242 DIFFICULTIES OF THE THEOEY [Chap. VI. 



ingenious man, if he had not witnessed what takes 

 place, could never have imagined what purpose all 

 these parts serve. But Dr. Cruger saw crowds of large 

 humble-bees visiting the gigantic flowers of this orchid, 

 not in order to suck nectar, but to gnaw off the ridges 

 within the chamber above the bucket; in doing this 

 they frequently pushed each other into the bucket, and 

 their wings being thus wetted they could not fly away, 

 but were compelled to crawl out through the passage 

 formed by the spout or overflow. Dr. Cruger saw a 

 " continual procession " of bees thus crawling out of 

 their involuntary bath. The passage is narrow, and is 

 roofed over by the column, so that a bee, in forcing its 

 way out, first rubs its back against the viscid stigma 

 and then against the viscid glands of the pollen-masses. 

 The pollen-masses are thus glued to the back of the bee 

 which first happens to crawl out through the passage of 

 a lately expanded flower, and are thus carried away. 

 Dr. Cruger sent me a flower in spirits of wine, with a 

 bee which he had killed before it had quite crawled out 

 with a pollen-mass still fastened to its back. When the 

 bee, thus provided, flies to another flower, or to the 

 same flower a second time, and is pushed by its 

 comrades into the bucket and then crawls out by the 

 passage, the pollen-mass necessarily comes first into 

 contact with the viscid stigma, and adheres to it, and 

 the flower is fertilised. Now at last we see the full 

 use of every part of the flower, of the water-secreting 

 horns, of the bucket half full of water, which prevents 

 the bees from flying away, and forces them to crawl 

 out through the spout, and rub against the properly 

 placed viscid pollen-masses and the viscid stigma. 

 The construction of the flower in another closely 



