Ornithocephalus aristatus, a new species from Panama, is described and illustrated. Among the species of the genus Ornithocephalus, it can be distinguished by the nonresupinate flowers, the sepals each provided with a flexuous awn half as long as the sepal itself, the porrect petals with revolute margins, the hastate lip with triangular-ovate, erose lateral lobes, the linear, acute midlobe, conduplicate and subreflexed at apex, and the disc with a bilobed, obreniform callus provided with a conical tuft of stiff hairs. A key to the species of Ornithocephalus from Panama is provided.
