large upper opening," Darwin wrote, "but they were either too 

 large or too stupid, and did not crawl out properly. I then 

 caught and placed within the labellum a very small bee which 

 seemed of about the right size, namely Andrena parvula. . . . 

 The bee vainly endeavored to crawl out again the same way it 

 entered, but always fell backwards, owing to the margins being 

 inflected. The labellum thus acts like one of those conical traps 

 with the edges turned inwards, which are sold to catch beetles 

 and cockroaches in London kitchens. It could not creep out 

 through the slit between the folded edges of the basal part of the 

 labellum, as the elongated, triangular, rudimentary stamen here 

 closes the passage. Ultimately it forced its way out through one of 

 the small orifices close to one of the anthers, and was found when 

 caught to be smeared with the glutinous pollen. I then put the same 

 bee into another labellum ; and again it crawled out through one 

 of the small orifices, always covered with pollen. I repeated the 

 operation five times, always with the same result. I afterwards 

 cut away the labellum, so as to examine the stigma, and found its 

 whole surface covered with pollen. It should be noticed that an 

 insect in making its escape, must first brush past the stigma and 

 afterwards one of the anthers, so that it cannot leave pollen on 

 the stigma, until being already smeared with pollen from one 

 flower it enters another ; and thus there will be a good chance of 

 cross-fertilization between two distinct plants. . . . Thus the 

 use of all parts of the flower, namely, the inflected edges, or the 

 polished inner sides of the labellum ; the two orifices and their 

 position close to the anthers and stigma, the large size of the 

 medial rudimentary stamen, are rendered intelligible. An insect 

 which enters the labellum is thus compelled to crawl out by one 

 of the two narrow passages, on the sides of which the pollen- 

 masses and stigma are placed." 



These common orchids, which are not at all difficult to 

 naturalize in a well-drained, shady spot in the garden, should be 

 lifted with a good ball of earth and plenty of leaf-mould imme- 

 diately after flowering. Here we can note little American An- 

 drena bees unwittingly becoming the flower's slaves. Several 

 species of exotic cypripediums are so common in the city florist's 

 shops every one has an opportunity to study their marvellous 

 structure. 



The similar Small, Yellow Lady's Slipper (C. paroiflprutri) t a 

 delicately fragrant orchid about half the size of its big sister, has 

 a brighter yellow pouch, and occasionally its sepals and petals are 

 purplish. As they usually grow in the same localities, ana have the 

 same blooming season, opportunities for comparison are not lack- 

 ing. This fairer, sweeter, little orchid roams westward as far as 

 the State of Washington. 



286 



