Vol. XXvii] ENTOMOLOGICAL NEWS. 359 



The Identity of Eriosoma querci Fitch (Aphididae, 



Horn.).* 

 By A. C. BAKER, Bureau of Entomology, Washington, D. C. 



The species of Anoecia upon Cornus in America has for 

 many years been considered to be corni Fab., of Europe. 

 While working over the species in 1909, the writer was con- 

 vinced that the American form is distinct from the European. 

 At that time he had no European specimens and was unable, 

 therefore, to prove or disprove his suspicions excepting by 

 literature. Since that time he has studied specimens from sev- 

 eral localities in France, Germany, Belgium, Russia, the Ma- 

 deira Islands and Japan. All of this material and a careful 

 study of the European literature and the forms met with in 

 this country have proven that the American form is quite a dis- 

 tinct species. It, however, winters upon plants of the same 

 genus as does the European corni and migrates in summer to 

 grass roots as does the European species. The Japanese form 

 seems to agree with the European. 



It will be seen by the accompanying figures that the fall 

 migrants of the two species are quite different. The third 

 segment of the antennae of corni is armed with twelve to nine- 

 teen sensoria and these are narrow, not subcircular, in shape. 

 The average number in all the forms examined by the writer 

 is between twelve and thirteen. Segments IV and V have from 

 four to six similarly shaped sensoria. The fall migrant of 

 the American species on the other hand has usually six or 

 seven sensoria and these are oval or almost circular in shape, 

 very different from the narrow elongate sensoria met with on 

 corni antennae. Segments IV and V have two or three sen- 

 soria and these are oval or subcircular. The spring migrant 

 of the American species shows two or perhaps three sensoria 

 upon Segment III. These vary greatly in size. Sometimes they 

 will be minute and sometimes there will be one large one and 

 one small one. Again in other specimens some will be absent 

 altogether. This also holds true of the sensoria upon Segment 

 The early summer alate of corni has about six or seven 



*Published by permission of the Chief of the Bureau. 



