A at 
ET. 52.] TO CHARLES DARWIN. 509 
It is pretty to see honey-bees cross-fertilize Lo- 
cust (Robinia), much as you say of broom. One of 
my students has been noticing the way bees act on 
Kalmia. 
Now for my best thing for to-day. 
An orchid which I missed last year, Platanthera 
flava, I knew would be curious, for I remembered a 
strong protuberance on base of labellum, on the me- 
dian line. I have not time left to describe it now, hav- 
ing been sadly interrupted, but it is pretty, — equal to 
anything you have yet seen in British orchids. The 
process turns proboscis of insect either to right or left, 
where it will slip into an imperfect ring (as seen from 
above) or deep groove (as seen from before), in which 
lies the disk, not flat but coiled up, ready to catch pro- 
boscis. It is like the eye of a needle to receive the 
thread. 
Perhaps I will send you, or print, a sketch! of the 
thin 
ng. 
I am waiting for Gymnadenia tridentata to come 
on 
But the post hour has come. 
July 21. 
Your latest is of the 26th ult. You need not 
worry! It never wearies nor bores me to write to 
you, in the off-hand way I do. I enjoy our corre- 
spondence too much to consent to curtail or interrupt 
it. I learn from you, here in this remote part of the 
world, a thousand things which I should not other- 
wise know at all. And you stimulate my mind far 
more than any one else, except, perhaps, Hooker. So 
please do not make a fuss, but let me go on in my own 
1 There was a rough sketch of the disk, ete., in the margin. 
