46 



My attention was especially drawn to the present subject by discovering in June 

 1882, a dipterous fly imprisoned in the large yellow lip of a plant of C. pubescens, which 

 I had under cultivation. The insect either had been attracted by the sweet odour or had 

 resorted to the flower as a convenient shelter on the previous evening, but had not been 

 able to get out again. It never attempted to escape by the wide opening above ; for 

 hours it strove to force its way under the column, but being too large to pass beneath the 

 stigma, it always fell back into the cavity of the lip. On the next day, the fly was still 

 in its trap, but motionless. I supposed it was exhausted and took it out, but it flew away 

 immediately. 



I then placed into the same flower a smaller fly which very soon disappeared under 

 the staminodes and arrived at one of the posterior openings. There, however, it could 

 pass only its head : the glutinous pollen of the anther held it fast by the thorax and all 

 its efforts to regain its liberty were useless. As the flower matures, the pollen becomes 

 less cohering and the tissues of the lip less rigid ; the insect might have been thus released, 

 but I took upon myself to do the work. I had some difficulty, as I wished to injure 

 neither the insect nor the flower. I then noticed how rigid the edges of the lip is under 

 the aperture, and how it is further maintained in its position by the pointed tip of the 

 filament of the anther. 



Having disengaged the fly, I gave it its liberty, but carrying away a lump of pollen 

 firmly fixed on its thorax. It had not occurred to me that it might have been still of use 

 to me ; for, it was now easy to understand that if the insect with its thorax thus coated 

 with pollen had been placed in a flower, it could not fail to follow in it the same way and 

 to leave pollen on the stigma when passing under it, for the walls of the lip close on either 

 side so as to leave no passage but under .the stigmatic dis, which is beset with rigid 

 papillae evidently destined to retain the pollen. A smaller fly, however, was soon found, 

 I besmeared its thorax with pollen and placed it in the lip of a flower. I had the satis- 

 faction to see it nearly immediately come out at one of the back apertures, and without 

 difficulty as it was smaller, but, however, having fulfilled its mission and polliuised the 

 stigma. I may add here, that the flowers thus fertilised produced perfect capsules, though 

 I had never before obtained any on my cultivated plants, on account, no doubt, of the 

 absence in the city of the insects by which in a state of nature the flowers are usually visited. 

 I could not doubt that such must be the mode of fertilisation, though Darwin, in the 

 first edition of his work on the Fertilisation of Orchids published in 1862, expressed the 

 opinion that pollination was performed by some insect's long proboscis inserted through 

 the openings at the baek. And I found afterwards that the inadmissibility of that view 

 had been seen long ago by Prof. Gray, who first understood that insects must enter bodily 

 the flowers of Cypripedium and visiting several flowers in succession bring about cross- 

 fertilisation, (Journal of Science and Art, Nov. 1862). In 18G3, Prof. S. I. Smith, saw 

 some flowers of C spectabile almost covered by numbers of small flower-beetles, some of 

 which eventually pollinised the stigma. :|: Mr. J. Fletcher in 1884 observed also on the 

 same plant that same insect, which has been identified only last winter as being Antho- 

 bium convexum. Prof. Smith adds : " Of many flowers from different places, nearly all 

 had had the pollen removed in minute particles from the anther to the stigma ; but, in 

 two or three instances, the pollen had been removed in one mass as if by some large 

 insect." '"These observations have the peculiar interest of having probably been the first 

 made on this continent of the actual fertilisation of orchids. They also justified Prof. 

 Gray's theory, that the insects entered the flowers, but though self-fertilisation was 

 thus effected, crossing could scarcely ever occur, and the arrangement of the organs of the 

 flower is obviously destined as in other orchids to insure the transport of pollen to the 

 stigma of another, as in other orchids, and as had probably been the case in the three 

 instances mentioned by Prof. Smith, when he found large masses of pollen on stigmas. 

 In 1868 an observation of Dr. H. Miller on the Cypri/ tedium calceolus of Europe, con- 

 firmed definitively Prof. Gray's view : the German professor found in a flower a bee, 

 Andrena pratensis, and saw the plant fertilised by it and afterwards also by four other 

 species of the same genus, t 



* Proceedings of the Boston Soc. of Nat. Hist., Nov. 18G3. 

 t American Naturalist 1871, p. 285, and Midler's Fertilisation of flowers. 



