The size of the bait container in relation to the size of the trap is a very important consideration. It has been found that a small pan or a deep pan of bait set in the center under a trap will catch only a small fraction of the number of flies secured by using larger shallow containers. The best and most convenient pan for baits is a shallow circular tin, such as the cover of a lard bucket. Under range conditions it is advisable to use a more substantial bait pan and preferably one 4 inches deep, so that a greater quantity of bait may be used, thus preventing complete drying out between visits to the trap. Its diameter should be about 4 inches less than that of the base of the trap, thus bringing the edge within 2 inches of the outside edge of the trap. For liquid baits the catch can be increased slightly by placing a piece of sponge or a few chips in the center of the bait pan to provide additional surface upon which the flies may alight.