Distributional information is presented for Megaderus bifasciatusDupont, 1836, a rare species of longhorned beetle in the cerambycid tribe Trachyderini. Valid occurrence records from Mexico and Central America are listed, and enigmatic historical records for the southwestern United States are examined to attempt to determine their veracity. An inventory of specimens found in museum collections is documented. The records for Texas and Arizona are examined, and the likelihood that the species is, or ever was, present in the United States is discussed.