96 



ARTHROPODA 



The females bring forth living young at the rate of from 

 three to ten daily for nearly a fortnight and sometimes 

 longer. In two weeks after birth the young generations 

 are sufficiently mature to become the mothers of several 

 daughters daily. Later in the season some of these develop 

 wings, and at the approach of cold weather males are born, 



FIG. 104. Plant lice. Those on the left are enlarged twice, tho; 

 sucking juice are natural size. Photographs. 



at ihe right 



some of which also have wings. In October and Novem- 

 ber, the female deposits numerous fertile eggs which re- 

 main over winter and hatch into stem mothers the 

 following season. So rapidly do the plant lice breed that 

 were it not for their natural enemies, the birds, minute 

 parasitic flies, syrphus flies, and lady bugs, they would 

 destroy most of the vegetation. 



