The larva of Pilocrocis tripunctata Fab. (fig. 1 c, d), a member of the lepidopterous family Pyralidae, was noted first as an enemy of sweet potatoes in Louisiana by the writer while cooperating with the Louisiana Experiment Stations in the fall of 1914. Since that time the species has been kept under observation at Baton Rouge, La., and has been noted also in Plaquemines and Tangipahoa Parishes. The species, which may be called the "sweet-potato leaf folder" because of the habits of the larva, has not been observed as yet in destructive numbers in Louisiana: but it has been reported by Mr. M. M. High, of the Bureau of Entomology, as very injurious to the sweet potato near Brownsville, Tex., where he conducted control experiments with poisons during the fall of 1916. As it is possible that this pest may become an important enemy of sweet potatoes in the Southern States, it seems advisable to publish the results concerning its biology and the results of Mr. High's control experiments.