600 



INSECT PESTS OF FARM, GARDEN AND ORCHARD 



to be found on the twigs during the winter, especially at the 

 crotches and around buds and scars. They hatch just before 

 the leaf buds open and the young aphides become full grown in 

 two or three weeks, all of them being wingless. During the next 

 two or three weeks each of these females will give birth to from 

 50 to 100 young, a few of which develop wings. All of the aphides 



FIG. 453. The apple-aphis; a, young tree partially defoliated by the aphis; 

 d, winter eggs on twig. 



of this second generation are also females, which give birth to 

 live young without the intervention of males, which do not appear 

 until fall. Their young develop in a week or ten days and most 

 of them become winged and migrate to other trees. The develop- 

 ment and reproduction continues in this fashion throughout the 

 summer, both winged and wingless females being found in most 

 colonies, though the size and coloration differ in the various 



