118 NORTH AMERICAN INSECTS. 



fact, tliey are called the milk-cows of the Ants, because 

 the latter suck from them the sweet juice of their 

 honey-tubes. They are as careful of them as we of 

 our cows, protect them from their enemies, and in 

 case of danger, even carry them away in their mouth 

 very carefully to a safe place. This sweet fluid of the 

 Plant-lice is also often seen upon the branches of 

 trees or shrubs, a glutinous substance known by the 

 name of honey-dew, and eagerly sought by Ants. If, 

 therefore, we see Ants running up and down the 

 branches of trees and shrubs, we may consider it a 

 certain indication of the presence of Plant-lice. 

 * There is scarcely a tree, or bush, or herb, that 

 grows in our gardens or fields, that is not infested 

 with some species of Plant-lice. And in spite of their 

 diminutive size, and the disgust we naturally have for 

 them, a host of interesting associations are connected 

 with them. Their manner of living, and of repro- 

 duction also, have attracted much interest. They both 

 deposit their eggs and bring forth their young alive, 

 a phenomenon which does not take place in any of 

 the winged Insects. Their multiplication is immense, 

 and considering the size of the animal, really astonish- 

 ing, for it is a well known fact that one single Plant- 

 louse is capable of producing ninety young ones, from 

 which spring myriads more. From the month of April 

 to November nearly twenty generations are born, and 



