74 MISCELLANEOUS STUDIES 



The black cherry aphis is found occasionally throughout Califor- 

 nia, but seldom in large enough numbers to be injurious. It infests 

 the terminal leaves of cherry, and sometimes other species of Prunus, 

 causing them to curl to a certain extent. Eggs are laid in the late fall 

 and early winter in the crevices of the bark and near the bases of the 

 buds. These hatch the following spring about the time the buds are 

 opening. The first few generations consist entirely of apterous 

 females. In the early summer the alate females appear, and con- 

 tinue to do so in each succeding generation until fall. In fact, after 

 the first of July, or thereabouts, the majority of the lice produced 

 are alate until the sexes appear in the fall. The first alate females 

 taken by the author were on June 7, 1915. However, on April 25, 

 1916, Essig found a few alate females in Berkeley. In August, 1914, 

 the apterae were also found in Berkeley. 



Van der Goot makes this species out of the genus Myzus, using it 

 as the type of his genus Myzmdes. The author is inclined to follow 

 him inasmuch as this is quite different from other members of this 

 genus, approaching Aphis in its robust form and separated from 

 that only by the length of the cornicles and presence of antenna! 

 tubercles. However, it has so long been considered as a species of 

 Myzus that it is best to leave it so. It is not a good policy usually to 

 form a new genus for one species, especially when it has for so long 

 been considered as a member of another genus. 



88. Myzus circumflexus (Buckton) 



Figure 175 



Buckton, Monog. Brit. Aphides, vol. 1, p. 130, 1875. Siphonopliora (orig. 



desc.). 



Gillette, Can. Ent., vol. 40, p. 19, 1908. M. vincae, n.sp. (desc.). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910. M. vincae Gill. (list). 

 Shinji, Can. Ent., vol. 49, p. 49, 1917 (list). 



Record. Vinca major; Stanford University (Davidson, Morrison), Berkeley, 

 1915 (Shinji), Los Angeles, March, 1917; Aesculus californicus, Alopecurus 

 pratensis, Asparagus, spp., Ceanothus sp., Cerastium viscosum, Cheiranthus chieri, 

 Cyrtonium falcatum, Digitalis purpurea, Fuchsia sp., Gladiolus sp., Plantago sp., 

 Senecio mikanioides, Sisymbrium sp., Solanum spp., Stachys bullata, Tropaeolum 

 sp., Symphoricarpus racemosus; Berkeley, 1915, 1916 (Essig, Shinji) : Viola tri- 

 color; Stanford University, March, 1915; Berkeley, 1915 (Essig, Shinji): 

 Rioliardia africana; Pomona, 1909 (Essig); Stanford University, March, 1915; 

 Berkeley, March, 1915 (Essig) ; San Diego, May, 1916; Los Angeles, March, 1917. 



This very common aphid is found in the spring on a large variety 

 of host plants throughout California. At times it may become so 



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