THE VEIJ^OW CLOVER APHIS. 



19 



map (fig. 10) show.5 the present known distribution of the species in 

 the United States, com])iled largely from records in this oilico made 

 by various mem])ers ot the staff. 



IN ASIA. 



In Asia the species under consideration was first reported from 

 Jodhpur, India, by Buckton (1899), and the writer has received 

 specimens from Dr. Das, presumably collected at Lahore, India. 



FOOD PLANTS. 



In America the universal food plant of this species is red clover 

 (Trifolium pratense), on which it is usually to be found on the under- 

 side of the leaves, living more or less solitary. We have reared it 

 also on white clover (Trifolium re pens). 



In 1909 Mr. T. II. Parks, at that time connected \vith the Bureau 

 of Entomology, conducted a se- 

 ries of experiments in testing 

 the abihty of Callipterus trifolii 

 to live on various })lants. The 

 plants used in these experiments 

 were wliite clover, sweet clover 

 (Melilotus spp.), timothy, spring 

 vetch, Japan clover (Lespedeza 

 spp.), sanfoin (Unohrychis sa- 

 tiva), alfalfa, bur clover (Medi- 

 cago maculata), alsike clover, 

 EngUsh clover, and mammoth 

 clover {Trifolium medium pe- 

 renne). The apliis would not 

 breed on the first seven plants 

 in these tests. On bur clover 

 it lived for a number of days 

 and then disappeared, the re- 

 sults in this case being inconclusive. On alsike, Enghsh, and mam- 

 moth clovers (all species of Trifolium) they bred without cUfTiculty. 



In India the species lives on lucern {Medicago sativa) — indeed 

 Buckton received reports that it was destructive to tliis plant — ^and, 

 as already stated, Dr. Das reports that it has never been found in 

 that country on Trifolium. We are as yet unable to explain why 

 this species lives on Trifolium and not alfalfa in America, whUe in 

 India it is found on alfaKa but a])parently not on Trifolium. 



Fiu. 10. -Map showiiig distribution of the yellow 

 clover aphis {CaUipterus trifolii) in the United 

 States. (Original.) 



