Page:Darwin - The various contrivances by which orchids are fertilized by insects (1877).djvu/195

. VI. This spout is closely over-arched by the end of the column, which bears the stigma and pollen-masses in such a position, that an insect forcing its way out of the bucket through this passage would first brush with its back against the stigma and afterwards against the viscid discs of the pollinia, and thus remove them. We are now prepared to hear what Dr. Crüger says about the fertilisation of an allied species, the C. macrantha, the labellum of which is provided with crests. I may premise that he sent me specimens of the bees which he saw gnawing these crests, and they belong, as I am informed by Mr. F. Smith, to the genus Euglossa. Dr. Crüger states that these bees may be "seen in great numbers disputing with each other for a place on the edge of the hypochil (i. e. the basal part of the labellum). Partly by this contest, partly perhaps intoxicated by the matter they are indulging in, they tumble down into the 'bucket,' half-full of a fluid secreted by organs situated at the base of the column. They then crawl along in the water towards the anterior side of the bucket, where there is a passage for them between the opening of this and the column. If one is early on the look-out, as these Hymenopteræ are early risers, one can see in every flower how fecundation is performed. The humble-bee, in forcing its way out of its involuntary bath, has to exert itself considerably, as the mouth of the epichil (i. e. the distal part of the labellum) and the face of the column fit together exactly, and are very stiff and elastic. The first bee, then, which is immersed will have the gland