102 PAPEES ON CEKEAL AND FORAGE INSECTS. 



them. Cowpeas were lightly infested with all stages, except mi- 

 grants, although not located near heavily infested cotton. On beans 

 near infested cotton there were only a few of the root-aphis. Sweet 

 corn had been planted along a row of cotton, and this was quite gen- 

 erally infested with the " lice," plants that were near dead cotton 

 being most heavily infested. On radish, a colony was found on one 

 plant growing near badly infested cotton. Watermelon plants 

 which had just unfolded their first leaves and were near infested cot- 

 ton had an abundant supply of the root-aphis. In the case of each of 

 the cultivated plants mentioned above, Mr. Ainslie found evidence 

 that the " lice " were transferred from the cotton to the others by the 

 ants. The ants found in attendance were Lasius niger americanus, 

 Pheidole dentata comutata, and Pheidole vinelandica. 



UNCULTIVATED FOOD PLANTS. 



Beside the cultivated plants mentioned above, the root-aphis feeds 

 on various uncultivated species which are enumerated below. 



In Illinois it has been reported by Mr. J. J. Davis a on the roots 

 of numerous weeds and grasses, as follows : Smartweed (Polygonum 

 lap at hi folium) , knotweed (Polygonum persicaria) , crab grass (Digi- 

 taria sanguinalis) , purslane (Portulaca oleracea), dock (Rumex 

 crispus and R. altissimus), foxtail or pigeon grass (Setaria glauca 

 and 8. viridis), fleabane (Erigeron canadensis), mustard (Brassica 

 nigra), sorrel (Oxalis strict a) , plantain (Plantago major and P. 

 rugelii), pigweed (Amaranthus hybridus), and ragweed (Ambrosia 

 trifida). 



In the South it has been found on the following wild food plants : 6 

 At Chattanooga, Tenn., November 25, 1909, a few oviparous females 

 were found on thorny amaranth (Amaranthus spinosus). Vivip- 

 arous females were found on green amaranth (Amaranthus retro- 

 flexus) in a cornfield at Salisbury, N. C, October 12, 1909, in small 

 numbers. It was found rarely on Roman wormwood (Ambrosia 

 artemisiifolia) at Nathalie, Va., by Mr. J. A. Hyslop, July 10, 1908. 

 It was found in large numbers on the roots of Ambrosia artemisiifolia 

 in cotton fields and in waste ground at Marion, S. C, May 27 to June 

 5, 1909, and at Salisbury, X. C, May 22 and September 18, 1909. On 

 this plant they usually fed in fair-sized colonies along the main tap- 

 root, sometimes 10 inches deep in the ground. It was found on dog 

 fennel (Anthemis cotula) in very large colonies at the base of the 

 large roots, near the crown, at Marion, S. C, on May 29, 1909; on 

 shepherd's purse (Oapsella bursapastoris) in small numbers at Salis- 



a Davis, John June — Biological Studies on Three Species of Aphididse. Tech. 

 Ser. No. 12, Part VIII, Bur. Ent, U. S. Dept. Agr., February 20, 1909. 



h Records from Marion, S. C, are by Mr. G. G. Ainslie; those from other 

 localities are by the writer, unless otherwise stated. 



