Phylogeny of the Pierinee. 289 
Hesperocharis, we find it become tolerably evident 
that the dark yellow vestige which at last alone 
remains is the result of a kind of convergence both in 
colour and position of the yellow and red markings that 
at first lie simply side by side and are clearly dis- 
tinguishable the one from the other.* A further instance 
of possible convergence is supplied by the basal pinkish 
patch, found in the group of genera headed by Colias, 
which we have seen reason to identify with original 
markings of both the red and yellow kinds.+ In other 
cases, the persistence of various members of the present 
system is determined by the exigencies of a mimetic 
pattern, as in the species of Mylothris and Hesperocharis 
above referred to (p. 286). 
III. Pasytogenetic ConcLusions. 
1. The evidence of the Wing-markings. 
We are now in a position to consider as a whole the 
various sets of facts that have been above recounted, 
and to endeavour to construct, from the evidence at 
hand, a theory of the phylogenetic history of the entire 
group. This, of course, is only attempted under the 
* This, it is true, applies only or mainly to the New World 
forms ; the similar basal red patch that partly occupies the pre- 
costal space in certain species of Delias and Prioneris not seeming 
to have left any traces in those Old World genera (Belenois and 
T'eracolus), which appear to stand in much the same relation to 
Delias and Prioneris as Pieris and Hesperocharis do to Leodontu 
and Catasticta. 'The deep orange, however, of the precostal streak 
in some Old World species of Mylothris (as M. chloris and M. 
agathina), and in some species of Belenots (as B. helcida) which 
resemble them, may perhaps be derived wholly or in part from the 
precostal red ; but if so, it does not bear in itself a plain record of 
its origin as does the like feature in the corresponding genera from 
America. 
+ Again, in Pieris pylotis the only marking to be seen on the 
under surface of the hindwing (besides the basal spot) is a short and 
narrow orange streak near the apex of the median interspace— 
an interspace that in more primitive forms, such as P. locusta, 
Mylothris lypera, and others, is provided with an apical red patch. 
It is also worthy of notice that in many species of Belenois the 
spots of series I are apt to retain or assume an unusually deep yellow 
or orange colouring like that of the precostal streak—this series 
being in some species of Delias, and at least one of Prioneris, a 
sharer in the bright red of the basal patches (see p. 284). 
