INSECTS INJURIOUS TO THE APPLE AND PEAR 



605 



distinguish the species of this genus. The winged female has 

 the head and thorax blackish, and the abdomen yellowish-green 

 or brownish, usually lacking the greenish bands of the wingless 

 form, and the honey-tubes are brown with rusty spots around the 

 base. The species may be distinguished by the very short second 

 fork of the median vein at the tip of the fore-wings. 



Life History. The eggs are found on the apple and pear, and 

 the first two generations in the spring develop as do those of the 



FIG. 458. The European grain-aphis, migrating winged viviparous female 

 of the second generation greatly enlarged. 



preceding species. All of the second, or sometimes the third, 

 generation become winged and migrate to small grains and 

 grasses, on which they feed during the summer. In the fall 

 winged females return to the fruit trees and give birth to young, 

 which develop into wingless females and winged males, which mate 

 and produce the winter eggs. Pergande states that " the species 

 is biennial and that the progeny of the spring migrants from the 

 apple subsist almost exclusively upon various grains and grasses 

 until the fall of the second year, when a generation of return 

 migrants makes its appearance." This is certainly true in the 

 South, where the aphides may be observed on grains throughout 



