A comparative study was made of the structures of the preantennal region of nine species of Damalinia Mjöberg, 1910 (Phthiraptera: Trichodectidae). Variability in the form of the head, ventral carina, pulvinus, mandibles, and labrum was observed by light and scanning electron microscopy. According to previous studies, the form of the head is possibly influenced by the density and texture of the hair of the host. The ventral carina, which may be sharp or blunt, and the pulvinus, a membranous lobe, of these parasite species of different hosts, were studied. Photographs of the mandibles and labrum show a high variability according to species.