The Aphid of Choke Cherry and Grain 295 



Grain Generations. 



Apterous viviparous fe^nale. Unlike their choke cherry pro- 

 genitors, the summer colonies do not share pulverulency in any 

 instar. In general body color they are soft dark green, dull 

 amber greenish, to very pale greenish; always unmarked by any 

 darker green streaks and always with strong 'rusty space at base 

 of cornicles and often connecting them, a color being due to 

 internal structure showing through the body wall. 



Alate viviparous female. The laboratory bred specimens 

 had olive green abdomens with black lateral spots, a black patch 

 at caudal base of cornicle and some black median dashes caudad 

 the cornicles. 



Summer Food Plants. 



Migration tests were made by placing the winged June 

 forms on various grasses. The progency of the migrants accepted 

 the following : Timothy, Kentucky bluegrass, sheep f esque, 

 meadow fesque, red top, barley and oats. The test was continued 

 through one generation only, except with the oats which was 

 used during the summer for the material under observation. 



Life Cycle. 



No data are yet available for the stem female as the first 

 choke cherry collection was made June 25. At this time both 

 apterous and alate viviparous females were present, the latter 

 being recently developed as was evidenced by the abundance of 

 individuals in the pupal instar. 



The migrants were already taking wing on June 25th and 

 the process continued for a week or so longer. 



No collections were taken in the field in the summer here 

 but in the laboratory material continued to live on oats until 

 about the first of September, the colony dying out at that time 

 partly from unknown causes. 



Discussion of Name. 



Whatever the ultimate fate of the name proposed for this 

 species may be, there seems to be no safely established American 



