<p>The antennae and mouthparts of treehoppers in twelve genera (11 Membracidae, and 1 Aetalionidae) were examined to identify and describe the fine structure of the antennae and the mouthparts. The gross morphology of the antennae and mouthparts are similar to that of other previously studied Auchenorrhyncha groups. Six types of sensilla were observed on the setiform antennae: trichodea I (s<i>tr</i>), trichodea III (<i>str III</i>), basiconica I (<i>sb I</i>), basiconica II (<i>sb II</i>), sensilla chaetica (<i>sch</i>) and peg-like sensilla coeloconica (<i>psc</i>). The trichodea and chaetica sensilla were primarily distributed in the scape and pedicel. Peg-like sensilla coeloconica were located only on the flagellum&#xa0;and were found&#xa0;inside cuticular depressions. The antennal scape is characterized by a densely sculptured area. In the labrum, two non-sensory protuberances were identified: acanthae, and scale-like projections. The labium was primarily covered by sensilla trichodea I (s<i>tr</i>) and III <i>(str III)</i>, and sensilla basiconica (<i>sb I</i>) and II <i>(sb II);</i> tooth-like projections were present at the apex of the labium. Mandibular stylets contained small barbs. More taxa and additional ecological information are needed to determine the adaptative value of the structures identified here.</p>