26 [July 



yet described, but named in MS. by Boisduval N^nvadpiiais. Dr. Behr 

 says : "A few specimens of this new and as yet undescvibed C/nonobax 

 were caught by Mr. Lorquin, the discoverer of the species, and named 

 by Dr. Boisduval. Not possessing a single specimen of this rare spe- 

 cies, I am not able to give a diagnosis, and have only an indistinct recol- 

 lection, that the species bore most resemblance to the Gerontogeic C'l. 

 Tarpeja, a Siberian species that has also been found on the summit of 

 the Apennines, in Italy, but that in size it is superior to any Chio)iohas 

 known to me." 



Taking for granted that my views in regard to the distinction of the 

 species of this genus in North America are just, and that Moschler has 

 correctly stated the value of the differences he has noticed among those 

 of Europe, with the exception of his separation of the individuals be- 

 longing to C. Oeno into two species (^Oeno and Also), and admitting the 

 exactitude of his assertions — and those of many others — that several 

 species of the genus are common to the subarctic regions of either side 

 of the Atlantic — we must picture to ourselves the genus Chlonohas a^ 

 composed of butterflies of a sombre appearance nearly uniform in color- 

 ation upon their upper surface, beneath brightened by blackish and 

 and whitish contrasting colors, so arranged upon the secondaries as to 

 form a band crossing the middle of the wing, of varying width and 

 direction; the species inhabiting inhospitable regions, either (1) as far 

 toward the poles as where the snow lies upon the surface of the ground 

 by far the greater portion of the year, or (2) far above the limit of the 

 trees growing upon the sides of lofty mountains in the temperate re- 

 gions; and as to the geographical distribution of the species, either (1) 

 common to the arctic regions of both sides of the Atlantic, the indivi- 

 duals of each species compassing the same range and character of vari- 

 ation upon either side, some (a) found throughout the arctic regions 

 over a nearly continuous belt of country (6*. Jutta^ C Bore); others 

 (b) found at the extremes and not in the intermediate countries, such 

 as Greenland (C. Oeno); or (2) confined to the arctic regions of Eu- 

 rope and not found in America (T/. Norma, 0. Sculda, C. Tarpeja) or 

 (3) to the same regions of America and not found in Europe ( C. Calais). 

 or lastly (4) confined to the alpine districts of mountains rising in tem- 

 perate latitudes on either one or the other continent (Europe C. Aello ; 

 Eastern America 0. scmiJea ; Western America C. Chrt/xus). The 

 question then naturally arises, what relations of structure do the species 

 of these different localities and varying range of habitat bear to one 

 another? It has been asserted that species existing over a wide range 



