516 THE CURIOUS HISTURY OF A BUTTERFLY. 
as yet unprepared to say; but that the blood of both series ever : 
commingles, through the union of the perfect insect, is very improb- 
able because, although the generations overlap, the males-of a 
brood are the first to disappear and the females the last to appear, 
and at best there would be few that could thus mate; moreover, 
since the eggs of the freshly enclosed females are not fully devel- A 
oped for weeks, or even months, the effect of such a union would 
be questionable. Yet, if there is no union between the two series, l 
there are the vernal and æstival groups practically as distinct . 
from each other as any two species! Nature strives toward the 
formation of a double brood in the vernal series; may We not 
suggest that she has already made considerable progress toward 
the development of a new species, in producing the vernal series 
at all? Pass in review ‘the histories of different species of the 
and you will find 
same genus or even allied genera of butterflies, , 
in them a remarkable similarity — trace of a law of unity in habits 
and seasons as pronotinced as that of unity in coloration and 
structure, extending not only to the number of broods, but also 
to their seasons. In the æstival series of Brenthis we find iD : 
something very similar to what occurs in „Argynnis, and this m 
therefore be considered the normal series ; but, in addition, we have 
. a second set of individuals maintaining a totally distinct a 
by other means (lethargy or premature hibernation), passmg * 
winter in a different condition, and even attempting an ad o 
generation — showing a difference such as usually m 
somewhat distant genera. Will not Messrs. Cope pae i 
claim this as a new argument in favor of their theories of the a 
gin of species? eo 
Whether any colorational or structural features distinguish ue 
butterflies of the vernal from those of the æs al 
unable to say and must leave to those who can follow pat? 
in the field; it is a question worthy of investiga eee 
spring and autumn broods of butterflies often present OY 
- so well marked that the broods have been described wae : 
species. ye : 
` Some one will ask whether these different apparitione ie 
butterfly cannot be accounted for on the supposition 
series of individuals, with lethargy on the part of the 7 or 
as in the case of the European Euphrosyne. Plainly 2° alk y 
have in our butterfly three apparitions instead of tWOr' 
