CONTRIBUTIONS ON THE COKN KOOT-APHIS. 103 



bury, N. C, June 16, 1909; on lamb's-quarters {Ghenopodium album) 

 growing near a field of popcorn at Nathalie, Va., by Mr. Hyslop, 

 July 10, 1908, and on the same species growing beside a cornfield at 

 Salisbury, N. C, October 9-22, 1909 — in large numbers at both 

 places; on poverty weed {Diodia teres) in a cornfield at Salisbury, 

 N. C, July 28, 1909; on buttonweed {Diodia virginiana) in a corn- 

 field at Salisbury, N. C., September 25, 1909; on foxtail or pigeon- 

 grass (Setaria glauca) at Marion, S. C, June 3, 1909; in small num- 

 bers on cudweed {Gnaphalium purpureum) at Salisbury, N. C., May 

 22, 1909, and in large numbers on this plant at Marion, S. C, from 

 May 26 to June 14, 1909. It was numerous on sneeze weed (Helenium 

 tenui folium) at Rockmart, Ga., November 23, 1909, and at Marion, 

 S. C, May 29 to June 25, 1909 ; this plant, growing in open ground, 

 and in cotton and corn fields, was the most commonly infested weed, 

 and was heavily infested by the aphis in all stages. On pineweed 

 {Hypericum gentianoides) it was found in small numbers at Marion, 

 S. C, May 26, 1909. It was abundant on dwarf dandelion {Krigia 

 virginica) at Marion, S. C, May 26, 1909; large colonies were found 

 near the crown of the plant, but individuals were sometimes deep 

 down on the fibrous roots. It was found on Leptochloa filiformis at 

 Salisbury, N. C, September 13, 1909. On peppergrass {Lepidium 

 apetalum) at Ringgold, Ga., November 24, 1909, a few only were 

 found. Lepidium virginicum was a favorite food plant for this in- 

 sect at Marion, S. C, May 29 to June 14, 1909. It was found rarely 

 on toadflax (Linaria canadensis) at Marion, S. C, from May 26 to 

 June 1, 1909, and abundantly on plantain {Plantago aristata) at 

 Marion, S. C, June 3, 1909. It was numerous on plantain {Plantago 

 major) at Sharpsburg, Md., July 9, 1907, according to Mr. Kelly, and 

 at French Creek, W. Va., November 20, 1908, as reported by Mr. F. E. 

 Brooks in a letter to the Bureau. It was found on water pepper 

 {Polygonum hydropiperoides) , May 22, 1909, and on another of the 

 knotweeds {Polygonum muhlenbergii) , October 16, 1909, at Salis- 

 bury, N. C., but was not numerous on either of these plants ; it was re- 

 ported also as abundant on purslane {Portulaca oleracea) at French 

 Creek, W. Va. It was abundant on poverty weed {Diodia teres), at 

 Marion, S. C, May 31 to June 14, 1909, as nearly every plant of this 

 species w T as infested ; it occurred also on cocklebur {Xanthium cana- 

 dense) at Marion, S. C, June 1, 1909. 



This insect has been reported and described from Colorado by 

 Cowen on the roots of mint {Mentha arvensis) under the name of 

 Aphis menthce-radicis. 



All the known wild food plants infested by this species are native 

 to the eastern United States except the following : Amaranthus retro- 

 flexus, A. spinosus, and A, hybvidus, which have been naturalized 



