A SYNOPSIS OF THE APHIDIDAE 21 



in April, 1913, near Walnut Creek, Contra Costa County. According 

 to Davidson the sexes appear in October, egg laying occurring during 

 the first part of November. The eggs are laid at the axils of the new 

 buds and on the twigs or canes. These hatch the following spring, the 

 stem mothers being found in the early part of April. 



10. Eucallipterus tiliae (Linn.) 



Figures 7, 30, 33, 42, 50 



Linnaeus, Syst. Nat., vol. 2, p. 734, 1735. Aphis (orig. dese.). 

 Davis, Ann. Ent. Soc. Amer., vol. 2, p. 33, 1909. Callipterus (desc., biblio.). 

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

 Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. Callipterus (list). 

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

 Essig, Pom. Jour. Ent., vol. 4, p. 763, 1912 (list). 



Records. Tilia americana, Tilia curopea; Stanford University (Davidson), 

 Berkeley, August, 1914 (Essig) ; Stanford University, April to May, 1915; Berke- 

 ley, June, 1915. 



In the Sari Francisco Bay region this very pretty aphid is quite 

 common on basswood or linden. The author has taken it throughout 

 April, May, and June. Essig found it abundantly in August. It is 

 very easily recognized when found at rest on the under side of the 

 leaves of its host by the two black lines extending from the front o 

 the head along the margins of the thorax and joining with the costal 

 margins of the wings. It so appears that these lines are continuous 

 from the front to the tip of the wings. 



7. Genus Myzocallis Passerini 



Passerini, Gli Afidi, p. 28, 1860. Type Aphis coryli Goetze. 

 KEY TO CALIFORNIA SPECIES 



1. Wings hyaline 6 



Wings not hyaline, with portions shaded (fig. 262) .. 2 



2. Costal cell of wings hyaline (figs. 266, 267) 3 



Costal cell of forewings dusky or shaded (figs. 263, 264) 5 



3. First discoidal vein dusky, otherwise the wing is hyaline. VI with spur shorter 



than base. Apical one-half of III dusky (fig. 47). Cornicles pale. Found 

 on Alnus spp alnifoliae (Fitch) 



Wings not as above (figs. 266, 267). VI with spur either equal to or longer 



than base. Ill with less than apical one-half dusky 4 



4. Cornicles pale. Abdomen without dusky dorsal markings. On Quercus spp. 



maurerl Swain 



Cornicles dusky (fig. 62). Abdomen with dusky dorsal markings. On Casta- 



nea spp. and Quercus spp davidsoni Swain 



