232 THE CANADIAN ENTOMOLOGIST. 



The fact that the under surface in fraxini is bright and white as in 

 relicta, while the upper surface of the wings is more obscure than in the 

 American species, is worthy of note. I think that if we may localize the 

 features of variation in markings as occurring first on the upper surface 

 of the wings, especially on the primaries, we may draw some conclusions 

 as to the relationship between different species of Noctuidse from the 

 degree of similarity beneath. I have elsewhere shown that the variability 

 of C. relicta in the tone of the fore wings is not a sexual character. 



NOTES ON SOME OF THE GENERA OF MR. SCUDDER'S 



" SYSTEMATIC REVISION." 



BY THEODORE L. MEAD, CORNELL UNIVERSITY, ITHACA, N. Y. 



After reading Mr. Peabody's paper in the August number of the 

 Canadian Entomologist, I determined to verify some of the measure- 

 ments given as characterizing Mr. Scudder's genera, as it seemed hardly 

 possible that many of the numerical relations there given should prove 

 absolutely constant ; and after examining a large number of species and 

 specimens, these relations proved variable beyond all expectation. The 

 measurements of the venation were taken directly from the wings by the 

 aid of a thin sheet of transparent gelatine ruled with lines -h of an inch 

 apart, the wings having been bleached by Mr. Dimmock's admirable 

 process. 



Recently I have carefully gone over the measurements of the same 

 specimens, of the groups Lycaeides, Glaucopsyche and Cyaniris, with a 

 microscope, measuring by means of an eye-piece micrometer and 

 mechanical stage to the nearest thousandth of an inch, and find that the 

 former measurements coincide sufficiently with these to warrant confidence 

 in accepting the remainder as substantially correct. 



The results prove that the venation of the wing is very variable even 

 in specimens of the same species, and that no generic distinctions what- 

 ever can be based on slight differences in the proportionate length of the 

 cell and wing, or the origin of the first and second branches of the sub- 

 costal nervures of primaries. 



I have reduced the proportions of these parts mentioned by Mr. 

 Scudder to percentages, so that comparison will be easy. The species 



