12 



FARMERS BULLETIN 804. 



The green apple aphis is uniformly green, with black legs, feelers, 

 and hone}^ tubes. Occasionally forms are met which are yellowish, 

 instead of a distinct green. The winged forms (fig. 6, h) haye a black 

 head and body and a uniformly green abdomen. The males and egg- 

 laying females, which are met during the fall, are somewhat smaller 

 and different in color from the agamic forms (fig. 6, c) which occur 



throughout the summer. 



The males are orange yel- 

 low, sometimes with a 

 brownish tinge, and the fe- 

 males dark green. 



SEASONAL HISTOEY. 



are yellowish green, later 

 turning to polished black. 

 They are laid in the fall 

 upon the smooth twigs and 

 water sprouts of the apple 

 (fig. 6, d, fig. 8), and seem 

 to be laid rarely on the 

 trunks and larger limbs. 

 A yery small percentage of 

 the eggs of this species, 

 sometimes as low as 2 per 

 cent, hatches. Hatching oc- 

 curs at about the same date 

 in the spring as in the case 

 of the rosy aphis. 



The yoimg stem-mothers 

 mature in about 10 days, 

 and in about 21 hours after 

 becoming adult begin to 

 produce liying young, re- 

 about two weeks. Between 10 and 50 liv- 



FiG. 7. — The green apple aphis : Curled condition of 

 apple foliage due to this insect. (Original.) 



production continuing for 

 ing 3'oung are produced by each stem-mother, at the ayerage rate of 

 1 a day, although many more may be born daily. Of these young, 

 some deyelop into winged forms, or migrants (fig. G, e,h), and some 

 remain wingless (fig. G, c). They mature in a little oyer a week, and 

 in turn produce either winged or wingless forms. Occasionally 

 another form, intermediate between the winged and the wingless 

 forms, is met. This reproduction continues throughout the summer, 

 from 9 to 17 summer generations occurring before the sexual forms 



