ULLETIN 



UxNITED STATES GEOLOGICAL AND GEOGRAPHICAL SURVEY 

 OF THE TERRITORIES. 



Volume V. 1879. Nu^iber 1. 



Art. lo — Motes ©la the Aphididse of the United States, 



with descHptions of species occHi'FiMg West of the 



Mississippi. 



By Chas. V. Riley and J. Monell. 



PART I. 



BIOLOGICAL NOTES ON THE PEMPHIOm^, WITH DE- 

 SCEIPTIONS OF NEW SPECIES.— C. V. Eiley, Ph. D. 



The object of the i)resent paper is to set forth some interesting biolo- 

 gical facts relating to the gall-making PempMgince,* and which were pre- 

 sented in abstract at the late meeting of the American Association for 

 the Advancement of Science. These facts have a special interest just 

 at this time on account of the close relationship between the insects of 

 the sub-family in question and the notorious Grape-vine Phylloxera 

 [Phylloxera vastatrix). 



The life-history and agamic multii)lication of the Plant-lice {AiMdkJm) 

 have always excited the interest of entomologists, and even of anatomists 

 and embryologists not especially given to the study of insects. The life- 

 history, however, of the gall-making species belonging to the Pemphigince 

 has baffled the skill of observers more than that of any other group. 

 All of the older writers, in treating of the different gall -producing 

 PempMgina' of Europe, have invariably failed to trace the life-history of 

 any of the species after the winged females leave the galls, and, with 

 few exceptions, have erroneously inferred that the direct issue from the 

 winged females hibernates somewhere. The most recent production on 

 the subject is a paper published the present year in Cassel, Germany, by 

 Dr. H. F. Kessler, on the life-history of the gall-making Plant-hce 



* This term is used in the suh-family sense, in accordance with most common usage, 

 and not in the tribal sense, as emi)loyed by Buckton in his Monograph of liritish 

 Aphides, 1875. 



Bull. V, 1 1 



