JET. 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 l of the 

 thing. 



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, etc., in the margin. ^ 



