280 THE CANADIAN ENTOMOLOGIST 



A REVIEW OF THE PTEROCOMMINI (Aphidid.^ Hom.). 



BY A. C. BAKER, WASHINGTON, D.C.* 



A few years ago the writer undertook a study of the Pterocom- 

 mini. In this he was helped, in her usual generous manner, by 

 Doctor Patch, who sent slides of some different species, 

 and by Professor Gillette, who loaned the writer slides of 

 the specimens he had. The recent paper by Wilson (1915) 

 on this tribe has called the writer's attention again to the 

 species. It seems worth while, therefore, to publish a few notes 

 on the group, since the writer's study showed some points at 

 variance with the results published by Wilson, and since Ptero- 

 comma popuiifolicv Fitch should be reinstated. 



In regard to the genera, the writer believes Wilson's view 

 correct, but in regard to species interpretation he is unable to 

 agree with him. These points of difference will be noted under the 

 species. 



Pterocomma populea (Kalt.). 



Two American species are made synonyms of this by Wilson. 

 They are beidahensis Ckll., and rufulus Davidson. Rnjulus as 

 indicated by specimens from Davidson is quite a different species. 

 The cornicles of populea from Spandau, Prussia, are about equal 

 in length to the hind tarsi. In nifulus, however, the cornicles are 

 nearly twice the length of the hind tarsi, bearing about the same 

 ratio as do those of bicolor Oest. Although rufulus proves to be 

 distinct from populea, it becomes a synonym of populifolicc Fitch, 

 a species not mentioned by Wilson. 



Pterocomma populifoliae (Fitch). 



Populifolice was described in 1851, and Fitch's notes give the 

 following numbers as representing the species: Nos. 6118-6121, 

 Nos. 9292-9302 and No. 3712. These are Fitch's personal numbers; 

 not the State Cabinet numbers. Of these numbers the following 



*Published by permission of the Chief of the Bureau of Entomology. 

 August, 1916 



