.J^^ 



Technical Series, No. 12, Part VIII. 



U. S. DEPARTMENT OF AGRICULTURE, 



BXJRE^TJ OF E:iSrTO]MOLOGJ^Y. 



L. 0. HOWARD, Entomologist and Chief of Bureau. 



MISCELLANEOUS PAPERS. 



BIOLOGICAL STUDIES ON THREE SPECIES OF 



APHIDID^. 



By JOHisr JUlSrE pAVIS, 



Of the Universihf of Illinois, Urbana, III. 



Issued February 20, 1909. 



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;to^l1l 



WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 



1909. 



