A SYNOPSIS OF THE APHIDIDAE 29 



has thought best to retain it in Monellis, at least for the time being. 



KEY TO CALIFORNIA SPECIES 



1. VI spur about equal to or slightly longer than VI base. Tibiae mostly pale. 



caryae Monell 



VI spur shorter than VI base. Tibiae entirely dark. Considerably larger than 

 preceding species calif ornicus (Essig) 



24. Callipterus californicus (Essig) 



Figures 63, 64 



Essig, Pom. Jour. Ent., vol. 4, p. 767, 1912. Monellia (orig. desc.). 

 Davidson, U. S. Dept. Agr., Bull. 100, p. 34, 1914. Monellia (list, key to 



walnut aphids). 

 Records. Juglans californica (California black walnut) ; Santa Paula. 



In 1912 Essig described this species from specimens taken near 

 Santa Paula in July, 1911. No other definite collections are known 

 to the writer, although Essig reports it as more or less abundant on 

 the California black walnut throughout the southern part of the state. 

 Davidson has not found it in the San Francisco Bay region, nor has 

 the author ever observed it, either in the bay region or in southern 

 California. 



25. Callipterus caryae Monell 



Figures 65, 66 



Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 31, 1879 (orig. desc.). 

 Clarke, Can. Ent., vol. 35, p. 249, 1903 (list). 

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

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

 Essig, Pom. Jour. Ent, vol. 4, p. 764, 1912. Monellia (list). 

 Davidson, U. S. Dept. Agr., Bull. 100, pp. 19-26, 1914. Monellia (dese. 

 all forms). 



Records. Juglans regia, J. californica; Berkeley, Stanford University, San 

 Jose, San Francisco Bay region. 



This species is more or less common in the San Francisco Bay 

 region on walnuts. Davidson has described all the forms and noted 

 its life history. The author has not taken the species. 



10. Genus Monellia Ostluml 



Oestlund, Minn. Geol. Nat. Hist. Surv., Bull. 4, p. 44, 1887. Type Aphis 

 caryella Fitch. 



This genus, as described by Oestlund, differs from Callipterus par- 

 ticularly in the position of the wings when the insects are at rest. In 

 Callipterus they are held roof-like over the body as is usual in aphids. 

 but in Monellia they are laid flat on the abdomen. It includes but 

 the one species, M. caryella (Fitch). 



