INSECTS 



males and females are unknown. In the warmer regions 

 of the West Coast of the United States, species that regu- 

 larly produce males and females every fall in the East 

 continue without a reversion to the sexual forms. 



Of the other two species of apple aphids that infest 



the buds in the spring, one is 

 known as the rosy apple aphis 

 (Fig. 95 C). The name comes 

 from the fact that the early 

 summer individuals of this 

 species have a waxy pink tint 

 more or less spread over the 

 ground color of green (Plate 3), 

 though many of the adult 

 stem mothers (Fig. 98 B) are 

 of a deep purplish color. The 

 early generations of the rosy 

 aphis infest the leaves (Fig. 

 98 A, Plate 3 A) and the young 

 fruit (Fig. 98 C, Plate 3 A), 

 causing the former to curl up 

 in tightly rolled spirals, and the 

 latter to become dwarfed and 

 distorted in form. 



The stem mothers ot the 

 rosy aphis give birth partheno- 

 genetically to a second gen- 

 eration of females which are 

 mostly wingless like their moth- 

 ers; but in the next generation 

 many individuals have wings. 

 Several more generations now 

 rapidly follow, all females; in 

 fact, as with the green aphis, 

 no males are produced till late in the season. The winged 

 forms, however, appear in increasing numbers, and by 

 the first of July almost all the individuals born have wings. 



[168] 



Fig. 98. The rosy apple 

 aphis, Anuraphis roscus 3 on 



apple 

 A, a cluster of infested and 

 distorted leaves. B, an adult 

 stem mother. C, young apples 

 dwarfed and distorted by the 

 feeding of the aphids 



