sept. 1896.] Skinner: Study of N. American Butterflies. 107 
mint Valley, Cal. I have also seen specimens from Mexico (Sumi- 
chrast), near Mescico, Mex. (Palmer), and from Jalapa, Orizaba and 
Menanitlan, Mex. (L. Bruner). 
Nemobius carolinus. 
Nemobius carolinus Scudder ! Proc. Bost. Soc. Nat. Hist. XIX, 36 (1877). 
Cyrtoo^iphus variegatus Bruner ! Publ. Nebr. Acad. Sc. Ill, 32 (1893). 
Nemobius affinis Beutenmuller ! Bull. Amer. Mus. Nat. Hist. VI, 249, 
267, PL 5, fig. 11 (1894). 
No macropterous form is known. There is considerable variation, 
apparently independent of locality, in the fineness of the denticulation 
of the blades of the ovipositor. 
Specimens before me come from Jackman, Me. (Harvey—A. P. 
Morse), Norway, Me. (Smith—Mus. Comp. Zook), Blue Hill, Milton, 
Mass. Sept. (S. Henshaw), Adams, Mass. (Morse), South Kent and 
Canaan, Conn., (Morse), New York (Beutenmuller), Ithaca, N. Y. 
(Morse), Orange, N. J., (Beutenmuller), Maryland (Uhler), Vigo Co., 
Ind. (Blatchley), District of Columbia and Virginia (Bruner), North 
Carolina (Morrison, Henshaw), Lake Worth, Fla. (Mrs. Slosson), 
Lake Okeechobee, Fla. Palmer), New Orleans, La , (Shufeldt—U. S. 
Nat. Mus.), Texas (Boll), Texas “ Flying to light” (Belfrage), Lin¬ 
coln, West Point and South Bend, Nebr. (Bruner). 
IMPRESSIONS RECEIVED FROM A STUDY OF OUR 
NORTH AMERICAN RHOPALOCERA. 
By Henry Skinner, M. D. 
I wish to speak of specific values—a subject which has always agi¬ 
tated the scientific mind, and perhaps always will in the future. My 
excuse for writing on such a subject is the fact that I believe the proper 
kind of studies will enable us to approximate an absolute specific value, 
or at least get much nearer the truth than is now shown by a study of 
our catalogues and lists of species. I do not care to go into the trite 
subject as to what is a species, but think it only fair to give my own 
view, or that which I should follow in the rearrangement of our species. 
I look upon the species as the unit of classification, and therefore it is 
all important to have the basis of classification as scientifically accurate 
as possible. I would divide the definition of species into two heads: 
