearance of the fields is conspicuous. Vigorous treatment is then necessary to prevent partial or total destruction of the first and second crops. The purpose of this bulletin is to show how serious the attack is to the farmer, how much territory it embraces and how it spreads, a nd to describe the insect, its work, and the methods which are effective in dealing with it.