( ivity 
of Butterflies, which was, as far as it went, quite in accord- 
ance with the facts then known, but is now somewhat out of 
date; and, moreover, errs in this respect, that many of the 
genera mentioned as characteristic are, from my point of 
view, not truly so. For I cannot regard as characteristic 
forms, genera which are not present throughout the greater 
part of the regions which they belong to, or which are found 
in equal abundance in other regions; but rather I consider 
those as characteristic which are dominant in number of species, 
found almost everywhere in these regions, and not in others, 
except in isolated cases or as stragglers. 
Dr. Adalbert Seitz has written a long and interesting paper 
in the Zoologischer Jahrbucher of Jena, vol. v., pp. 281— 
348, on the ‘Geographical Distribution of Butterflies and 
its Dependence on Climatic Influences,’ in which he at- 
tempts, inter alia, to show that the influence of trade winds 
has largely contributed to the abundance and variety of 
Lepidoptera in various parts of the world, and, so far as 
trade winds have affected the abundance or scarcity of vege- 
tation, there is no doubt some truth in this; but this 
theory is utterly insufficient to account for many of the most 
remarkable features we meet with; and though it is easy 
to find facts to prove almost any theory in such investigations 
as this, yet Dr. Seitz’s knowledge of many of the faunas 
which he mentions in proof of his theory is evidently very 
slight. He attributes to the influence of trade winds a fact 
which is only partially true, viz., that islands lying in the path 
of trade winds eastward of continents, such as Cuba, Mada- 
gascar, the Philippines, Borneo, and Formosa, are all very 
rich in insects, whilst islands lying to the west of conti- 
nents out of the course of a trade wind, are usually poor in 
insects. 
He ignores the difference between oceanic islands sur- 
rounded by deep seas which have probably been long isolated, 
and continental islands surrounded by shallow seas which in 
former ages were probably connected with continents. 
I am myself disposed to consider that the influences which 
contribute principally to the development of a large number 
of species and individuals of Rhopalocera, are largely climatic. 
