117 



135. Aphis nerii Fonsc. 



Figures 221, 222 



Boyer de Fonscolombe, Ann. Ent. Soc. France, vol. 10, p. 167, 1841 (orig. 



desc.). 



Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. A. lutescens Monell (list). 

 Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. A. lutescens Monell (list). 

 Essig, Pom. Jour. Ent., vol. 3, p. 401, 1911. A. lutescens Monell (desc.). 

 Essig, Pom. Jour. Ent., vol. 3, p. 530, 1911 (dese.) 

 Branigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 53, 1915 (list). 



Eecords. Asclepias mexicana; Stanford University (Davidson) ; Stanford 

 University, October, 1910 (Morrison) ; Penryn, Placer County (Davidson) ; south- 

 ern California (Essig); Berkeley, July to September, 1915: Nerium oleander; 

 southern California (Essig) ; Sacramento (Branigan) ; Berkeley, August to Decem- 

 ber, 1915 j San Diego, 1916. 



In the late spring, summer, and early fall milkweeds throughout 

 the state are often seen to be infested with a bright yellow and black 

 aphid. In the fall and early winter this same species is found infest- 

 ing oleanders. Where oleanders are present but no milkweeds this 

 aphid can be found from spring until winter on the oleander, as 

 observed during 1916 in San Diego. 



Heretofore the species on oleander and milkweed have been con- 

 sidered as distinct, the former being called A. lutesc&ns Monell, the 

 latter A. nerii Fonsc. According to a note from J. J. Davis the 

 species on milkweed could not be A. lutescem Monell. Following are 

 extracts from his letters concerning this point : 



I am wondering whether you have ever found winged specimens on Asclepias 

 that do not bear the black markings at the base of the cornicles. All the speci- 

 mens that I have collected and which Mr. Monell has collected in recent years have 

 these black markings at the base of the cornicles in the winged forms. However, 

 in referring to an old note from Mr. Monell, he says that it would seem hardly 

 possible that he could have missed these dark spots if they had been present in 

 the specimens from which he drew his description for Aphis lutescens, and re- 

 marks further that he is not sure that he has ever seen A. lutescens alive since he 

 first described it. I am wondering if lutescens is not really asclepiadis of Pass- 

 erini and whether our other common species on Asclepias and Nerium is not 

 nerii Fonsc. 



During the summer of 1915 the author found this species on 

 Asclepias in the Botannical Gardens at the University of California. 

 During July and August it was quite abundant; in fact, it was 

 especially thick on the stems and undersides of the leaves and blossoms. 

 However, in the latter part of August it seemed to be getting less 



