62 



THE MONTHLY BULLETIN. 



Fig. 12. The Oat Aphis, Aphis avenw which feeds on apples during the early spring, 



migrating later to oats. 



early in the season, and which has the oat plant for its summer host ; 

 the rosy aphis. Aphis sorbi, which is very destructive to both fruit and 

 foliage and which, according to Professor P. J. Parrott, has the habit 

 of going to the plantain for a summer host;* the clover aphis. Aphis 

 bakeri, which hatches on the apple and thorn twigs in the spring and 



Fig. 13. The rosy apple aphis, Aphis sorbi. Winged and apterous 

 females on an apple leaf. This species attacks apples in the spring 

 and migrates later to other host plants. (After Essig. Injurious 

 and Beneficial Insects of Cal. ) 



in the second and third generations goes to the clovers, especially the 

 red clovers, where it thrives during the remainder of the year; the 

 powdery plum and prune louse, Hyalopterus arundinis, which loads 

 the underside of the leaves of these trees during the early part of the 

 summer and then deserts the trees and goes to coarse grasses, especially 



*In Colorado we have successfully transferred this louse from the apple to the 

 plantain upon which it seems perfectly at home. 



