Digestive System Morphology and Salivary Enzymes of the Potato Leafhopper, Empoasca Fabae (Harris)

The digestive tract of the potato leafhopper Empoasca fabae (Harris) was very much like descriptions of the tracts of other Empoasca and closely related Cicadellidae. Major morphological differences: (1) no filter chamber was present in E. fabae, (2) the Malpighian tubules were joined at their distal ends which lie free in the body cavity, (3) and the fourth Malpighian tubule branched from one of the other tubules. The principal salivary gland of E. fabae was composed of four pairs of lobes which varied in histological and cytological detail as well as in their staining reaction with toluidine blue, a metachromatic dye. Each accessory gland was attached at one point to the body wall by a muscle. An invertase (sucrase) and amylase (diastase) were active in salivary gland macerates but were not demonstrated in media fed upon by the leafhoppers. Protease activity was found in whole salivary glands. No lipase was detected in histochemical sections of the salivary glands.