I just came across an Article on the "Age determination of the glassy-winged sharpshooter, Homalodisca vitripennis, using wing pigmentation" (C. Timmons et al. J. Insect Sci., 11, 78, 2011). I am citing from the abstract "(The red and brown) pigments are believed to be pheomelanin and eumelanin, respectively. The age of H. vitripennis can be determined by calculating the amount of red pigment found in the wings (...)". And this link states that the final immature stage has red pigments that darken over the sharpshooter's lifespan and eventually become brown/dark. Cool stuff.