134 MISCELLANEOUS STUDIES 



34. Genus Myzaphis Van der Goot 



Van der Goot, Ziir Systematik der Aphiden, Tijdscrift voor Entomologie, 

 vol. 56, p. 96, 1913. Type Aphis rosarum Walker. 



The author believes that this genus of Van der Goot's should be 

 accepted for the two following species: Aphis abietina Walker and 

 Aphis rosarum Walker. A. rosarum has usually been considered as 

 belonging to the genus Myzus, but the absence of antennal tubercles 

 excludes it from that genus (see figs. 306-308, 313). The cornicles 

 and cauda are not typical of Aphis, and these together with the dis- 

 tinctive frontal tubercle on the head and the absence of lateral body 

 tubercles distinguish it from Aphis. Consequently this genus should 

 be recognized. Following is a key for separating the two known 

 species, both of which occur in California : 



Cornicles slightly clavate (figs. 312, 315), shorter than III. Ill tuberculate, IV 



without sensoria (fig. 309). Found on Rosa spp rosarum (Walker) 



Cornicles cylindrical (fig. 197), equal to or longer than III. Ill with 9 to 12 

 rather large secondary sensoria, IV with 1 to 4 (fig. 196). On conifers. 



abietina (Walker) 



158. Myzaphis abietina (Walker) 



Figures 196, 197 



Walker, Ann. Mag. Nat. Hist., vol. 3, p. 301, 1848. Aphis (orig. desc.). 

 Wilson, Proc. Ent. Soc. Brit. Columbia, June, 1915 (desc.). 

 Record. Picea excelsa; San Francisco, March, 1915 (Compere). 



The only report of this species in America is that of Wilson, who 

 found it on spruce (Picea sp.) at Vancouver, British Columbia. On 

 March 26, 1915, Harold Compere of San Francisco took a number of 

 specimens of this species on the twigs of Norway spruce (Picea 

 excelsa) in Golden Gate Park, San Francisco. The specimens are in 

 Essig 's and the author's collections. 



159. Myzaphis rosarum (Walker) 



Figures 308 to 317 



Walker, Ann. Mag. Nat. Hist., voL 3, 1848. Aphis (orig. desc.). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 379, 1910. Myzus (list) 

 Eecords. Rosa spp.; Stanford University (Davidson); Santa Paula (Essig), 

 San Diego, March to July, 1916. 



This species has been reported in the San Francisco Bay region 

 by Davidson and in Santa Paula by Essig. In the Bay region it is 

 rather scarce and is second to Macrosiphum rosae (Linn.) in abun- 

 dance on roses. The author has taken it at Stanford University in 

 1915, and in San Diego several times in 1916. In San Diego in 1916 

 it was by far the most abundant rose-infesting aphid. The author 



