62 Journal ot Rnti)m<ili)t;v and Zoology 



primary 2 mm., secondary 1.2 mm. The cornicles are black, imhi- 

 cated, cylindrical, somewhat larger near the base, the outer margin 

 straight, the inner margin as illustrated (Figure 1, W. corn. ) . The 

 length 0.10 mm., greatest width 0.05 mm. The cauda and anal 

 l)late are black and as illustrated (Figure 1, W. cauda). 



Relationship — This species has been carefully checked with 

 Aphis reticulata Wilson, A. oregonetwiis Wilson, A. hermistonii Wil- 

 .son, A. tridentatac Wilson, A frigidae Oestlund, and Aphis artc- 

 m;.sToto Williams occurring in Oregon on Arteviisia tridcntata, and 

 does not agree with any of them or other closely related species. 



Host — The species occurs in dense colonies on the apical twigs 

 of old man or California sage, Artemisia calif ornica Less. 



Locality — In Laguna Canyon one-half mile above Laguna 

 Beach, California. 



Date of Collection — July 13, 1921. 



COTYPES — The above description was made from a series of 

 cotypes consisting of ten slides and over one hundred mounted indi- 

 viduals. The cotypes are in the author's collection. 



The species is named after Dr. Wm. A. Hilton, Professor of 

 Zoology, Pomona College, under whose su])ervision. inspiration and 

 energy a most wonderful type of biological in.struction is being 

 given each summer at the Laguna Beach Laboratory. 



Figure 1. — Aphis hiltoni n. sp. 



A. Apterous viviparous female; A. tub., body tubercles of 

 apterous female; i, prothoracic; ii, front abdominal; iii, posterior 

 abdominal; A. corn., apterous cornicle; A., cauda, apterous cauda 

 and anal plate; At. t., apterous tarsus: A. ant., apterous antenna; 

 W, wings; W. ant., antenna of winged female; W. corn., cornicle of 

 winged female; W. cauda, cauda and anal plate of winged female; 

 W. tub., body tubercles of winged female; i. prothoracic; ii, front 

 abdominal; iii, posterior abdominal. 



