100 



PAPERS OX CEREAL AND FORAGE INSECTS. 



this species have been continued till now its life history and habits 

 as a corn insect in Illinois are very well understood. 



Until recently it has not been so thoroughly studied in other. sec- 

 tions of the country, especially in the Southern States, where its life 

 history and habits are widely different from what they are in Illinois. 

 Some of the results of these more recent studies which have been made 

 by the Bureau of Entomology are therefore presented in this paper. 



EXPERIMENTAL WORK IN THE SOUTH. 



The following laboratory experiments were carried on by the 

 writer at Salisbury, X. C., to determine the identity of the aphides 



Fig. 55. 



-The corn root-aphis : Winged, viviparous female, greatly enlarged, and antenna 

 of same, highly magnified. (From Webster.) 



found on the roots of corn, cotton, and various weeds. The method 

 used was to remove wingless females of Aphis maidi-radicis from the 

 roots of the various food plants and to place them either on sprout- 

 ing cotton or on sprouting corn in vials. A plug of wet absorbent 

 cotton was placed in the bottom of the vials. The roots of the plants 

 would grow down into this and would keep alive and furnish 

 nourishment for the aphides for about a week. Cotton plants proved 

 the best for use in these experiments because they were not so subject 

 to attack by fungi as were corn plants. The vials were kept in the 

 dark. The aphides usually attack the leaves of the cotton in pref- 

 erence to the stem. 



Ambrosia artemisiifolia (bitterweed). — Experiment a: Apterous vivipara 

 were removed from the roots of this plant, September 18, and placed on sprout- 



