1. The stalk borer, Papaipema. nebris (Gn.), is a native American insect, normally feeding upon Ambrosia trifida but occasionally causing considerable damage to corn and other crops.

2. There is but one generation each year. The overwintering eggs hatch during late April or early May and after a growing period of from 9 to 18 weeks the larvae pupate. The moths emerge during August or September and begin at once to deposit eggs for the next year's brood upon the leaves of grass and weeds.

3. The number of larval instars required to complete development varied from seven to sixteen, average eight, depending upon the kind and quality of the food upon which the larva fed.

4. Natural enemies play an important part in holding this species in check.

5. The important parasites and predators are listed and some notes on their bionomics are given.

6. The elimination of the natural host plants of the borer from the fence row flora and the burning of infested fence rows and grasslands between Nov. 1 and May 1 are recommended as a means of control.