Phylogeny of the Pierinee. 269 
alone as a marginal band, showing more or less ten- 
dency towards resolution (Appias lyncida $, A. celes- 
tina 6, etc.). 
Summary.—The present, like the preceding series, is 
thus seen to be a relic of the original dark ground-colour. 
It is intercepted between the margin of the wing and 
a series of pale touches (best seen in certain species of 
Delias and Catasticta) that making their appearance in 
the submarginal region of the interspaces, more or less 
isolate, indent and divide up the dark marginal area. It 
may eventually disappear altogether (as in some speci- 
mens of G. rape 3), but usually persists on the forewing, 
at least, in the region of the apex. When present, it 
shows great variation in the extent to which it is resolved 
into separate spots, and also in the amount of fusion it 
undergoes with the neighbouring series 8. As a general 
rule it is, like the last-named series, more constantly 
present in the female sex, and more completely resolved 
in the male. 
3. The light series between 1 and 2. 
The region of pale ground-colour included between 
the two dark-coloured series S and M, becomes of 
necessity more sharply defined and circumscribed as the 
constituents of each dark series become fused together 
into bands instead of remaining as rows of spots. The 
tendency so often seen of the two dark series to become 
partially fused with one another, by the extension 
between them of dark lines following the course of the 
nervules, leads, when carried far enough, to the splitting 
up of the included pale area into a series of pale spots, 
which sometimes attain a very distinct and definite 
character, especially at the apex of the forewing. These 
pale spots have already been incidentally noticed during 
the discussion of the two series between which they lie ; 
it will not be necessary to do more in this place than to 
suggest that, for the purpose of separate reference, the 
letter I should be taken to represent the whole series, 
the possible constituents being numbered {—20, in corre- 
spondence with the dark spots of series S which bound 
them on the inner aspect. (See Figs. 1, 2, 5, 21, etc.) 
4, The discoidal spots. 
In none of our three common species of Ganoris does 
