183 



may remove. The thin edges of the clinandrum do not border the an- 

 ther-lid equally on every side, for if it were so the raising of the lid 

 would brush the prominent pollen-masses against the front edge, caus- 

 ing the pollen to fall useless into the bottom of the pit, and thus ren- 

 der the plant self-destructive ; to obviate this, the edge of the clinan- 

 drum in front is hollowed and thrust forward slightly, leaving sufficient 

 room for the passage of the pollen-masses at the raising of the lid ; 

 the resulting space is not, however, left completely open, but, as if to 

 prevent the accidental removal of the pollen-masses, the lower front 

 edge of the anther-lid is furnished with a row or fringe of elongated 

 papillae, quite effectually closing the opening. So by this means, al- 

 though the masses of pollen and the stigmatic surface are in close con- 

 tiguity, they are entirely prevented by the exact structure and 

 sculpture of the parts of the flower from ever coming in contact with 

 one another except through foreign aid ; for the pollen-masses are 

 seen to be completely packed away in a deep pit, pressed down by a 

 ponderous lid, whose elastic hinge will not allow its elevation without 

 considerable force : and should by any possibility a portion of the 

 pollen escape through the opening in front, really effectually closed 

 by the fringe, it would drop, not upon the stigmatic surface, but upon 

 the labellum, opposite to it. 



By what means does an insect effect the fertilization of this plant ? 

 Its probable action may be readily and successfully imitated. Flying 

 to the flower intent upon its sweets, it would alight upon the label- 

 lum, and, creeping in, would strike its head and back first against the 

 protruding anther-lid, only pressing it down more tightly, effect- 

 ing nothing, and then against the stigmatic surface. The passage 

 into the flower is narrow, allowing no room for anything but a very 

 small insect to turn round in, so that no sooner does the insect with- 

 draw itself backward, than the top of the back and of the head strik- 

 ing, as it almost infallibly must, against the front of the anther-lid 

 (which at its upper portion projects forward somewhat, in order the 

 more readily to catch the passing head), raises it more and more with 

 its continued withdrawal, rolling the outer and under surface of the 

 lid against the upper and front portion of the head of the insect, till 

 it has passed, when the lid snaps back to its original position, leaving 

 the pollen-masses adhering to the upper portion of the front of the 

 insect's head ; — or if only a portion of the pollen be removed, the 

 lid, being closed again, is ready for the services of the next visitor. 

 The insect flies to another flower, and, striking with the top of the head 

 plump against the viscid stigmatic surface, leaves the pollen glued to 

 it, and thus fertilization is ensured. 



There are several minor points of structure in the plant, all seem- 

 ing to aid in this special mode of fertilization through the agency of 



