Technical Abstract: The glassy-winged sharpshooter, GWSS, Homalodisca coagulata Say, is the main vector of a bacterial pathogen, Xylella, which is a major threat to agriculture throughout California and the southern United States. This bacterium causes many plant diseases but one of the most severe is Pierce's Disease of grapes where infected vines have a reduce yield, and die. To better understand the dynamics of sharpshooter biology, development and feeding, cDNA libraries were made from actively feeding adult GWSS. Then the proteins being expressed within these tissues were identified using amino acid sequence comparison to previously identified proteins from insects and other arthropods. Identification of proteins actively involved in feeding, digestion, development and cellular functions of GWSS will provide specific targets for the development of methods aimed at disrupting GWSS survival and feeding and ultimately at reducing the acquisition and transmission of Pierce's Disease.