IJKI 



XIV. On the Species of Calocampa 



]iV 11. K. MOKllIhON, CA.MBItlDCK, MASS. 

 [Rend before this Society, Oct. 10, 1874. J 



Recently, in compiiring our species of this genus with their 

 European analogues, we were surprised to find that the form whicli 

 authors had considered identical with the European vetusta was, in 

 fact, quite different from it. More extended collections, and ex- 

 amination of material, also brought to light another intermediate 

 American species, between vetusta and cxoleta, and which can stand 

 as our representative of the latter. Specimens of solidaginis from 

 both countries w^re likewise compared, and diflferences were found, 

 apparently sufficient to authorize a specific separation. 



It will perhaps seem to many, tliat the cause of the constant 

 diminution, one by one, of the species Avhich have been thought 

 common to the two continents, is to be found rather in the desire 

 of the specialist to father new names than in the discovery of suf- 

 ficient and constant differentiating characters. ' But in most of the 

 recent separations, as Acronyda occideutaUs from j^si, CucuUia 

 intermedia from umhratica, and 3Iamestra atlantica from 11- 

 latinum, the diflfering characters are so invariable that if the species 

 lived side by side they would be considered distinct. This is the 

 only true test; and in this paper the author has endeavored to 

 apply it. 



CALOCAMPA, Steph. 

 Vetnsta Hnhner. Ilnh., Europe. 



Nnpera Lintner* 



This species fills with us the place of vetusta, and closely resem- 

 bles it\ A comparative description is therefore only necessary : 



* Since this paper was written I liave learned that Mr. J. A. Lintner has come to the same 

 conclusion in respect to Cal. vetusta and its American analogue as myself. I am indebted to 

 Mr. Grote for the opportunity of examining one of Mr. LintnerV typical specimens. 



