THE CANADIAN ENTOMOLOGIST 289 



5. Lateral tubercles of the abdomen about equal in length to the 



second antennal segment steinheili. 



Lateral tubercles of abdomen considerably shorter than the 

 second antennal segment beulahensis. 



6. Cornicles nearly twice as long as the hind tarsi 7. 



Cornicles much more than twice as long as the hind tarsi 8. 



7. LTnguis of segment \ I of antennae about equal in length to the 



cornicle and more than twice as long as base hicolor. 



Unguis of segment YI of antenna? usually shorter than the 

 cornicle and less than twice as long as base popidifolicB. 



8. Cornicles cylindrical or slightly tapering farinosa. 



Cornicles much swollen in the middle 9. 



9. Cornicles bright orange in colour salicis. 



Literature, 



185L Fitch, Asa.— Cat. Hom., N.Y. State Cab. Nat. Hist., p. 66. 



1887. Oestlund, O. W. — Synopsis of the Aphidid» of Minnesota. 

 Bull. No. 4, Geo. and Nat. Hist Survey of Minn. 



1910. Davis, J. J. — A List of the Aphididee of Illinois, with notes 

 on some of the species. In Journal of Econ. Ent.,Vol. Ill, 

 p. 489. 



1911. Davis, J. J.— Williams, "The Aphidida^ of Nebraska," A 

 Critical Review. llni\ersity studies, \5. of Neb., Vol. XI, 

 p. 259. 



1913. Patch, E. M.— Aphid Pests of Maine— The Willow Family 

 —Bull. Agr. Exp. Station, Me. No. 213., p. 89. 



1913. Del Guercio, G. — Generi e Speci Nuove di Afididi — Redia 

 IX, p. 178. 



1915. Wilson, H. F. — A Synopsis of the Aphid Tribe Pterocom- 

 mini — In Annals of the Ent. Soc. of America, Vol. VIII, 

 p. 347. 



The remaining literature on the tribe is cited in Wilson's 

 paper. 



