THE MONTHLY BULLETIN. 81 



THE WALNUT PLANT LOUSE. 



Ghromaphis juglandicola (Kalt). 

 (Fig. 63.) 



General Appearance.— The presence of this louse is usually mani- 

 fested by the smutting of the walnut trees during the early summer 

 months. ' Close examination, especially of the under sides of the leaves 

 will reveal the minute, light yellow lice. When magnified the winged 

 lice will be found to have black markings on the antenna, the middle 

 and hind femora, and on the abdomen. The true wingless lice have 

 two distinct broad black bands across the bodies. 



Life History. — The sexual forms in the fall deposit eggs upon the 

 branches. These hatch in the spring and give rise to great numbers 

 of young which follow. The growing lice excrete a large amount of 

 honeydew which covers the foliage and ground beneath the tree. This 

 honeydew is responsible for the smutting. Late in July and in August 

 the numbers gradually diminish and when the leaves begin to fall only 

 the freshly laid eggs remain upon the branches. 



Distribution. — Throughout the central and southern parts of the 

 State. 



Host Plant. — So far as known this louse works only upon the cul- 

 tivated walnut. 



Natural Enemies. — The most effective natural foe of this louse is the 

 ashy gray ladybird beetle {Olla abdominalis Say). The work of this 

 beetle is often phenomenal, so much so that in not a few seasons all 

 of the lice disappear by midsummer. 



THE WILD WALNUT LOUSE. 



*Monellia californica Essig. 

 (Fig. 64.) 



General Appearance. — This louse is often confused with the walnut 

 louse {CJiromaphis juglandicola Kalt), which is so troublesome in the 

 walnut orchards of Southern California. The difference in markings 

 easily separates the two lice. All of the adult females appear to be 

 winged, the young n^^mphs being the only apterous individuals 

 observed. The adults are bright yellow in color with antennae, a band 



*Tlie ending of tlie specific name should be "a" instead of "us," as first described. 



6 H 



