The New Student's Reference Work/Army-Worm

Army-Worm, the larva of a very common destructive moth. It appears every year in the United States east of the Rocky Mountains, but attracts attention only when it appears in great numbers. Then it marches, like an army, from one field to another, destroying the crops in its path. The worm is one and one-half inches long when full grown, and striped with black, yellow and green. Fields of grain are protected by surrounding them with ditches with vertical sides, into which the worms fall and cannot get out. Their numbers are largely kept down by fungous diseases and parasitic insects.