112 



PAPERS ON CEEEAL AND FORAGE INSECTS. 



G. Ainslie, at that time a special field agent of this Bureau, are about 

 the size of the typical Aphis maidi-radicis but they have circular 



sensoria — usually about three on the third segment of the antenna 



and have larger and darker markings on the thorax and abdomen 

 than has the typical Aphis maidi-radicis. This form is without much 

 question only a variety of the true Aphis maidi-radicis. It seems 

 best at the present time to recognize two species, viz, Aphis middle- 

 toni Thos., feeding on plants of the genera Aster and Erigeron, and 

 Aphis maidi-radicis Forbes, which feeds on corn, cotton, and many 

 wild plants. 



Fig. 58. — The corn root-aphis : Winged male, greatly enlarged, and antenna, highly magni- 

 fied. (Original.) 



Mr. J. H. Cowen describes an aphis under the name of Aphis 

 mcrithce-radicis which was taken on Mentha canadensis at Hotchkiss, 

 Colo., July 14. a This is the same as the form on the roots of corn, and 

 must therefore be considered a synonym of Aphis maidi-radicis. In 

 a recent letter Prof. C. P. Gillette, entomologist of the experiment 

 station, says: 



I have compared the type specimens with the slide (Aphis maidi-radicis) 

 you sent, and am a little in doubt as to whether there is sufficient difference to 

 consider the lice from the mint as a different species. I hardly think they are. 

 It also seems that Mr. Cowen's armoracea is also in all probability maidi- 

 radicis, but before finally deciding this matter I should like to compare the 



a Description published in "A Preliminary List of the Hemiptera of Colorado." 

 By C. P. Gillette and Carl F. Baker. Bui. 31, Colo. Agr. Exp. Sta., p. 121, 1895. 



