Fig.21   Apterae on Chrysothamnus; (a) R IV+V of Pleotrichophorus pycnorhysus, (b) R IV+V of P. gregarius, (c) Dorsal abdominal hairs of P. magnautensus, (d) Same for P. utensis, (e) Spinal abdominal tubercles and hairs of P. gregarius, (f) Dorsal cephalic hairs of P. elongatus, (g) Same for P. packi, (h) Dorsal abdominal hairs and spicules of P. oestlundi, (i) SIPH and dorsal abdominal hairs of Durocapillata utahensis, (j) R IV+V of Aphis chrysothamni, (k) R IV+V of Aphis chrysothamnicola, (l) CAUDA of Aphis ornata.