A SYNOPSIS OF THE APHIDIDAE 27 



21. Myzocallis quercus (Kalt.) 



Figures 31, 32, 58 



Kaltenbach, Monog. d. Pflanzenlause, p. 98, 1843. Aphis (orig. dese.). 

 Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. Callipterus (list). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). 

 Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. Callipterus (list). 

 Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). 

 Davidson, Jour. Econ. Ent., vol. 7, p. 130, 1914 (desc.). 



Records. Quercus agrifolia; Stanford University, San Jose, Penryn, Placer 

 County (Davidson) ; Q. lobata, Santa Clara County (Davidson) ; Berkeley, 1915 

 (Essig); Q. pedunculata, Berkeley, August, 1914; Q. douglasii, Stanford Univer- 

 sity, November, 1910, April, 1911 (Morrison); Q. robur, Oakland (Davidson). 



This is a variable species more or less common in the San Fran- 

 cisco Bay region and in the Sacramento Valley on various species of 

 oaks. When he first reported it Davidson was doubtful of its identity. 

 Later, however, it was identified by Peter Van der Goot 5 as this 

 species. 



22. Myzocallis ulmifolii (Monell) 



Figure 59 



Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 29, 1879. Callipterus (orig. 



desc.). 



Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909. Callipterus (list). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). 

 Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). 



Records. Ulmus sp., Stanford University (Davidson), "Ulmus americana, Wal- 

 nut Creek, October, 1913 (Davidson). 



Davidson reports this as common on elms in the San Francisco 

 Bay region. However, the author has never collected it. The follow- 

 ing brief descriptive notes are from an alate viviparous female, taken 

 in Walnut Creek by Davidson. The most distinguishing character is 

 the presence of a pair of small but prominent tubercles on the mid- 

 dorsum of the first and second abdominal segments. The usual 

 primary and accessory sensoria are present on V and VI. Secondary 

 sensoria (fig. 59) are present on the basal one-half to two-thirds of 

 III. These are transversely linear or oval, and number about six. 

 The cornicles are very short, being fully as broad at the apex as long. 

 Cauda and anal plate normal. Wings normal, radial vein indistinct, 

 first discoidal curving toward base of wing. Body length 1.836 mm., 

 width of thorax 0.578 mm., antennae total 1.309 to 1.326 mm., Ill 



s In 1917 George Shhrji (Ent. News, vol. 27, February, 1917) described three 

 species, M. essiggi n.sp., M. woodworthi n.sp., and M. hyalinus (Monell), all of 

 which are undoubtedly but varieties of this species, M. quercus (Kalt.). 



