WALNUT APHIDES IN CALIFORNIA. 



size; subcosta and wing insertions pale yellow; stigma pale gray, with, a darker area 

 at the confluence of the third discoidal vein, and another such though smaller area at 

 the apex; veins rather heavy, dark brown, all three discoidals arising from the sub- 

 costa and thickened at their bases; second branch of third discoidal nearer the wing 

 apex than the first fork; third discoidal describing a regular gentle curve for its entire 

 length; stigmatic vein entire, the depth of its curve varying in different examples, 

 generally reaching the wing margin midway between the apex of the stigma and the 

 the end of the third discoidal (often it touches the margin considerably nearer the 

 stigma, but rarely nearer the third discoidal) . Legs rather short, but a little longer than 

 those of the pupa; front pair yellow with the tarsi and apical third of the tibiae dusky 



Fig. 5. 



- Chromaphis juglandicola: Winged viviparous female (appendages of left side removed). 

 Left antenna; 6, right cornicle; c, front tarsus. (Original.) 



gray and the knee spot rarely present (gray when present) ; middle pair yellow, with 

 an indefinite gray spot on the upper side of the femur above the knee and with the 

 tarsi dusky gray; hind pair yellow, with a coal-black spot (sometimes produced into 

 an annulation) on the upper side of the femur above the knee joint and with the tarsi 

 dusky gray as in the other pairs. The knee spots are always present on the hind 

 femora, while they occur in about 80 per cent of individuals on the middle femora. 

 In 35 individuals examined throughout the year all had the spots on the hind femora, 

 28 had spots on the middle femora, and only 1 had spots on the fore femora. Abdomen 

 pale lemon-yellow, widest at segment 3, considerably wider than the thorax, gen- 

 erally bearing two oval brown spots on segment 5 and more rarely with two similar but 

 smaller spots on segment 4 ; occasionally immaculate . These spots are sometimes gray- 

 ish, varying in intensity, and appear to be the pupal markings retained in-the adult form. 



