sept. 1896j Skinner: Study of N. American Butterflies. 113 
considered tentative only, and when the intervening gradational forms 
are found the true value of the new form should be recognized. The 
trouble with which we have to contend in such cases is that if we revise 
the work of others we are very apt to make them our enemies, and un¬ 
pleasant controversies arise. 
It has been said that there is no such species as Papilio ajax but the 
forms walshii , abbotii , telamonides and marcellus , which together make 
the species ajax. I do not object to this so long as the relationship is 
made apparent, but I would consider it entirely wrong to list these as 
distinct or specific names. The fault I find with our lists is that there 
is no exact comparative value among our so-called species. In one in¬ 
stance relationship may be thus indicated, and in other cases parallel 
value or relationship has not been so recognized. 
I now propose to take a glance at our species and give some opin¬ 
ions as to their comparative value. I do not say that my ideas always 
represent exact facts, but I think they will incline toward the truth and 
indicate what lines of study may be taken up in this contention. I do 
not mean to be hypercritical toward the work of our American students, 
as their work equals that done in any part of the globe. Moreover I do 
not see how any one can suppose that the naming of a new species indi¬ 
cates the value for all time, as names are only tentative until proven ab¬ 
solute, as far as the doctrine of evolution will allow. 
In our own country we have the wonderful effect of vertical dis¬ 
tribution, seasonal changes, differences of soil, climate, food, geology 
and, in fact, everything which suggests itself in this connection. In 
the genus Papilio we have twenty-six named as entitled to specific rank. 
Of these twenty-six nine are of doubtful value in varying degrees and I 
would arrange them thus, Ihoas, pergamus , hollandii , brucei , nezahual- 
coyotl , oregonia, nitra , rutulus , brevicauda , those of least value being 
mentioned first and the rest following in order given. Thoas is a 
synonym of cresphontes , pergamus of indra . Rutulus is probably a 
horizontal race of turnus , and was described as such by its author 
Boisduval. I have a specimen of Papilio taken here (Philadelphia) that 
would pass as rutulus . I believe a sufficient number of specimens of 
turnus and rutulus representing geographical distribution would prove 
their identity. I may say right here that I believe the imago the cul¬ 
mination of nature’s effort, and that while studies of transformation are 
most valuable they will not solve the problem of specific difference or 
identity. It would take too much space to go into details in regard to 
all these, and I will only give opinions in most instances. Brevicauda 
