250 Dr. Frederick A. Dixey on the 
markings to be found throughout the group, and have 
then attempted to state the phylogenetic conclusions to 
which this evidence appears to lead. Though my 
principal aim has been the elucidation of the Pierine 
wing-markings, which so far as | am aware have never 
before been systematically studied from this point of 
view, I have not ignored those other features that are 
usually known as “ structural” ; and I have also tried to 
estimate the bearing upon phylogenetic questions of the 
facts relating to the present distribution of the Pierinx 
in space. ‘lhe serious limitations under which anyone 
who wishes to construct a phylogeny for such a group as 
this must necessarily labour have been elsewhere acknow- 
ledged; it is of course manifest that little or no help 
can be expected from embryological or paleontological 
sources. ‘There are, however, many compensating features 
to be reckoned on the other side; and in view of certain 
comments that have at times been passed on previous 
work of this kind, I may perhaps be allowed to quote a 
few sentences from the writings of one of our leading 
naturalists, which seem to me to state the special ad- 
vantages afforded by these and similar researches with 
a force and cogency that it would not be easy to gainsay. 
After pointing out the pre-eminent value of the Diurnal 
Lepidoptera to the student of distribution and variation, 
the writer I refer to proceeds as follows—‘‘ But besides 
their abundance, their universal distribution, and the great 
attention that has been paid to them, these insects have 
other qualities that especially adapt them to elucidate the 
branches of inquiry already alluded to. ‘These are the 
immense development and peculiar structure of the wings, 
which not only vary in form more than those of any other 
insects, but offer on both surfaces an endless variety of 
pattern, colouring, and texture. . . . This delicately 
painted surface acts as a register of the minutest differ- 
ences of organization,—a shade of colour, an additional 
streak or spot, a slight modification of outline continually 
recurring with the greatest regularity and fixity, while the 
body and all its other members exhibit no appreciable 
change. The wings of butterflies, as Mr. Bates has well 
put it,* ‘serve as a tablet on which Nature writes the 
* See “The Naturalist on the Amazons,” 2nd edit., p. 412. 
