ELM LEAF CURL AND WOOLLY APPLE APHID. 



243 



Fig. 444. Third generation. 

 (From Riley.) 



and 458, cover the ordinary range. The absolute size of this 

 generation is subject to considerable variation. These develop 



within and mi- 

 grate from the 

 elm leaf curl, and 

 settling on apple 

 produce young 

 which inhabit ap- 

 pie. 



Fourth genera- 

 t on. That from 

 the first winged 

 females : Differs 

 from the preced- 

 ing in the pro- 

 m u s c i s being 

 much longer. 



The antennae have 6 joints, with no annulated constrictions. 

 The color is sometimes decidedly orange. When newly hatched, 

 the thickened end of the promuscis often extends one-half the 

 length of the body beyond caudal extremity. It is born with an 

 enveloping pellicle or pseudovum, and though of a bright red 

 with pale legs at first soon becomes brownish, with dark mem- 

 bers. Deposited on apple by the spring migrants and developing 

 there, in flocculent masses. Fig. 448. When mature, if the 

 colony is crowded, some of the individuals move to a new 

 cite on the apple bark before giving birth to the nymphs which 

 settle near and establish thus new colonies. In other cases the 

 nymphs themselves scatter to new cites. 



Fifth generation. The second apterous generation on apple 

 bark. Practically like the fourth generation. 



Sixthl generation. From about the first of September until 

 frost the winged fall migrants develop in the woolly colonies on 

 apple, mountain ash, and Crataegus whence they migrate to elm 

 bark to deposit their progeny, the true sexes. Figs. 455, 456, 

 457 and 459 give the antennae of the fall migrant. 



Together with these in the same woolly colonies develop 

 apterous viviparous females that give birth to nymphs which 

 seek the roots of the trees and hibernate there, surviving the 

 vrinter if the conditions are favorable". 



