98 PAPERS ON CEREAL AND FORAGE INSECTS. 



An aphis frequently infesting the roots of Erigeron, canadensis has 

 generally been considered as belonging to this species. It is included 

 in the latter part of this paper for this reason, but, as explained 

 farther on, it now seems to be distinct from the corn root-aphis, and 

 is therefore discussed under the name Aphis middletoni Thomas, 

 with the description of which it seems best to agree. 



The illustrations of the oviparous female and wingless male of the 

 corn root-aphis (figs. 56 and 57) are kindly loaned for use in this 

 paper by Dr. S. A. Forbes, state entomologist of Illinois. 



DISTRIBUTION". 



According to the letters of inquiry in the files of the Bureau of 

 Entomology the corn root-aphis has been seriously injurious to corn 

 in the following States (fig. 59) : New Jersey, eastern Pennsylvania, 

 Maryland, Virginia, West Virginia, North Carolina, South Caro- 

 lina, Ohio, Indiana, Illinois, and Oklahoma. Besides these States 

 it has been reported in literature as injuring corn in New York, Min- 

 nesota, Iowa, Missouri, Nebraska, Kentucky, Mississippi, Louisiana, 

 and Colorado. In addition to the States mentioned above the root- 

 aphis was collected from the roots of corn at Sioux Falls, Huron, and 

 Aberdeen, S. Dak., by Mr. Kelly of the Bureau of Entomology, and 

 what is supposed to have been this species was collected from corn 

 roots at Sterling, Kans., by Mr, C. N. Ainslie, also of this Bureau. 

 Injuries to cotton have occurred in the coastal plain of the Carolinas. 

 An aphis supposed to be of this species has been reported to the 

 Bureau as injurious to cultivated asters from the following States: 

 Massachusetts, Rhode Island, Connecticut, New York, New Jersey, 

 Delaware, Maryland, Ohio, and Illinois. The species is apparently 

 distributed in the United States throughout almost the entire region 

 east of the Rocky Mountains wherever corn is grown. 



It has been reported from Maine in a letter to the Bureau, but on 

 what food plant it was taken is not known. Although Mr. Kelly 

 searched for it in North Dakota, Montana, and Wyoming he did not 

 find it in those States. It has not, up to the present time, been re- 

 ported from New Hampshire, Vermont, Michigan, Wisconsin, 

 xVrkansas, or southern Florida. It is probably present in Mexico, 

 although we have found no reference to it in any of the foreign 

 literature. 



HISTORY. 



Although the corn root-aphis (figs. 54-58) was not described and 

 named until 1891, it has apparently been known to the corn growers 

 of this country for nearly a century and possibly much longer. 

 James Worth, in an article entitled " Observations on Insects " read 

 before the Agricultural Society of Bucks County, Pa., July 29, 1822, 



