Mouthpart sensilla in the dragonfly, Brachythemis contaminata (Fabricius) (Anisoptera: Libellulidae)

The mouthpart sensilla in B. contaminata comprise trichoid sensilla, acanthae, basiconic sensilla, campaniform sensilla, microtrichia, papillae, sensory pegs and spines. There are various types of trichoid sensilla: 8 labral, 7 mandibular, 14 hypopharyngeal, 8 maxillary and 17 labial. They differ in size and distribution from one another. The acanthae are of 2 types, the labral in the adult and the mandibular in the larva. The basiconic sensilla are found on the labrum of the adult only. The campaniform sensilla are present on the maxillae and labium of the adult and are lacking in the larva. There are 7 types of microtrichia evident on the labrum, hypopharynx and maxillae of the larva and on the hypopharynx and maxillae of the adult. The papillae are present on the inner surface of the labrum in both the larva and the adult. The sensory pegs are confined to the labium of the adult. The spines are located on the labium of the larva and are lacking in the adult. This study is based on SEM and neuro-anatomical staining techniques.