116 PAPERS ON CEREAL AND FORAGE INSECTS. 



The following ants were found associated with this species on the 

 roots of Erigeron canadensis: By Mr. Hayhurst — Pheidole sp. at 

 Arkansas Cit} 7 , Kans., Solenopsis geminata Fab. and Dorymyrmex 

 pyramicus Roger at Kingfisher, Okla., and Iridomyrmex analis Ern. 

 at Newkirk, Okla.; by Mr. Kelly — Solenopsis molesta Say, Lasius 

 inter jectus Mayr, Monomorium minutum Mayr var. minimum Buck- 

 ley, and Ponera coarctata Latr. var. pennsylvanica Buckley, at Wel- 

 lington, Kans. ; by Mr. G. G. Ainslie — Pheidole vinelandica Mayr at 

 Marion, S. C. The ant Prenolepis imparis Say was found by the 

 writer associated with this root-aphis on Aster ericoides at Rock- 

 mart, Ga. 



LABORATORY AND FIELD EXPERIMENTS. 



Many laboratory experiments were carried on by the writer at 

 Salisbury, N. C, to determine the adaptability of Aphis middletoni 

 to other food plants. Wingless females were taken from the roots of 

 Erigeron ramosus and transferred to sprouting corn and to sprouting 

 cotton in vials, and although this experiment was tried several times, 

 using several females each time, it was unsuccessful. A number of 

 experiments were tried, using the females from the roots of Aster 

 subulatus. These also were unsuccessful, with the following single 

 exception: Females removed from the roots of Aster subulatus to 

 sprouting cotton, August 30, produced young which succeeded in 

 supporting themselves on the cotton. Several generations were pro- 

 duced, but the aphides never acquired the characters of Aphis maidi- 

 radicis. Oviparous females were produced October 9 and others were 

 produced later, the experiment being closed November 22. 



Mr. Kelly carried on similar experiments at Wellington, Kans., in 

 1908, which were more successful. His experiments, in brief, are as 

 follows : 



Experiment D. — A stem-mother was removed from the roots of a young 

 Erigeron plant May 9 and placed on a young Erigeron plant in a vial. The 

 young which she produced were placed on sprouting corn in vials. 



Experiment D 1 . — One young born May 10(?) became adult May 19 and pro- 

 duced 45 young between May 20 and June 7. 



Experiment F 1 . — One larva removed from cage D May 12, matured May 

 22 ( ?), and produced 35 young from May 22 to June 2. 



Experiment F 2 . — One larva from cage F\ born May 22, matured May 30, and 

 produced 32 young from May 30 to June 7. 



Experiment F 3 . — Larvae removed from the above experiment May 30 did not 

 mature on corn. 



Mr. G. G. Ainslie carried on similar experiments in 1908 at Clem- 

 son College, S. C. The most successful experiment was as follows : 



A few aphides from the roots of Erigeron canadensis were placed 

 on sprouting corn in a vial, October 30; by November 9 four young 



