WINGLESS INSECTS 449 
marshes of N.S. Wales and Tasmania, but is not found wild 
elsewhere out of Europe that I know of in the Southern 
Hemisphere — these are the extraordinary facts that will 
not be accounted for. Out of full 800 species I do not 
think that there are a dozen common to South-East and 
South- West Australia ; whole well marked genera, containing 
many sections and species, are absolutely confined to S.W. 
Australia. There is nothing like this in any other part 
of the world : it is utterly astounding, and though I thought 
myself well up in the Austrahan Flora, I was not prepared 
for this to such an extent. Also taken as a whole the Flora 
of Tasmania does not present so many species hardly distinct 
from S.E. Australia as it ought. The Tasmanian species are 
either very distinct, or quite the same, and what is most 
curious, this applies as well to the alpine plants, though the 
climate of the Australian Alps must be a good deal different 
from that of the Tasmanian ones. 
There is another point to be worked in your apterous 
insect case — viz., the proportion of apterous European species 
in Madeira great or small. If over-sea migration were the 
means of peopling Madeira with insects, then the European 
species should be winged ones. There is still another point. 
Do you suppose that the majority are apterous because the 
winged ones have been blown out to sea and perished 
miserably ? Eeally these questions are like Cerberus and 
his heads — the more arguments one disposes of the more 
rise up in your way. 
Kew : November 9, 1856. 
I have finished the reading of your MS. [on Geog. Distrib.] 
and have been very much delighted and instructed. Your 
case is a most strong one and gives me a much higher idea 
of change than I had previously entertained ; and though, 
as you know, never very stubborn about unalterability of 
specific type, I never felt so shaky about species before. The 
first half you will be able to put more clearly when you pohsh 
up. I have in several cases made pencil alterations in details 
as to words, &c., to enable myself to follow better — some of 
it is rather stiff reading. I have a page or two of notes for 
discussion, many of which were answered as I got further 
with the MS., more or less fully. 
Your doctrine of the coohng of the tropics is a starthng 
