8 John June Davis 



The slide bearing this species was referred to Professor Oest- 

 lund who confirmed Mr. Williams' determination. Drawings of 

 the cornicle of this species and Monell's smithiae are given on 

 ■Plate II, figs. 21 and 22, in order to show the characteristic 

 cornicles of the two species. 



39. Hyalopterus pruni (Fabricius). 

 ■40. Aphis albipes Oestlund. 



41. A. annuae Oestlund. 

 '42. A. apocyni Koch. 



42. A. artemisicola Williams. 



"Aphis artemisicola n. sp. Type No. 53. On Artemisia 

 cana, Squaw Cr., 6/24, 90." 



Several adult wingless and immature but no winged on slide. 

 Antennal segment III of the wingless adult bears 6 to 9 circular 

 sensoria on the basal two thirds. Cornicles imbricated and semi- 

 reticulate at tip. Antennal measurements as follows : 



'Camera Incida drawings of the head, antenna, cornicle and 

 Btyle of wingless viviparous female are on Plate II, figs. 23 to 25. 



Eight species of Aphididae have been described from Artemisia 

 in this country, four of these being described by Mr, Williams. 

 For convenience in comparison I give herewith a table comparing 

 the eight species. All of these species seem to be good and dis- 

 tinct, except possibly A. canae Williams, which appears to be a 

 synonym of A. artemisicola Williams. They may best be con- 

 sidered distinct, however, until proved otherwise. 



The characters enumerated in the following table are for the 

 winged viviparous female unless otherwise indicated. 



260 



