Transmission of the Trypanosomatid Flagellate Phytomonas davidi,a Symbiont of the Euphorbiaceae,by the Hemipteran Bug Pachybrachius bilobata scutellatus1

ABSTRACT. Phytomonas davidi is found in the latex of species of the plant family Euphorbiaceae, including Chamaesyce hirta and C. hyssopifolia, to latitude 32°N in the southeastern United States. The hemipteran Pachybrachius bilobata scutellatus (family Lygaeidae) serves as an agent of transmission from plant to plant. Heavy infections of flagellates in the salivary glands were observed; trypanosomatids were less than one-half the size seen in the plants and in the gut of the bug.