72 THE MONTHLY BULLETIN. 



THE LUPINE APHID. 



Macrosiphum alhifrons Essig. 

 (Fig. 57.) 



General Appearance. — Large green lice, completely covered with 

 fine white powder, which makes them appear silvery-gray; length, 3 

 to 4 mm. 



Life History. — The lice appear in the spring, soon after the lupines 

 are well started, and are especially abundant about flowering time. 

 The younger shoots and especially the flowering tips are attacked 

 and many lice continue to work upon the green seed-pods. The species 

 collects in large colonies and works great havoc upon the hosts. 



Distribution. — In the southern part of the State. 



Food Plants. — ^Wild lupine {Lupinus albifrons). The insect is men- 

 tioned here because of its liability to infest lupines used for cover crops. 



Natural Enemies. — The writer was able to breed out a large internal 

 parasite from this species, which has not been determined. 



THE GREEN CITRUS LOUSE. 



Macrosiphum citrifolii (Ashm.). 

 (Fig. 58.) 



General Appearance. — A large green louse, about the size of and^ 

 greatly resembling the destructive pea louse {Macrosiphum destructor) 

 in color and shape. Under the microscope it will be found that the 

 tips of the cornicles (honey tubes) of the pea louse are perfectly 

 plain, while there are mosaic markings on those of fhe green citrus 

 louse. 



Life History. — The young lice appear on the tender shoots early 

 in April and are especially abundant upon young orange trees in the 

 nursery. Winged and apterous forms continue to appear throughout 

 the entire summer, but only in the spring and early summer is this 

 species a pest. 



Distribution. — Throughout the citrus belt of Southern California. 



Food Plants. — Found especially abundant upon young orange seed- 

 lings and on suckers of large seedling orange trees. It is probable 

 that the older foliage of most of the orange trees is attacked. 



Natural Enemies. — The larvae of the predaceous ladybird beetle 

 {Hippoclamia convergens) feed upon this species in limited numbers. 

 The most efficient predators are the larvse of the green lacewing (Chry- 

 sopa calif arnica) and the large syrphid fly {Lasioplitliicus pyrastri). 

 The internal parasite Charips xanthopsis also works upon this pest. 

 These natural enemies are usually sufficient to hold it in perfect 

 control. 



