CONTRIBUTION TO A KNOWLEDGE OF THE AUTUMN LIFE- 

 HISTORY OF CERTAIN LITTLE-KNOWN AFHIDIDAE. 



BV CLARENCE MOORES WEED, COLUMBUS, OHIO. 



I doubt whether our present knowl- 

 edge of any of the hirger families of 

 American insects is in a more chaotic 

 and deplorable state than that relating 

 to the aphldidae. Though much has 

 been written concerning these insects, 

 comparatively few species have been 

 described in more than one or two of 

 their several forms; and with a few 

 notable exceptions, almost none of the 

 authors who have described species 

 have attempted to trace their seasonal 

 life-histories. Doubtless this condition 

 of things is due largely to the obscurity 

 surrounding the subject, and the imper- 

 fect knowledge of the economy of the 

 group both in this country and Europe? 

 as well as to the difficulty of preserving 

 specimens in satisfactory' condition for 

 study. The recent researches of Licht- 

 enstein, and Kessler in Europe, and of 

 Riley, Forbes, and others in this 

 country, have given us, however, a 

 substantial working- basis for the tracing: 

 of the life-histories of these insects, and 

 our knowledge ought hereafter to make 

 more satisfactory progress. 



This paper presents a part of the 

 results of field work during the autumn 

 of 1SS7 on species which have hereto- 

 fore been very little studied, and about 

 whose autumn life-histories nothing has 

 been recorded. I am under obligations, 

 for many favors received, to my co- 

 workers in the Illinois State Laboratory 

 of Natural History, especially to the 

 Director, Prof. S. A. Forbes, under 

 whose general instructions the investi- 

 gations have been carried on. 



Aphis cornifoliae Fitch. 



This species was first described by 

 Dr. Fitch, in 185 1, in the Fourth report 

 of the regents of the University of New 

 York (p. 65), from apterous females 

 found on Cornus paiiiculata. The 

 description is very brief, and as the 

 date of collection is not given we have 

 no means of knowing whether his 

 specimens were oviparous or viviparous, 

 though they were probably the latter. 

 So far as I can learn the species has not 

 since been recognized, except b}' Prof. 

 Oestlund who says that it is rather 



