326 Dr. Frederick A. Dixey on the 
of Mr. Spruce, who saw Callidryas “launching boldly 
out over the Pacific Ocean.’’* 
The earliest species of Synchloe were undoubtedly 
differentiated from Pontia or Baltia in the Palearctic 
Region, from which the genus spread (probably east- 
wards) into the Nearctic. Synchloe proper can hardly 
be said to enter the Indian Region,+ but in its progress 
westwards it has sent an offshoot downwards into the 
Ethiopian, consisting of S. johnston and S. hellica. 
S. glauconome of Arabia and Egypt remains to mark the 
course of the invasion. Ganoris, a further Palearctic 
development of Synchloe, has accompanied that genus 
into the Nearctic Region and has also spread into the 
Oriental. A curious extension of the range of the 
Palearctic G. rapx into the Nearctic Region has been in 
progress during the last thirty-three years, the first 
transatlantic specimens having been seen at Quebec in 
the year 1860.{ ‘This introduction was undoubtedly 
effected by human agency, and differs from the natural 
passage of species between the two Regions in having 
taken place by the Atlantic instead of the Pacific route. 
Though Synchloe itself is far more characteristic of 
temperate than of tropical districts, it has given rise to a 
large and important Pierine branch which has spread far 
and wide through tropical and temperate parts alike. 
The birthplace of Herpexnia and Teracolus, the two 
earliest members of this extensive section, is apparently 
the eastern portion of the Mediterranean division of the 
Palearctic Region; from which locality the former has 
spread through Arabia and Abyssinia into the African 
continent, while the latter has not only followed Herpenia 
into Africa, but has also largely occupied the two western 
Oriental sub-regions. Those forms of the genus Izias 
that show least divergence from Teracolus are found in 
the Nile provinces of Eastern Africa, but the bulk of this 
genus has moved eastwards, its distribution being 
characteristically Indian. A few species, however, are 
found in some of the Indo-Malayan islands, and in 
Austro-Malaya as far east as Timor. 
* Journal Linn. Soc., Zool., ix., pp. 355—357. 
+ See Wallace, Trans. Ent. Soc. Lond., 3rd series, iv., pp. 242, 3. 
+ Scudder, “Butterflies of the Eastern United States,” 1889, 
vol. i1., pp. 1175-1190 ; Edwards, “ Butterflies of North America,” 
vol. 1., 1868-72, sub. voc. P. virginiensis. 
