Cuticular sensory structures on the legs of Orthetrum sabina (Odonata: Libellulidae) as revealed by SEM

Abstract

Occurrence and distribution of various cuticular sensory structures such as Sensilla chaetica, S. trichoidea, S. basiconica, pore sensilla, hairplates, S. campanifonuia, microtrichial structures, as well as unique hemispherical protuberances and flattened branched setae are presented. Their morphology is described, and size ranges recorded.As seen in figures 1 and 2, the coxa has two hairplate like structures, each comprising a group of trichoid sensilla with blunt and slightly bulbous tips. The femur has minute basiconic pegs, and pores as well, scattered on its surface(figure - 3 ). The tibial surface shows a profusion of unique flattened and branched setae (figure - 4 ). Similar setae are also present along the outer margin of the tarsus (figure - 5) which also bears a number of hemispherical protuberances(figure - 6 ).