Vol.1] 



Essig. — Aphididae of California 



325 



Chromapliis juglandicola (Kalt.). The common small yellow 

 aphid occurring in great numbers on the undersides of the leaves 

 of the cultivated English walnut, Juglans regia Linn. It is 

 abundant throughout the state where this tree is grown and often 







,.^1 



Fig. 14. Pterocomma jloccidosa (W'eetl). Three apterous viviparous 

 females almost hid by the white flocculenee. On arroyo willow, Salix 

 lasiolepis Benth. Berkeley, Cal., June 15, 1916. (Original.) 



causes much smutting of the foliage. So far I have never taken 

 it from any other species of the walnut''. 



Thomasia salicicola Essig. A very dark species with a median 

 dorsal longitudinal line on the backs of the apterous females 



a A common yellow species occurring on the leaves of various black 

 walnuts in this region does not seem to agree with the descriptions of 

 CaUipfents rttri/ae (Monell) or MonelUa raryelln (Fitch), however it has 

 been determined as the latter by A. C. Baker. 



