598 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



This curling of the foliage is more commonly caused by this 

 species than any other, though the rosy apple-aphis has a similar 

 effect. The aphides secrete the sweet honey-dew very profusely 

 and so attract large numbers of ants, which feed upon it. The 

 ants are always found associated with them, and the presence of 

 numerous ants on a tree is a good indication of aphides. The 

 honey-dew soon covers badly infested foliage and upon it there 



*w XlS 



FIG. 450. The apple-aphis (Aphis pomi DeG.): 1, young stem mother; 

 2, adult stem mother; 3, adult apterous viviparous female; second 

 generation; 4, young female, second generation; 5, winged viviparous 

 female of third generation; 6, pupa of preceding; 7 and 8, apterous 

 male and oviparous female all enlarged as indicated. (After Gillette 

 and Taylor.) 



grows a blackish fungus which gives the leaves a sooty appear- 

 ance, often visible on the twigs after they drop, and a good 

 indication of injury by this species. The full-grown wingless 

 females are about one-twelfth inch long, and shaped as shown 

 in Fig. 450. They are of a bright green color, though occasion- 



