156 Alexander Goodman More. [i860 



first week of March, and again Epipactis palustris was the 

 principal topic. "The examination of that species has 

 been one of my greatest treats, which I owe to you," 

 Mr. Darwin wrote (June 2nd, 1861). "I hope that you will 

 be so kind as to observe manner of ingress and egress of 

 insects if you can see any visit the flowers, and whether 

 labellum is irritable. I fear I may be unreasonable, but 

 this subject is a passion with me." 



This letter was followed, two days later, by the follow- 

 ing memorandum of instructions for watching the plant: 



EPIPACTIS PALUSTRIS. 



(1) When an insect visits this flower, does it alight on the labellum? 

 And in entering the flower, does it depress the terminal portion, and 

 does this spring up again after the insect has entered ? 



(2) Especially when the insect departs, does it crawl back by the 

 Labellum, or does it crawl out at the top of the flower ? 



(3) If you see one crawl out, please observe whether the yellow 

 pollen-masses are sticking to its head or back : this would occur only 

 in a lately opened flower. Observe whether it enters another flower, 

 and whether it does not there leave the pollen-masses sticking to the 

 stigma, or at least some of the yellow pollen -grains, which would be 

 easily visible. 



(4) What kind of insect visits these flowers ? If you should see 

 several, please catch one by crushing flower in which it is, and send it. 



(5) As the labellum in some foreign orchids is irritable, tickle on 

 calm day with bit of grass the middle part of labellum near the joint 

 of terminal part, and see whether it excites any movement, slow or 

 quick. 



If by any extraordinary chance the labellum should be irritable, 

 will you observe carefully what part must be touched ? 



The concluding questions were readily answered, as 

 Mr. More found no trace of irritability in the tickled flower. 

 But the watch for insects proved disappointing : they 

 would not come. Failing direct observation, Mr. Darwin 

 next asked him (July yth) to " try a little experiment, 

 viz. to cut off the terminal and moveable division of the 

 labellum in six or eight flowers which had not quite 

 opened, and which therefore could not have been visited 

 by insects ; and mark these flowers with little bits of 

 thread ; and then see if these set pods as well as the other 

 flowers." " I would not (he added) on any account have 



