Aphid Food Plant Catalogue. 207 



My attention was first directed to this species by a collec- 

 tion made by Mr. George L. Blodget from golden ragwort 

 (Senecio aureus L.) July 3, 191 8. This material was mixed 

 with Macrosiphum solanifolii from which it was easily sepa- 

 rated by its black antenna and cornicle. A second search in the 

 same locality revealed the fact that both these species were also 

 present on the numerous wild roses on the bank of the Penob- 

 scot very near the ragwort. 



Of course the next step was obvious and preparations were 

 made for transfer tests from wild rose to ragwort. The potted 

 plants of ragwort were slow in getting a start and only the 

 rosettes of basal leaves remained fresh for the duration of the 

 test. 



By July 24, these plants seemed in safe condition to use 

 and on that date two viviparous females of the pink color vari- 

 ety were removed from wild rose and caged on the ragwort. 

 One. was apterous and the other alate, and both were somewhat 

 restless during the first day, a condition accounted for, perhaps, 

 by the fact that the new food plant was making less succulent 

 growth than the rose they had been feeding upon. 



July 26, both aphids were feeding head down and both 

 producing young. Ten nymphs present and all were feeding. 



August 2, both aphids were still feeding and producing 

 young, 30 nymphs being present. Their manner was to colonize 

 one leaf and then move to freshly growing uninfested leaf or 

 to a separate plant. The apterous female was removed to avoid 

 overstocking the caged ragwort. 



August 9, several apterous viviparous females matured and 

 were removed. 



August 13, several more mature apterous viviparous fe- 

 males were removed. 



September 12, the first alate viviparous female and several 

 mature apterous ones were removed and, due to the condition 

 of caged plant, the test was discontinued. 



The point at issue, however, has been established. Cap- 

 tives of Macrosiphum pseudorosae were capable of living upon 

 ragwort and their progeny matured upon the secondary host 

 plant. There seems no reason to question the conclusion that 

 the ragwort material first taken in July had had its origin in 

 migrants from the rose as was the case with Macrosiphum solan- 



