Scanning electron micrographs of adult S. dux . A: Sponging mouthpart showing everted labella lobes and numerous sensilla trichodea. Prestomal teeth are bifurcation at the tips. B: Palpus showing strong and long sensilla chaetica (arrow). C: Surface of palpus with amount of sensilla basiconica. D: Higher magnification of sensilla basiconica at palpus with perforation surface.