1900. } GROTE—THE DESCENT OF THE PIERIDS. 59 
the embryonal wing, these do not abrogate the differences in the 
imaginal. These exist in the present instance, throwing the com- 
mon origin of the two groups further back, and render the supposi- 
tion tenable, that the Papilionides and Hesperiades, as butter- 
flies, have a different origin. The conclusion to which I have come 
is this, that all the groups of the Hesperiades converge in ancestral 
types of the Skippers, to the entire exclusion of the Papilionides. 
Objections will be made that the Skippers are so different from 
other butterflies. I have tried to show that these differences arise 
from secondary specializations and are not constant or peculiar. 
From a bend in the antennz, classificators give such names as 
‘“ Grypocera.’’ But how about those Skippers which lack the bend ? 
Are these, too, ‘‘ Grypocera’’? Again, some writers dwell with 
astonishment upon the fact that certain Skippers like to stroll in the 
dusk of evening, and these writers hold that, with such habits, these 
Skippers cannot be considered as orthodox diurnals. And then a 
special name is coined for them as a sort of atonement for heresy. 
But clearly all this arises from preconceived opinions, from want of 
consideration and weighing of characters. No value is given by 
these classificators to the exceptions which deprive their catego- 
ries of proper support. All the characters shown by the Skippers 
are explainable by the fact that we have to do witha group originally 
transitional in habit and structure, and having become a fixed and 
natural one through custom. 
THE EVIDENCE FROM FossIL BUTTERFLIES. 
The evidence from paleontology is so scant that of itself it can 
have no deciding weight. One feature, however, which assists my 
ideas is that the tertiary deposits have yielded a larger proportion of 
Nymphalids. We might naturally expect, among the Hesperiades, 
that the groups in which the radius is specialized, viz., the Pierids 
and the Blues, would be more recent, succeeding in point of time the 
Skippers and the Nymphalids. I think we may assume the fact. Ina 
recent valuable paper by Dr. Rebel, a restoration is given of the wing 
of Lycenites. This is a presumed lycznid, and there is no improba- 
bility in the view that the Blues may have been represented in the 
Miocene. But I wish to point out that a slight change in the restored 
wing parts would give us the Skipper type, in this case apparently one 
resembling the North American Megathymidz, a group with general- 
ized larvee, and which may also have enjoyed a greater range and rep- 
