Hemiptera plant. Phloem sap, which has a higher concentration of sugars and nitrogen, is under positive pressure unlike the more dilute xylem sap. Most of the Sternorrhyncha and a number of Auchenorrhynchan groups feed on phloem. Phloem feeding is common in the Fulgoromorpha, most Cicadellidae and in the Heteroptera. The Typhlocybine Cicadellids specialize in feeding on non-vascular mesophyll tissue of leaves, which is more nutritious than the leaf epidermis. Most Heteroptera also feed on mesophyll tissue where they are more likely to encounter defensive secondary plant metabolites which often leads to the evolution of host specificity. Obligate xylem feeding is a
Sugary drink tax a sugary drink tax alone. In March 2017, Pepsi laid off between 80 and 100 employees at two distribution plants in Philadelphia and one plant in nearby Wilmington, Delaware. The company blamed the layoffs on the tax, an assertion rejected by the city government. In September 2016, the American Beverage Association, Philadelphia business owners, and other plaintiffs filed a lawsuit against the soda tax, alleging that the tax violated the "Tax Uniformity Clause" of the state constitution. The legal challenge was dismissed by the Court of Common Pleas in December 2016, and in June 2017 the Commonwealth Court of Pennsylvania