column?--here insects alight and are beautifully shot, when they touch a
certain sensitive point, by the pollinia.

How kindly you have helped me in my work! Farewell, my dear old fellow.

LETTER 137. TO H.W. BATES. Down, May 4th [1862].

Hearty thanks for your most interesting letter and three very valuable
extracts. I am very glad that you have been looking at the South
Temperate insects. I wish that the materials in the British Museum had
been richer; but I should think the case of the South American Carabi,
supported by some other case, would be worth a paper. To us who theorise
I am sure the case is very important. Do the South American Carabi
differ more from the other species than do, for instance, the Siberian
and European and North American and Himalayan (if the genus exists
there)? If they do, I entirely agree with you that the difference would
be too great to account for by the recent Glacial period. I agree, also,
with you in utterly rejecting an independent origin for these Carabi.
There is a difficulty, as far as I know, in our ignorance whether
insects change quickly in time; you could judge of this by knowing how
far closely allied coleoptera generally have much restricted ranges,
for this almost implies rapid change. What a curious case is offered by
land-shells, which become modified in every sub-district, and have yet
retained the same general structure from very remote geological periods!
When working at the Glacial period, I remember feeling much surprised
how few birds, no mammals, and very few sea-mollusca seemed to have
crossed, or deeply entered, the inter-tropical regions during the cold
period. Insects, from all you say, seem to come under the same category.
Plants seem to migrate more readily than animals. Do not underrate the
length of Glacial period: Forbes used to argue that it was equivalent to
the whole of the Pleistocene period in the warmer latitudes. I believe,
with you, that we shall be driven to an older Glacial period.

I am very sorry to hear about the British Museum; it would be hopeless
to contend against any one supported by Owen. Perhaps another chance
might occur before very long. How would it be to speak to Owen as soon
as your own mind is made up? From what I have heard, since talking to
you, I fear the strongest personal interest with a Minister is requisite
for a pension.

Farewell, and may success attend the acerrimo pro-pugnatori.

P.S. I deeply wish you could