Cochliomyia americana appeared in Florida early in 1933 and by the end of 1934 had spread into 57 of the 67 counties. Estimates for 1934 indicated an infestation rate in domestic animals in 31 of the more heavily infested counties of about 20% and a death rate of about 6%. More than half of the cases and deaths occurred in hogs; about 1/3 of the cases and 1/6 of the deaths in cattle. Estimated death loss,[long dash]in excess of 50,000 animals during the year. Infestations originated to a large extent in sores caused by ear ticks (principally the Gulf Coast tick, Amblyomma macu-latum), in the navels of new born animals and in wounds following operations and accidental injuries. Screw worm cases, although greatly reduced, continued to occur during the winter. A cooperative educational campaign was conducted by State and Federal agencies to disseminate information on control methods.