Mr. C. Darwin on the Ftrt'dization of Orchids. 9 



do tliis ; tliey always clung, wliilst sucking the nectar, to the 

 distal and hinged half of the lahelium, which was thus pressed 

 do\ynwards. Owing to this part being elastic and tending to 

 spring up, the bees, as they left the flowers, seemed to fly 

 rather upwards ; and this would favour, in the manner explained 

 by me, the complete withdrawal of the pollen-masses, quite as 

 well as an insect crawling out of the flower in an upward 

 direction. Perhaps, however, this upward movement may not 

 be so necessary as I had supposed; for, judging from the point 

 at which tJie pollen-masses were attached to the bees, the 

 back part of tlie head would press against, and thus lift up, the 

 blunt, solid, upper end of tlie anther, thus freeing the pollen- 

 masses. 



Various other insects besides hive-bees visit this Epqiactiti. 

 My son saw several large flies {Sarcojdiaga carnosa) haunting 

 tiie flowcTS ,• but they did not enter in so neat and regular a 

 manner as the hive-bees ; nevertheless two had pollen-masses 

 attached to their foreheads. Several smaller flies [Coslopa 

 friffida) were also seen entering and leaving the flowers, with 

 pollen-masses adliering rather irregularly to the dorsal surface 

 of the thorax. Three or four distinct kinds of Ilymenoptera 

 (one of small size being Grahro hrevis) likewise visited the 

 flowers ; and three of these Ilymenoptera had pollen-masses 

 attached to their backs. Other still more miimte Diptera, 

 Coleoptera, and ants were seen sucking the nectar ; but these 

 insects appeared to bo too small to transport the pollen-masses. 

 It is remarkable that some of the foregoing insects should 

 visit these flowers ; for Mr. F. Walker informs me that the 

 Sarcophaga frequents decaying animal matter, and the Gwlopa 

 haunts seaweed, occasionally settling on flowers ; the Cral/ro 

 also, as I hear from Mr. F. Snnth, collects small beetles (//«/- 

 ticce) for provisioning its nest. It is equally remarkable, see- 

 ing how many kinds of insects visit this EpijxtctiSj that, al- 

 though my son watched for some hours on three occasions 

 hundreds of plajits, not a single humble-bee alighted on a 

 flower, though many were flying about. In a footnote I have 

 given the results of experiments made by Mr. More, by cutting 

 oflf the distal and hinged half of the labellum, in order to as- 

 certain how far this part is important. lie has now repeated 

 the experiment on nine additional flowers : of these, three did 

 not produce seed-capsules; but this may have been accidental. 

 Of six capsules which were produced, two contained about as 

 many seeds as the capsules of unmutilated flowers on the same 

 jdant; but four capsules contained much fewer seeds. The 

 seeds themselves were well-formed. These experiments, as 

 far as they go, support the view that the distal part of the 



