COMPARATIVE ULTRASTRUCTURE OF THE SALIVARY-GLANDS OF 2 PHYTOPATHOGEN VECTORS, THE BEET LEAFHOPPER, CIRCULIFER-TENELLUS (BAKER), AND THE CORN LEAFHOPPER, DALBULUS-MAIDIS DELONG AND WOLCOTT (HOMOPTERA, CICADELLIDAE)

The salivary glands of 2 leafhoppers, Circulifer tenellus and Dalbulus maidis (Homoptera : Cicadellidae) were examined by light and electron microscopy. Centrally located and occupying both the head and thorax, the salivary glands consist of 2 paired parts, the accessory glands a nd the principal glands. In C. tenellus and D. maidis, the accessory g lands are large, multicelled lobes that lie anterior to the principal gland. They join the principal glands near the common salivary duct-gl and junction via a thinner tubular duct. The principal glands of both species consist of large binucleate cells that differ in cytology and arrangement. These cells are easily distinguished by unique staining c haracteristics. Circulifer tenellus salivary gland cells are arranged in 2 lobes, the anterior lobe, made up of 3 concentric rings around th e salivary duct and the posterior lobe, arranged in a loose pyramid ex tending above the foregut. Dalbulus maidis glands are similarly organi zed around the salivary duct. (C) 1997 Elsevier Science Ltd.