Antennal appendage: in Mallophaga, a projecting process of the 1st or 3rd segment in the male.
"Explanation of Terms Used in Entomology" by John. B. Smith
An Alphabetical List of Species of Mallophaga Removed from Birds Collected on the Yucatan Peninsula in 1962.
"Summer Birds From the Yucatan Peninsula" by Erwin E. Klaas