Cjje dfenabian ^domobgist. 



VOL. VIII. LONDON, ONT., FEBRUARY, 1876. No. 



THE NORTH AMERICAN ULUE BUTTERFLIES OF THE 



GENUS NOMIADES. 



BY SAMUEL H. SCUDPER, CAMBRIDGE, .MASS. 



Some years ago I proposed* the generic name Glaucopsyche for a 

 group of blue butterflies of eastern N. America having a glaucous sheen 

 to the upper surface of their wings : I had not then recognized its strictly 

 generic alliance with a group of similar forms in Europe and on our Pacific 

 slope, which do not all possess this peculiarity, and to which the older 

 generic name Nomiades Hiibn. must be applied. A recent study of their 

 common structural features, however, shows that Glaucopsyche can no 

 longer be retained. Finding that there has been some confusion, at least 

 in the cabinet designations of the species of this group, a brief revision 

 of the same, with comparative descriptions, is here offered 



The species belonging to this group, it may be remarked, all have but 

 a single transverse series of spots upon the under surface of the hind 

 wings (the extra-mesial row), the submarginal markings being wholly 

 obsolete. In the six American species the upper surface of the wings of 

 the male are always blue, more or less broadly and distinctly margined 

 with dark brown, while the wings of the female have this surface dark 

 brown, more or less amply suffused from the base outward with blue. 



1. X. Xerces (Lycceua Xerces Boisd.) In this species the blue on 

 the upper surface of the wings of the male is of a pale tender violet and 

 the margin is neither so black nor so narrow as in the other species, and 

 has a very faint extreme edge of black. The upper surface of the wings 

 of the female is of a little paler brown than in the other species, has a 

 decidedly white, untarnished fringe, and at the base scattered blue scales 

 as in A. Antiacis. but extending further from the base ; the black outer 

 edge is more distinct than in the female of the other species. Beneath, 



Syst. Rev. Am. Butt., 33. 



