During the spring, summer, and autumn of 1935 and 1936, bi-weekly collections of invertebrates were made in the chicken yards of the Zoological Division Field Station at Beltsville, Maryland, U.S.A. Among a miscellaneous group of insects found near a feed trough on 15 July 1935, was a small beetle, Litargus sp. This insect contained two specimens of a peculiar bristly cysticercoid. In September 1936, five beetles, Alphitophagus bifasciatus, collected in the same chicken yards, each contained from 1 to 8 of these larval cestodes. Additional specimens of what appear to be the same cysticercoid were collected by Dr H. L. Van Volkenberg (1931) (U.S. Nat. Mus. Helm. Coll. Nos. 41673 and 41672) on 10 July 1934 and 4 April 1935, respectively, from Ataenius stercorator at Mayaguez, Puerto Rico. A comparison of both in toto mounts and sections of the specimens from Puerto Rico with those from Maryland showed that the larval cestodes are identical. The name Cysticercus setiferus is proposed for this species.