124 MISCELLANEOUS STUDIES 



Francisco Bay region, 1914 (Davidson) ; Pasadena, May, 1917 (Boy E. Camp- 

 bell) : Artemisia spp.; San Francisco Bay region, 1914 (Davidson); Berkeley, 

 1915 (Essig) : Aster sp. ; San Diego, January, 1916; Ontario, January, 1917: 

 Bacchari* pilularis ; Berkeley, 1915 (Essig), Stanford University, 1916 (Ferris): 

 Calendula officinale; Berkeley, 1915 (Essig); San Diego, March, 1916; Riverside 

 and Orange, February, 1917: Chrysanthemum sp. ; Berkeley, 1914 (Essig); Octo- 

 ber, 1915; Menlo Park, San Mateo County, March, 1915; San Diego, January, 

 1916; La Jolla, February, 1916; Ontario, January, 1917: Cytisus proliferus; 

 Berkeley, 1915 (Essig): Gnapholium sp. ; Walnut Creek, 1914 (Davidson): Grin- 

 delia cuneifolia; Walnut Creek, 1915 (Davidson): Hclianthus annuus; San Frau- 

 cisco Bay region, 1914 (Davidson): Eumex sp. ; Stanford University, March, 

 1915: Salix sp. ; Berkeley, 1915 (Essig): Senecio spp.; Stanford University, 1909, 

 1910, 1914 (Davidson) ; Santa Paula, 1911 (Essig) ; Palo Alto, February, 1915. 



This is a very common species throughout California, occurring 

 on many host plants, particularly the Compositae. It is found most 

 commonly in the early spring on asters, marigolds, and chrysanthe- 

 mums in southern California, and on German ivy and amsinckia in the 

 San Francisco Bay region. For sometime it was believed to be Aphis 

 bakeri Cowen, but its variety of host plants so widely different from 

 those of bakeri, led to its being identified as a distinct species. It is 

 one of the most common in the state, as a glance at the collection 

 records will show. 



147. Aphis setariae Thomas 



' Figures 246, 247 



Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 5, 1878 (orig. desc.). 

 Williams, Univ. Neb. Studies, vol. 10, p. 141, 1910 (desc.). 



Record. Prunus domestica; San Francisco Bay region (Davidson). 



In some parts of the country this plum louse becomes abundant 

 enough to cause serious damage, but it has never been observed to be 

 so in California. Davidson writes that he has found it sparingly a few 

 times in the San Francisco Bay region. The author has never collected 

 it, but has had access to specimens from Morrison, taken in Indiana. 



148. Aphis spiraecola Patch 



Patch, Maine Agr. Exp. Sta,, Bull. 233, p. 270, 1914 (orig. desc.). 



Records. Spiraea spp.; Stanford University, 1912 (Morrison); Walnut Creek, 

 Contra Costa County, 1916 (Davidson). 



In the San Francisco Bay region there is a small aphid very 

 similar to Aphis pami De Greer found attacking meadowsweet. David- 

 son and Morrison, who have both observed it, believe it to be this 

 species. The following brief descriptive notes are from alate females 



