The pigeon fly, Pseudolynchia maura Bigot, has become an important pest of pigeons in many parts of the United States, especially in the South. Haemoproteus columbae Celli and San Felice, the organism of pigeon malaria, which is transmitted by the pigeon fly, was found in the vicinity of Washington, D. C. Preliminary information on the life history and habits of the insect and methods of combating it are given. Thorough cleaning of the pigeon nests at intervals not to exceed twenty-five days is advocated in order to destroy the pupae before the flies have had time to emerge. Dusting the squabs and pigeons with fresh pyrethrum powder, Derris powder, or tobacco powder containing about 6 per cent nicotine kills a large percentage of the insects. An aqueous extract of pyrethrum with soap, used as a dip, is effective as is also Derris extract, soap, and water. Kerosene extract of pyrethrum, used as a light spray, kills the flies in buildings or on the birds.