334 



Nectar From Plant Lice. 



branches of our willows, which they often entirely cover, 

 and thus greatly damage another tree valuable for both 

 honey and pollen. Were it not that they are seldom numer- 

 ous two years in succession, they would certainly banish 

 from among us one of our most ornamental and valuable 

 honey-producing trees. These are fairly thronged in Sep- 



FlG. 



i V 



FrmaU. Male. 



Sycamore Plant Louse, much enlarged. 



Fig. 142. 



Female. Male, 



Apple Tree Aphis, Clinch ma^jiiyied. 



tember and October, and not unfrequently in spring and 

 summer if the lice are abundant, by bees, wasps, ants, and 

 various two-winged flies, all eager to lap up the oozing 



