7 



JAN 25 i^c^;, 



Article XII. — Sixth Contribution to a Knoivledge of the Life 

 History of certain Little-knoirn Aphidida;^. By Clarence 

 M. Weed. 



THE CORN ROOT APHIS. {Aphis maidis {?) Fitch.) 



The literature and life history of the corn plant louse were 

 discussed at length in 1884 by Professor H. Garmanf, who 

 showed that at that time nothing definite was known concern- 

 ing the time or place of development of the sexed forms, the 

 connection between the root and aerial forms, or the manner 

 in which the insect passes the winter. In the article cited the 

 author adds nothing of importance to our knowledge of either 

 of these points, though the conjecture is made " that the lice 

 hibernated as alate viviparous females." 



In the autumn of 1885, however. Prof. Garman found a 

 single colony of oviparous females on the roots of corn in an 

 enclosed frame, and has described this form together with eggs 

 obtained from the abdomen by dissection J. Hence at the be- 

 ginning of the season of 1887 there remained to be determined, 



(1) whether the species normally hibernates in the egg state, 



(2) when and where the eggs are laid, (3) the time of appear- 



* The previous contributions of this series have been published 

 as t'ollows: first, "Psyche," Vol. V., pp. 123-134; second, " Psyche," 

 Vol. v., pp. 208-210; third, Bulletm Ohio Agricultural Experiment 

 Station, Second Series, Vol. I., pp. 148-152; fourth, Bulletin Ohio 

 Agricultural Experiment Station, Technical Series, Vol. I., pp. 111- 

 120; fifth, " Insect Life," Vol. III., pp. 285-293. 



The investigations on which the present article is based were 

 made in 1887 during my connection with the Illinois State Labora- 

 tory of Natural History, under the direction of Professor Forbes, to 

 whom I am indebted for the opportunity of publishing them at the 

 present time. The article was written in December, 1887, and is now 

 printed in its original form. C. M. VV. 



Hanover, New Hampshire, April, 1891. 



t Uth Kept. St. Ent. 111., pp. 23-33. 



X Misc. Essays on Economic Entomology, 188(5, pp. 4(5-48, 



