CONTENTS. 



Introduction 97 



Distribution 98 



History 98 



Experimental work in the South 100 



Uncultivated food plants 102 



Injury to corn 104 



Relation of ants to the root-aphis 105 



Natural checks 106 



Preventive measures 106 



Crop rotation 106 



Maintenance of soil fertility 106 



Early plowing, followed by frequent cultivations 106 



Repellents 107 



Injury to cotton 108 



Injury to asters 109 



Other cultivated food plants Ill 



Description and synonymy Ill 



The Erigeron root-aphis (Aphis middletoni Thos.) 113 



Uncultivated food plants . 114 



Cultivated food plants 115 



Attendant ants 115 



Laboratory and field experiments 116 



in 



