THE ORCHID GENERA 47 



neath it. Each of these two species of Euglossa which 

 visited the flowers adopted a different course in entering 

 the cavity of the lip in their search for nectar. The 

 smaller species alighted invariably on the column, 

 walked down its face into the lip and took up the 

 nectar, retreating, when finished, by walking backward 

 on the face of the column again. While inside the 

 flower, however, it kept on without cessation, brushing 

 by contraction the top of the column with the end of its 

 body. By this process, if a male flower were approached 

 and treated in the same way that these female flowers 

 were treated, the pollina would be detached and would 

 adhere to the bee's body, and when the female flower in 

 turn was visited it would be fertilised by the stigma, 

 which is near the end of the column, being brushed by the 

 column, through the contractions of body I have described. 

 The larger species, however, invariably adopted a diffe- 

 rent course. It alighted on the summit of the lip and 

 walked in, as a house fly walks on a ceiling, and in doing 

 so its back invariably touched the top of the column. In 

 this way the pollina would be liberated by the pressure, 

 and would stick to the back of the insect, and when a 

 female flower was entered it would rub against the 

 stigmatic surface, thus effecting fertilisation of the 

 flower. The sportive character of Catasetums is now 

 well known among Orchidists. All the species appear 

 to have the same wonderful power of ejecting their 

 pollen masses, as, on touching the extremity of the 

 column, wherein lie hidden the column horns, with a 

 pencil, the anther case flies off with an elastic force, and 

 takes along with it the pollen mass, the gland at the 

 base of which is covered with a glutinous substance, by 

 which it adheres to anything with which it comes in 

 contact. I may here remark that these singular flowers 

 are not irritable when they first open, it being nearly 

 always several days before they will answer to the touch 



