A SYNOPSIS OF THE APHIDIDAE 119 



137. Aphis oregonensis Wilson 



Wilson, Trans. Am. Ent. Soc., vol. 41, p. 92, 1915 (orig. desc.). 

 Record. Artemisia tridentata, California (Wilson). 



Wilson stated to the author that he had taken this species in 

 California although he gave no locality or date records. On the 

 strength of his statement it is included among the California aphids. 

 The author has never seen specimens of it. 



138. Aphis persicae-niger Smith 



Figures 223, 224 



Smith, Ent. Am., p. 101, 1890 (orig. desc.). 



Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). 



Gillette, Jour. Econ. Ent., vol. 1, p. 308, 1908 (desc.). 



Weeks, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 244, 1912 (list). 



Jones, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 318, 1912 (list). 



Games, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 399, 1912 (list). 



Wood, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 570, 1913 (list). 



Records. Prunits spp. ; throughout California. 



This species is ordinarily found infesting the tender twigs and 

 leaves of peach in the spring and early summer. Occasionally it is 

 found on nectarine, plum, and cherry. There are two records of its 

 occurrence on cherry known to the author; one in San Jose in May, 

 1912, by Davidson, and one in El Cajon, San Diego County, in May, 

 1916, by the author. Definite reports of its presence on peach come 

 from Los Angeles, Placer, Riverside, San Benito, San Bernardino, 

 San Diego, Santa Clara, and Tehama counties. In May, 1916, the 

 author observed it doing considerable damage to a young peach orchard 

 in the El Cajon Valley, San Diego County. Many of the twigs and 

 some of the larger branches were killed back for several inches, due 

 to the ravages of this insect. 



The Hippodamia ladybird and the larvae of a syrphid fly were 

 abundant and devouring vast numbers of the aphids. However, it is 

 not often that this appears abundant enough to cause any great 

 amount of damage. 



Its life history, although not thoroughly worked out, is interesting. 

 The following brief summary is from Essig: 17 



The insect winters over on the roots of the peach trees, where it may also be 

 found in the summer. The first aphids appear above ground very early in the 



17 Essig, E. O., Beneficial and injurious insects of California; ed. 2. Suppl. 

 Mon. Bull. Cal. Comm. Hort., vol. 4, pp. 91-92, 1915. 



