Page:Darwin - The various contrivances by which orchids are fertilized by insects (1877).djvu/200

180 other hand, the pedicels are fastened down in a curved position; and when freed by the rupture of the attached edges of the disc, they straighten themselves with such force, that not only do they drag the balls of pollen together with the anther-cells from their places of attachment, but the whole pollinium is jerked forward, over and beyond the tips of the so-called antennæ, to the distance sometimes of two or three feet. Thus, as throughout nature, pre-existing structures and capacities are utilised for new purposes.

Catasetum saccatum. —I will first describe the male forms, belonging to five species, which are included under the generic name of Catasetum. The general appearance of the present species is represented in the following woodcut, fig. 28. A side view of the flower, with all the petals and sepals excepting the labellum cut off, is shown by B; and A gives a front view of the column. The upper sepal and two upper petals surround and protect the column; the two lower sepals project out at right angles. The flower stands more or less inclined to either side, but with the labellum downwards, as represented in the drawing. The dull coppery and orange-spotted tints,—the yawning cavity in the great fringed labellum,—the one antenna projecting with the other hanging down—give to these flowers a strange, lurid, and almost reptilian appearance.

In front of the column, in the middle, the deep stigmatic chamber (fig. 28, A, s), may be seen; but this is best shown in the section (fig. 29, C, s), in which all