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
The Sap (1929 film) The Sap (1929 film) The Sap is a 1929 American comedy film directed by Archie Mayo and written by De Leon Anthony and Robert Lord. It is based on the 1924 play "The Sap" by William A. Grew. The film stars Edward Everett Horton, Alan Hale Sr., Patsy Ruth Miller, Russell Simpson, Jerry Mandy and Edna Murphy. The film was released by Warner Bros. on November 9, 1929. The sap, unemployed and hapless Bill Small, is not regarded by his wife Betty and her relatives. But he is redeemed by a wise stock investment in wheat which reverses his fortunes