81 



them also, causing them to curl somewhat, and this also inter- 

 feres with the proper growth of the tree. In a short time 

 these aphids become full grown and begin to produce living 

 young which feed on the leaves, like their parents. Gener- 

 ation after .generation is quickly produced, and as a dozen or 

 more generations are produced during the summer, and as 

 each adult produces fifty or more young, favorable seasons 

 result in an enormous 

 abundance of these in- 

 sects, all of which are 

 removing from the tree 

 the sap it needs. Thus 

 growth is checked, the 

 apples are stunted, or at 

 least undersized, and the 

 loss to the fruit grower 

 is large. 



When cold weather 

 comes in the fall a change 

 of life takes place. Eggs 

 are laid on the twigs and 

 these hatch the following 

 spring, the aphids on the 

 tree dying. 



The rosy apple aphid 

 has a rather different life. 

 Its eggs are laid on apple 

 twigs in the fall and hatch at about the same time in the 

 spring as those of the green apple aphid. The aphids work 

 on the buds and leaves also, but on the latter much more 

 curling is caused by the feeding than in the case of the other 

 kind. 



After a few generations on the apple in the spring, however, 

 the rosy apple aphids leave the apple trees and go to plantains,, 

 particularly the narrow-leaved plantain, and here they feed 

 and reproduce during the summer. In the fall these insects 

 migrate back to the apple, where as cold weather comes on 

 they lay their eggs. The average number of young produced 

 by an individual of this species is about 175, and the number 



Twig of apple, showing plant lioe. (About 

 natural size.) 



