THE CANADIAN ENTOMOLOGIST. 247 



A LIST OF CALIFORNIA APHIDTD^. 



BY WARREN T. CLARKE, BERKELEY, CALIF. 



Our knowledge of the group Apliididaj in California has been.h'mited 

 in the jiast to certain forms that were of economic importance in their 

 relations to cuhivated crops. No systematic list of these interesting 

 insects has heretofore been attempted in this region, and this has not been 

 due to any lack of material, for the varying conditions of climate here 

 seem to be particularly favorable to them. 



In Hunter's list of the Aphididse of Nortli America (Bull. No. 60, 

 Iowa Ag. Ex. Sta., 1901) we find nine forms that may be considered as 

 reported from California. Only five of these forms are directly referred to 

 this State, while the other four are stated to be found, as in the case of 

 Nectarophora avence, Fabr., " throughout the United States." One of the 

 five forms directly referred to the State is Aphis mali, Fabr. Tne writer 

 is doubtful of the occurrence of mali here, and believes that other species 

 have been confused with it, and therefore does not include it as a 

 CaHfornia form. With this exception the following list is made up from 

 the reported Aphididae of California and from the writer's own collections 

 in the State during the past eighteen months. 



Forty-three species are listed, including ten new species. Thi^ num- 

 ber does not by any means exhaust the group so far as this State is C'Ui- 

 cerned, as it represents but fe^v localities, yet it is believed that the 

 presentation of the list at this time is desirable, in that it may stimulate 

 further study of the group by other observers. 



Table of Genera. 



A. Third discoidal vein wanting Phylloxera. 



AA. " " " simple Pemphigus. 



AAA. " '• •' one-branched .Schizoneura. 



A A. A A. " " •' two-branched. 



B. Antennae five-jointed Lachnus. 



BB. Anlennie seven-jointed. 

 C. Style long. 



D. Frontal tubercles toothed internally Phorodon, 



DD. Frontal tubercles not toothed internally. 



E. Frontal tubercles approximate Nectarophora. 



EE. Frontal tubercles distant Myzus. 



CC. Style short. 



