324 Dr. Frederick A. Dixey on the 
sub-region, to which it no doubt made its way along the 
great mountain-chains in a similar manner. Its close 
ally, Baltia, remains in the high lands of Central Asia, 
where it bears much the same relation to Synchloe as 
Phulia to Tatochila. Another early offshoot from the 
Kastern Pontia stem is Mesapia peloria,* which has no 
representative in the Western Hemisphere. 
The above descendants of the mountain Metaporias 
belong, as has been seen, in the first place, to the 
Paleearctic and western portion of the Nearctic Region, 
only reaching the Neotropical by extension along the 
chain of the Andes. Other derivatives of Metaporia, 
however, took their course directly southwards. The 
first of these is the Delias and Prioneris group, the more 
ancient members of which are, speaking generally, to be 
found in the northern portion of the Indian peninsula, 
while the Australian and other southern forms represent, 
as a rule, a somewhat later stage of development. 
Another is the important branch headed by Hwphina, 
which genus, like Delias, has spread downwards through- 
out the Oriental Region, and by way of the Indo- 
Malayan and Austro-Malayan islands to the Australian 
continent. The Australian species of Hwphina are 
clearly derived from the Oriental, and those forms (such 
as H. phryne ?) which are nearest to M. agathon in 
colouring are also its closest neighbours geographically. 
Of the two genera (Hiposcritia and Catophaga) which 
appear to be immediately derived from Hwphina, the 
former is confined to the Oriental Region; while the 
latter, hke Huphina itself, has spread along the Austro- 
Malayan Islands to the Australian mainland. This is 
also the case with Appias,t the origin of which genus 
from the Catophaga stock is no doubt to be assigned to 
the Oriental’ Region. But, unlike the other genera, 
Appias seems to have extended its borders westwards, 
and to have given rise to the “ Phrissura B”{ group in 
the Ethiopian Region, and even to Glutophrissa in the 
Neotropical. If this be the real origin of these two 
latter genera, we have to enquire how they reached the 
African and South American continents respectively. 
* See p. 304, 
T It would seem, however, that no true Appias actually reaches 
the Australian continent. 
{ See p. 309, note. 
