A SYNOPSIS OF THE APHIDIDAE 71 



82. Macrosiphum taraxici (Kalt.) 



Kaltenbach, Monog. d. Pflanzenlause, p. 30, 1743. Aphis (orig. desc.). 

 Theobald, Jour. Econ. Biol., vol. 7, p. 77, 1913 (desc.). 



Record. Taraxacum officinale; California (Wilson). 



H. F. Wilson stated to the author that he had taken this species 

 on dandelion (Taraxacum officinale} in California, although he gave 

 no date or locality record. 



83. Macrosiphum tulipae (Monell) 



Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 19, 1879. Siphonophora (orig. 



desc.). 

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



Records. Tulipa sp. ; Stanford University (Davidson); Liriodendron sp. ; 

 Berkeley, 1915 (Essig, Shinji). 



This species is not known to the author. It has been found on 

 tulips and on the tulip trees in the San Francisco Bay region by 

 Davidson, Essig, and Shinji. 



84. Macrosiphum valerianae (Clarke) 



Clarke, Can. Ent., vol. 35, p. 253, 1903. Nectarophora (orig. desc.). 

 Record. Valeriana offlcinialis; Berkeley (Clarke). 



In 1903 Clarke described this species from specimens taken on 

 heliotrope in Berkeley. Since then it has not again been found. 



24. Genus Myzus Passerini 



Passerini, Gli Afidi, 1860. Type Aphis ribes Linnaeus. 

 This genus is very closely related to Rhopalosiphum Koch, the 

 principal difference being in the shape of the cornicles. However, 

 some species fall easily into one or the other genus, depending entirely 

 upon what form one has. In this respect Rhopalosiphum persicae 

 (Sulz.) is particularly noticeable, the spring migrants having the 

 clavate cornicles of Rhopalosiphum, the fall migrants having the 

 cylindrical cornicles of Myzus. The author has followed Van der 

 Goot in taking out of this genus M. rosarum (Walker) and placing it 

 in the genus Myzaphis v.d.G. The antennal tubercles are lacking, 

 thus placing the species in the Aphidini instead of the Macrosiphini. 

 There are at present ten species of Myzus known to occur in Califor- 

 nia. Following is a key to them: 



