The adults, males and females, of the onion maggot, Hytemyia antiqua Meig. and the seed corn maggot, Hytemyia cilicrura Rond. are attracted in large numbers to sweetened baits containing small amounts (1-2 drops to 5 cc.) of several alcohols, particularly allyl alcohol, iso propyl alcohol, ethyl alcohol and butylic alcohol. Allyl alcohol and iso propyl alcohol were the most attractive. These alcohols mixed with honey and water as a medium were most attractive. Sweetened media, particularly molasses, honey or brown sugar, containing yeasts (made with wet yeast, "Fleischmans Yeast" or dry yeast, "Magic Yeast" or "Yeast Foam") also proved to be highly attractive to both species of flies. The baits containing alcohols lost their attractiveness as soon' as the alcohol evaporated. This usually occurred 24 to 48 hours after they were placed in the fie1el. Baits containing yeasts remained attractive 14 to 21 days or longer provided they were not allowed to become dry'. Sodium arsenite added to baits containing alcohols in amounts as large as K ounce to 1 quart of bait did not bring about a perceptible change in the attractiveness of the bait while this amount of sodium arsenite added to yeast baits apparently killed the yeast organism for there was a marked diminution in the attractiveness of the bait, particularly with yeast baits made from dry yeast. In a number of experiments, where .sodium arsenite was used, at the rate of K ounce to 5 quarts of the bait, especially where wet yeast was employed, the attractiveness of the bait was not materially reduced. Further experiments may show that very small amounts of sodium arsenite (sufficient to kill the flies) may be added to sweetened yeast baits without dimininishing the attractiveness of the bait.