CONTRIBUTIONS ON THE CORN ROOT- APHIS. 115 



Aster ericoides, from September 18 until November 15, 1909. Sexual 

 forms were found on this plant at Salisbury, N. C, November 15, 

 1909, and at Eockmart, Ga., November 23, 1909-. Cosmos (Cosmos 

 bipinnatus) , which had escaped from cultivation and was growing 

 wild along the roadside at Salisbuiy, was also found infested by 

 this aphis in October, and on November 5 sexual forms were present 

 on the roots of the plant. 



CULTIVATED FOOD PLANTS. 



Specimens of an aphis which attacked the roots of China asters 

 (C allistephus hortensis), received from Dr. E. P. Felt, of Albany, 

 N. Y., apparently belong to this species, but specimens collected from 

 the roots of cultivated aster at Chicago by Mr. J. J. Davis are with- 

 out any doubt Aphis maidi-radicis. It is yet an open question to 

 which species the insect which has been attacking cultivated asters 

 in the North Atlantic and New England States belongs. The species 

 which attacks dahlias and French artichokes (Cynara scolymus) 

 belongs to one of these two, but to which one can only be settled by 

 obtaining more material. Cosmos bipinnatus was found infested 

 by Aphis middletoni October 6, 1909, at Salisbury, N. C. The writer 

 has found no record in the American or foreign literature of an 

 aphis infesting the roots of dahlia, artichoke, or cosmos. Cosmos 

 bipinnatus* which grows wild in Mexico, may have been one of the 

 original food plants of this species. 



ATTENDANT ANTS. 



The Erigeron root-aphis is attended by a larger number of ant 

 species than is Aphis maidi-radicis. It is seldom found associated 

 with Lasius niger~L. var. americanus Emery, which commonly attends 

 the corn root-aphis, but is ordinarily found attended by a medium- 

 sized black ant, Cremastog aster lineolata Say, which on the other 

 hand seldom attends the corn root-aphis. 



Lasius niger americanus was observed associated with this species 

 by Mr. J. A. Hyslop at Nathalie, Va., July 9, 1908, and by the writer 

 at Salisbury, N. C., on Cosmos bipinnatus November 5, 1909, and on 

 Aster ericoides November 15, 1909. 



Cremastog aster lineolata was observed associated with this root- 

 aphis by the writer at Salisbury, N. C; by Mr. G. G. Ainslie at 

 Clemson College, S. C, and by Mr. Paul Hayhurst at Ponca City, 

 Okla., Newkirk, Okla., and Wellington, Kans. At Winfield, Kans., 

 it was found by Mr. Hayhurst associated with the varieties of this 

 ant known as opaca and clara. This ant and aphis were also found 

 associated at Wellington, Kans., by Mr. E. O. G. Kelly. 



