24 John June Davis 



Beak reaching coxae of hind pair of legs. Length of cornicles, 0.28 mm; 

 of style, 0.16 mm. 



This species differs from M. rosarnm as follows : 



M. potentillae Williams. M. rosanim (Kaltenbach). 



Winged. Winged. 



Tuberculate sensoria on III, IV, Tuberculate sensoria on III only, 

 and V. 



Segment VI filament longer Segment VI filament shorter 



than III. than III. 



Cornicles not reaching to tip of Cornicles reaching about to tip 



abdomen. of abdomen. 



Wingless. Wingless. 



Sensoria on antennal segments No sensoria on antenna! segments 



III and IV. Ill or IV. 



Camera liicida drawings of the head, antenna, wing, cornicle 

 and style of winged viviparous female ; and head and antenna 

 of wingless viviparous female, are given on Plates VII and VIII, 

 figs. 117 to 121. 



83. M. ribis (Linnaeus). 



84. M. rosarum (Kaltenbach). 



85. Macrosiphum purpurascens Oesthmd {Myzns thalictri Williams). 



" Myzus thalictri n. sp. No. in. On Thalictrum, Ashland, 

 6/1 1, '90." 



On this slide are three adult wingless females, two of which 

 are viviparous and one oviparous, also four winged individuals, 

 three of which appear to be males and one a viviparous female, 

 and two immature. I consider Williams' thalictri a synonym of 

 M. purpurascens Oestlund. Apparently only antennal segments 

 III and IV bear sensoria according" to Oestlund's synoptic table. 

 However, I have winged specimens from Dr. Edith M. Patch 

 which are labeled " 77-06 Macrosiphum purpurascens Oestl. 

 Meadow-rue, Thalictrum polygomum, Orono, Maine. July 21, 

 1906 . Det. by Oestlund," which bear numerous sensoria on 

 segments III, IV, and V of the antennae, and which agree well 

 with what I consider males on Williams' slide above mentioned. 



Additional notes on the Williams' specimens as follows: 



276 



