ULTRASTRUCTURE OF THE UNIPOROUS SENSILLA ON THE GALEA OF LARVAL MAMESTRA-CONFIGURATA (WALKER) (LEPIDOPTERA, NOCTUIDAE)

The structure and innervation of sensilla on the galea of fifth-instar Bertha armyworms, Mamestra configurata, were examined using bright-fi eld light, scanning electron, and transmission electron microscopy. Fo ur sensillar types were identified. The galea bears two uniporous styl oconic sensilla, one aporous spire-shaped basiconic sensillum, two apo rous basiconic sensilla, and one campaniform sensillum. The uniporous styloconic sensillum consists of a small socketed peg inserted into a large cone or style. Each styloconic sensillum is innervated by five b ipolar neurons and associated with three sheath cells. Four distal den drites end in the peg at various levels beneath the pore and the fifth ends in a tubular body at the base of the peg. The intermediate and o uter sheath cells enclose a very large liquor-filled sensillar sinus. The inner sheath cell forms a nonlapped cylindrical sleeve around the neurons. These sensilla exhibit features of contact chemosensilla.