io6 OUR NATIVE ORCHIDS 



been removed the anther sprang back a little, and the 

 rostellum bent its tip so that it hung directly over the lip- 

 Once he found an injured flov^er in which this had not 

 occurred, and the tip of the anther had become glued fast ta 

 the rostellum, so that the pollen masses were hopelessly- 

 locked between the two. 



Having observed that nectar was secreted copiously 

 along the ridge of the lip above its split end, Darwin went 

 out to see whether the insects worked in the way that his 

 constructive imagination had led him to believe. He 

 says: "In order to witness what I felt sure would take 

 place, I watched for an hour a group of plants on three 

 occasions; each time I saw numerous specimens of twa 

 small Hymenopterous insects, namely, a Hsemiteles and a 

 Cryptus, flying about the plants and licking up the nectar; 

 most of the flowers which were visited over and over again 

 already had their pollinia removed, but at last I saw both 

 these species crawl into younger flowers, and suddenly 

 retreat with a pair of bright yellow pollinia sticking to their 

 foreheads. I caught them and found the point of attachment 

 was to the inner edge of the eye; on the other eye of one 

 specimen was a ball of the hardened viscid matter, showing 

 that it had previously removed another pair of pollinia, and 

 in all probability had left them on the stigma of a 

 flower." 



As Darwin captured these insects he could not con- 

 scientiously say that he saw the act of fertilisation, but he 

 quotes Sprengel, who saw a Hymenopterous insect leave 



