ry that the
nectar is secreted on the outside of the calyx. See "Nature," July 2nd,
1874, page 169; also Letter 715.) This will in every way be far better
than writing to Delpino. It would not be at all presumptuous in you to
criticise Delpino. I am glad you think him so clever; for so it struck
me.

Look at hind legs yourself of some humble and hive-bees; in former take
a very big individual (if any can be found) for these are the females,
the males being smaller, and they have no pollen-collecting apparatus.
I do not remember where it is figured--probably in Kirby & Spence--but
actual inspection better...

Please do not return any of my books until all are finished, and do not
hurry.

I feel certain you will make fine discoveries.

LETTER 709. TO T.H. FARRER. (Lord Farrer). Sevenoaks, October 13th,
1872.

I must send you a line to say how extremely good your article appears to
me to be. It is even better than I thought, and I remember thinking it
very good. I am particularly glad of the excellent summary of evidence
about the common pea, as it will do for me hereafter to quote; nocturnal
insects will not do. I suspect that the aboriginal parent had bluish
flowers. I have seen several times bees visiting common and sweet
peas, and yet varieties, purposely grown close together, hardly ever
intercross. This is a point which for years has half driven me mad,
and I have discussed it in my "Var. of Animals and Plants under Dom."
(709/1. In the second edition (1875) of the "Variation of Animals and
Plants," Volume I., page 348, Darwin added, with respect to the rarity
of spontaneous crosses in Pisum: "I have reason to believe that this
is due to their stignas being prematurely fertilised in this country
by pollen from the same flower." This explanation is, we think, almost
certainly applicable to Lathyrus odoratus, though in Darwin's latest
publication on the subject he gives reasons to the contrary. See "Cross
and Self-Fertilisation," page 156, where the problem is left unsolved.
Compare Letter 714 to Delpino. In "Life and Letters," III., page 261,
the absence of cross-fertilisation is explained as due to want of
perfect adaptation between the pea and our native insects. This is
Hermann Muller's view: see his "Fertilisation of Flowers," page 214.
See Letter 583, note.) I now suspect (and I wish I had strength to
experimentise next spring) that from changed climate both species
are prematurely fertilised, and theref